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For flyback-type converter

Subclass of:

363 - Electric power conversion systems

363013000 - CURRENT CONVERSION

363015000 - Including D.C.-A.C.-D.C. converter

363016000 - Having transistorized inverter

363020000 - Single-ended, separately-driven type

363210010 - With automatic control of the magnitude of output voltage or current

Patent class list (only not empty are listed)

Deeper subclasses:

Class / Patent application numberDescriptionNumber of patent applications / Date published
363210170 Having output current feedback 75
363210150 Having feedback isolation (e.g., optoisolator, transformer coupled, etc.) 47
363210180 Utilizing pulse-width modulation 44
363210130 Having digital logic 40
363210160 Having feedback winding inductively coupled to inverter inductive device (e.g., tertiary winding, etc.) 39
363210140 Having synchronous rectifier 28
Entries
DocumentTitleDate
20110182088QUASI-RESONANT POWER SUPPLY CONTROLLER AND METHOD THEREFOR - In one embodiment, a quasi-resonant power supply controller is configured to select particular valley values of a switch voltage to determine a time to enable a power switch. The valleys values are selected responsively to a range of values of a feedback signal.07-28-2011
20120170329METHOD AND APPARATUS FOR IMPLEMENTING AN UNREGULATED DORMANT MODE IN A POWER CONVERTER - A control circuit includes a drive signal generator controlling switching of a power switch to regulate a flow of energy to one or more loads coupled to a power converter output. A regulator circuit charges a capacitor to a first voltage and stops charging the capacitor if an energy requirement of the one or more loads falls below a threshold. The regulator again charges the capacitor after the capacitor is discharged from the first voltage to a second voltage. An unregulated dormant mode control circuit renders dormant the drive signal generator and the regulator circuit while the capacitor is discharged from the first voltage to the second voltage causing the regulation of the flow of energy to the power converter output to cease. The drive signal generator and the regulator circuit are powered up after the capacitor is discharged from the first voltage to the second voltage.07-05-2012
20080259653METHOD AND APPARATUS FOR CONDITIONAL RESPONSE TO A FAULT CONDITION IN A SWITCHING POWER SUPPLY - Techniques are disclosed to regulate an output of a power converter. One example power converter controller circuit includes a line sense input to be coupled to receive a signal representative of an input voltage of a power converter. A feedback input to be coupled to receive a feedback signal representative of an output of the power converter is also included. A drive signal generator is also included to generate a drive signal coupled to control switching of a switch to provide a regulated output parameter at the output of the power converter in response to the feedback signal. The drive signal generator is coupled to receive a plurality of inputs including the line sense input and the feedback input. The drive signal generator is coupled to latch the power converter into an off state in response to a detection of a fault condition in the power converter as detected by the plurality of inputs if the power converter input voltage is above a first threshold level. The drive signal generator to be unresponsive to the signal representative of the power converter input voltage while the controller is regulating the output parameter at the output of the power converter.10-23-2008
20080259652Compensating for base current in a primary side power converter that uses an NPN bipolar transistor - A comparing circuit and a control loop are used to maintain the peak level of current flowing through an inductor of a flyback converter. An inductor switch control signal controls a switch through which the inductor current flows. The inductor current increases at a ramp-up rate during a ramp time and stops increasing at the end of the ramp time. The comparing circuit generates a timing signal that indicates a target time at which the inductor current would reach a predetermined current limit if the inductor current continued to increase at the ramp-up rate. The control loop then receives the timing signal and compares the target time to the end of the ramp time. The pulse width of the inductor switch control signal is increased when the target time occurs after the end of the ramp time. Adjusting the frequency and pulse width controls the peak of the inductor current.10-23-2008
20080259651Constant current and voltage controller in a four-pin package with dual-use pin - A comparing circuit and a control loop are used to maintain the peak level of current flowing through an inductor of a flyback converter. An inductor switch control signal controls an inductor switch through which the inductor current flows. The inductor current increases at a ramp-up rate during a ramp time and stops increasing at the end of the ramp time. The comparing circuit generates a timing signal that indicates a target time at which the inductor current would reach a predetermined current limit if the inductor current continued to increase at the ramp-up rate. The control loop then receives the timing signal and compares the target time to the end of the ramp time. The pulse width of the inductor switch control signal is increased when the target time occurs after the end of the ramp time. Adjusting the pulse width controls the peak of the inductor current.10-23-2008
20080259650Changing switching frequency of a primary side power converter to compensate for inductance variation - A comparing circuit and a control loop are used to maintain the peak level of current flowing through an inductor of a flyback converter. An inductor switch control signal controls a switch through which the inductor current flows. The inductor current increases at a ramp-up rate during a ramp time and stops increasing at the end of the ramp time. The comparing circuit generates a timing signal that indicates a target time at which the inductor current would reach a predetermined current limit if the inductor current continued to increase at the ramp-up rate. The control loop then receives the timing signal and compares the target time to the end of the ramp time. The pulse width of the inductor switch control signal is increased when the target time occurs after the end of the ramp time. Adjusting the frequency and pulse width controls the peak of the inductor current.10-23-2008
20110194313ACTIVE SNUBBER CIRCUIT AND POWER SUPPLY CIRCUIT - An active snubber circuit for a switching power supply, in which a main switching element repeatedly operates an on-off operation so that current intermittently flows in a primary coil, has a capacitor for surge voltage absorption, a sub-switching element and a sub-control circuit controlling the sub-switching element. A circuit in which the capacitor for surge voltage absorption and the sub-switching element are connected in series is connected in parallel with the primary coil, and the sub-control circuit turns on the sub-switching element for a predetermined time period just after the main switching element is off.08-11-2011
20110194312METHOD AND APPARATUS FOR DETERMINING ZERO-CROSSING OF AN AC INPUT VOLTAGE TO A POWER SUPPLY - An example controller for a switched mode power supply includes a drive signal generator and a zero-crossing detector. The drive signal generator is to be coupled to control switching of a switch included in the power supply to regulate an output of the power supply. The zero-crossing detector is coupled to the drive signal generator and coupled to receive a current sense signal representative of a switch current flowing through the switch. The zero-crossing detector generates a zero-crossing signal in response to comparing the current sense signal with a reference signal representative of a zero-crossing current threshold. The zero-crossing signal indicates when a zero-crossing condition of an ac line input voltage of the power supply exists.08-11-2011
20110194311PHASE ANGLE MEASUREMENT OF A DIMMING CIRCUIT FOR A SWITCHING POWER SUPPLY - An example controller for a switched mode power supply includes a zero-crossing detector, a feedback reference circuit, and a drive signal generator. The zero-crossing detector is coupled to generate a zero-crossing signal representative of a length of time that a zero-crossing condition of an input voltage of the power supply exists. The feedback reference circuit is to be coupled to receive a feedback signal and a reference signal, where the feedback signal is representative of an output of the power supply and where the controller is adapted to adjust the reference signal in response to the length of time that the zero-crossing condition exists. The drive signal generator is to be coupled to control switching of a switch included in the power supply in response to an output of the feedback reference circuit to regulate an output of the power supply.08-11-2011
20120176820Switching Power Converter Having Optimal Dynamic Load Response with Ultra-Low No Load Power Consumption - A switch controller is disclosed that adaptively controls the operating frequency of a switching power converter in order to improve one-time load response and repetitive dynamic load responses. During a transition from a high load to low load condition, the switch controller clamps the operating frequency of the switching power converter at an intermediate frequency for a period of time before allowing the operating frequency to return to a frequency associated with the low load condition. The clamped frequency is higher than the frequency associated with the low load condition thereby allowing improved response to a subsequent load change to a high load condition. Thus, the system improves dynamic load response without compromising no-load power consumption.07-12-2012
20100046254ENERGY EFFECTIVE SWITCHING POWER SUPPLY APPARATUS AND AN ENERGY EFFECTIVE METHOD THEREOF - An energy effective switching power supply apparatus and an energy effective method thereof. The energy effective switching power supply apparatus includes a power transforming part having first and second coils to induce a voltage to the second coil using interactions between the first and the second coils with respect to the input voltage, a power outputting part to output a sensing signal when it is determined that a first DC voltage output by rectifying and smoothing the voltage induced to the second coil is greater than or equal to a reference voltage level, and a switching controlling part to adjust a switching frequency of a switching device to interrupt a current flowing in the first coil of the power transforming part when the sensing signal is received. Accordingly, a switching loss is controlled and an energy loss is reduced.02-25-2010
20100046253Control Circuit for a Switched-Mode Power Supply with Regulation Based on the Secondary-Side Current Flow Time Period - A control circuit for a primary controlled switched-mode power supply that has a primary-side switch and a transmitter. It also relates to an associated switched-mode power supply. The control circuit can be connected to a control input of the primary-side switch so that the primary-side switch is controlled based on a secondary-side current flow time period in which a current flows through the secondary-side winding of the transmitter in order to regulate the output voltage. The secondary-side current flow time period can be used as a control parameter instead of the actual output voltage in order to then control the primary-side switch. Because the secondary-side current flow time period can be determined indirectly on the primary side, no direct feedback is necessary between the output voltage on the secondary side and the control circuit on the primary side.02-25-2010
20100027297Step-Up Converter Systems and Methods - Methods and systems with a step-up converter are provided based on a boost converter. In one aspect, a step-up converter includes: a boost converter having a first inductor; a second inductor paired on a core with the first inductor; and a rectifier circuit coupled with the second inductor to generate a direct current output.02-04-2010
20120182769DC-DC CONVERTER, POWER SUPPLY UNIT AND AN INFORMATION PROCESSING APPARATUS - A DC-DC converter is disclosed that includes a first winding of a first transformer to which direct current power is supplied, a switching element configured to be connected in series with the first winding of the first transformer, a first winding of a second transformer and a capacitor configured to be connected in series with each other and in parallel with the switching element, a second winding of the first transformer configured to be coupled with the first winding of the first transformer, output terminals configured to be connected to the second winding of the first transformer and to output direct current power, and a pair of second windings of the second transformer configured to be coupled with the first winding of the second transformer, the second windings of the second transformer being connected in parallel with each other with reverse polarity between the output terminals.07-19-2012
20130070486CONTROL METHODS AND CONTROLLERS - Control methods and controller thereof for a power supply including a power switch and an inductor. The power switch is turned on to increase the inductor current through the inductor, which is sensed to generate a current-sense signal. The current-sense signal is added up with an adjusting signal to generate a summation signal. The power switch is turned off if the summation signal is higher than a peak limit. The turn-on time of the power switch is detected to update the adjusting signal.03-21-2013
20130088897CONTROL INTEGRATED CIRCUIT FOR A POWER TRANSISTOR OF A SWITCHING CURRENT REGULATOR - An integrated circuit controls a switch of a switching current regulator. The current regulator comprises primary and secondary windings where a first and a second current flow, respectively. The switch is adapted to initiate or interrupt the circulation of the first current in the primary winding. The control integrated circuit comprises a comparator configured to compare a first signal representative of said first current to a second signal and a divider circuit configured to generate said second signal as a ratio of a third signal, proportional to a voltage on the primary winding, with a voltage on a capacitor. The capacitor is charged by a further current controlled by the third signal when the second current is different from zero. The capacitor is discharged through a parallel-connected resistor when the value of said second current is substantially zero.04-11-2013
20090040793Start-up time reduction in switching regulators - A start-up time accelerator is described for a switch controller that controls turning on or off a switch in a switching regulator. The start-up time accelerator uses the switch as a current amplifier and provides the amplified current to a capacitor using a current amplification path. In one example, the capacitor provides the bias voltage to a switch controller for the switch. Providing an amplified current to the capacitor accelerates the rate at which the bias voltage increases and reduces the time until the bias voltage reaches the turn-on threshold voltage of the switch controller. After the turn-on threshold voltage of the switch controller is reached, a second path is enabled for current to and from the capacitor and the capacitor provides the bias voltage to the switch controller until a voltage from an output voltage terminal is sufficiently high to provide the bias voltage for the switch controller through an auxiliary winding of a transformer.02-12-2009
20090091952DC-DC CONVERTER - Disclosed is a DC-DC converter for suitably converting the voltage of a solar panel into a desired output voltage to be supplied to various observation equipment installed in an artificial satellite. The DC-DC converter 04-09-2009
20130058137SYSTEMS AND METHODS OF PRIMARY-SIDE SENSING AND REGULATION FOR FLYBACK POWER CONVERTER WITH HIGH STABILITY - System and method for regulating an output voltage of a power conversion system. The system includes an error amplifier coupled to a capacitor. The error amplifier is configured to receive a reference voltage, a first voltage, and an adjustment current and to generate a compensation voltage with the capacitor. The first voltage is associated with a feedback voltage. Additionally, the system includes a current generator configured to receive the compensation voltage and generate the adjustment current and a first current, and a signal generator configured to receive the first current and a second current. The signal generator is further configured to receive a sensing voltage and to generate a modulation signal. Moreover, the system includes the gate driver directly or indirectly coupled to the signal generator and configured to generate a drive signal based on at least information associated with the modulation signal.03-07-2013
20120224398Charge-transfer conditioning circuit - A conditioning circuit for the transfer of electric charge, which includes a converter module including an energy-storage element applied to which is an input voltage (Vi) and a respective field-effect-transistor switch controlled by a respective driving signal (Vpa, Vpb) for selectively enabling transfer of charge from the energy-storage element to an energy-storage circuit. The field-effect-transistor switch includes a corresponding field-effect transistor and a biasing circuit for biasing a substrate of the transistor, the biasing circuit being connected between the substrate and a reference node at a potential suitable for enabling operation of the transistor in the linear region or in the region of saturation, the biasing circuit being configured for providing a limiting resistance in regard to the current that flows from the reference node in the transistor when it operates in the inhibition region.09-06-2012
20120224397DEVICES AND METHODS OF CONSTANT OUTPUT CURRENT AND VOLTAGE CONTROL FOR POWER SUPPLIES - Power controllers, control methods and related integrated circuits for power supplies are disclosed. A power supply has a power switch and an inductive device. An exemplifying power controller comprises a first current source, a discharge time sensor, a representative current generator, and a pulse width modulator. The first current source generates a target current pouring to a compensation node. The discharge time sensor determines a discharge time of the inductive device. The representative current generator generates a representative current representing an inductor current of the inductive device. The pulse width modulator determines an output power of the power supply according to the compensation voltage at the compensation node. The representative current drains from the compensation node during the discharge time.09-06-2012
20090237960SWITCH MODE POWER SUPPLY CONTROLLERS - This invention relates to SMPS controllers employing primary side sensing. We describe a system for identifying a knee point in a sensing waveform, at which the output voltage of the SMPS may be sampled accurately on the primary side. The system identifies the knee point by fitting a tangent to a portion of a power transformer voltage waveform, and samples the voltage waveform at the knee point to determine the SMPS output voltage. In preferred embodiments this technique is implemented using a decaying peak detector, providing a timing signal indicating detection of the knee point. Sample/hold and error amplifier circuits may be employed to achieve output voltage regulation.09-24-2009
20090231888METHOD AND APPARATUS FOR FAULT DETECTION IN A SWITCHING POWER SUPPLY - Techniques are disclosed to detect a fault in the feedback circuit of a switching power supply while the power supply operates in a mode where the output is below its regulated value. The power supply delivers maximum power at a given switching frequency without a feedback signal while the output is below its regulated value. A fault protection circuit substantially reduces the average output power if there is no feedback signal for the duration of a fault time. When there is no feedback signal, the power supply increases the maximum output power by increasing the switching frequency before the end of the fault time to increase the output to a regulated value. The presence of a feedback signal when the output reaches a regulated value restores the original switching frequency and returns the output to its unregulated value. The absence of a feedback signal at the end of the fault time engages the fault protection circuit to substantially reduce the output power.09-17-2009
20090067201Isolated Switched-mode Power Supply With Output Regulation From Primary Side - Embodiments disclosed herein describe an isolated switched-mode power supply with its output regulated from the primary side, by generating a sensing current using a sensing element coupled to the output of the power supply, and measuring a scaled version of the sensing current which depends on the output voltage, and calculating an estimate voltage representing the output voltage, and regulating the output of the isolated switched-mode power supply based on the estimate voltage.03-12-2009
20120113688Interleaved flyback converter device with leakage energy recycling - An interleaved flyback converter device with leakage energy recycling includes: two flyback converters and an input power. Each flyback converter includes a capacitor, a switch, two diodes, and a transformer. The input power is connected to the capacitors of the two flyback converters respectively. By using the capacitors as input voltage, the two flyback converters are provided with lower voltage rating. The diodes are used to recycle leakage energy directly, and to clamp voltage on power components. Therefore, in addition to enhancing efficiency via recycling leakage energy, the two flyback converters have lower switching losses due to lower switching voltage.05-10-2012
20130163291SWITCH CIRCUIT, POWER SUPPLY DEVICE INCLUDING THE SAME, AND DRIVING METHOD THEREOF - The present invention relates to a switch circuit, a power supply including the same, and a method for driving the power supply. When a load of the power supply represents an overload state, a sense resistor for controlling a drain current flowing through a power switch is controlled. In this instance, the sense resistor is controlled according to an on-time of the power switch.06-27-2013
20120268970ELECTRIC GENERATING SYSTEM USING SOLAR CELL - An electric generating system using a solar cell improves the quality of output power by including a converter for converting an output voltage generated from the solar cell into a DC voltage in a pulse shape. An inverter converts the DC voltage in the pulse shape into an AC voltage and applies the AC voltage to a power system and a control device for determining whether an erroneous operation of the electric generating system using the solar cell is generated or not based on an output voltage of the solar cell, an output current of the solar cell and a voltage of the power system. At least one inverter switching device among a plurality of inverter switching devices performs a switching at a frequency higher than a frequency during a normal operation at an interval where the erroneous operation is generated.10-25-2012
20110013425High step-up ratio soft-switched flyback converter - A converter circuit includes a transformer having a first side and a second side. The converter circuit also includes a switch coupled to the first side of the transformer. The converter circuit further includes a rectifying diode coupled to the second side of the transformer and to a first output terminal of the converter circuit. In addition, the converter circuit includes a clamping diode coupled to the second side of the transformer, to the rectifying diode, and to a second output terminal of the converter circuit. The converter circuit may include a boost section and a flyback section. The converter circuit may also include an active clamp and an isolated flyback section.01-20-2011
20100067263DUAL INTERLEAVED FLYBACK CONVERTER FOR HIGH INPUT VOLTAGE - An integrated magnetic flyback converter includes interleaved phases that can be connected in series for an input stage and in parallel for an output stage. An integrated magnetic core has legs with gaps that may weaken a coupling between a primary and secondary of the associated transformer. The primary and secondary of the transformer may be inversely coupled for each phase. The transformer leg gaps permit each phase to be operated with a duty cycle ratio greater than 50%. The interleaved converter has reduced output current ripple, reduced input component voltage stress, reduced magnetizing inductance, reduced magnetic component physical size and reduced common integrated magnetic core current spikes.03-18-2010
20100165671Switched-mode Power Supplies - This disclosure relates to switched-mode power supplies, to transformers for such power supplies, and to methods of operating switched-mode power supplies. A switch mode power supply (SMPS), the switched-mode power supply having a power input, a switch, a transformer, and a power output; said transformer having a primary winding on a primary side of said power supply coupled to said power input via said switch, and a secondary winding on a secondary side of said switched-mode power supply coupled to said power output; wherein said transformer further includes first and second auxiliary windings, wherein said first auxiliary winding is more closely coupled to said primary winding than to said secondary winding and wherein said second auxiliary winding is more closely coupled to said secondary winding than to said primary winding.07-01-2010
20090207636Constant current and voltage controller in a small package with dual-use pin - A comparing circuit and a control loop are used to maintain the peak level of current flowing through an inductor of a flyback converter. An inductor switch control signal controls an inductor switch through which the inductor current flows. The inductor current increases at a ramp-up rate during a ramp time and stops increasing at the end of the ramp time. The comparing circuit generates a timing signal that indicates a target time at which the inductor current would reach a predetermined current limit if the inductor current continued to increase at the ramp-up rate. The control loop then receives the timing signal and compares the target time to the end of the ramp time. The pulse width of the inductor switch control signal is increased when the target time occurs after the end of the ramp time. Adjusting the pulse width controls the peak of the inductor current.08-20-2009
20110286247SENSING ARRANGEMENTS - A sensing arrangement and method a sense winding is used to provide a voltage which represents the voltage appearing across an in-circuit magnetic component. In a flyback phase, when the component is supplying the output, that voltage represents an output voltage and in a supply phase, the supply voltage. This arrangement provides a solution to the problem of the disparity in magnitude of sense winding output during the two phases by proving a pull-up resistor arranged to apply bias to the voltage measured, the pull-up being to a first level during the supply period and to a second value during the flyback period, the first and second levels being selected such that the voltage across the sense winding is scaled differently during the supply period and the flyback period. The invention is suitable for use in a transformer based flyback power converter in which the magnitude disparity problem may be exacerbated by a turns ratio.11-24-2011
20080304292ISOLATED HIGH POWER BI-DIRECTIONAL DC-DC CONVERTER - A bi-directional dc-dc converter is provided that may provide voltage conversion for two separate electrical power systems. The two electrical power systems may have different functions, electrical requirements and power transfer directions. The bi-directional dc-dc converter may include back-to-back bi-directional dc-dc converter circuits isolated from each other by a transformer. Multiple such dc-dc converters may be connected in parallel to increase power capability. Phase shift pulse width modulation (PWM) may be used to switch the parallel dc-dc converters so as to decrease both voltage ripple and current ripple. The number of dc-dc converters may be modified to meet the different needs of various electric power systems. A single bi-directional dc-dc converter of the invention may be employed to provide electric power conversion for multiple electric power systems, even where those systems have different power requirements and different power transfer directions.12-11-2008
20110292691ISOLATED SWITCHING POWER SUPPLY APPARATUS - In an ON/OFF type isolated DC-DC converter that stores electromagnetic energy in a main transformer during an ON period of a power switch and releases the electromagnetic energy to an output during an OFF period of the power switch, high-speed, highly stable output voltage control without the need for a photocoupler, for which the allowable temperature range is relatively narrow and the current transfer ratio changes over time, is performed. An integrating circuit including a resistor and a capacitor generates a ramp wave, and the ramp wave is superposed on a reference voltage of a reference voltage source Vref through a capacitor. A comparator compares a voltage Vo that is proportional to an output voltage of a converter with the reference voltage on which the ramp wave has been superposed, and transmits an inversion timing signal through a pulse transformer. During an ON period of a power switch, when the voltage Vo that is proportional to the output voltage exceeds the reference voltage on which the ramp wave has been superposed, the comparator is inverted and the power switch is turned OFF.12-01-2011
20110292690Multi-winding high step-up DC-DC converter - A multi-winding high step-up DC-DC converter includes a three-winding transformer to transform a low DC voltage to a high DC voltage; a power switch to control the energy flux of the primary winding of the three-winding transformer based on turning on/off the power switch; a first diode to control the current of the first secondary winding of the three-winding transformer; a second diode to control the current of the second secondary winding of the three-winding transformer; and a third diode to control the current of the primary winding. When the DC-DC converter is in the first operation state, the switch and the second diode are in on state, and the first and the third diodes are in off state. When the DC-DC converter is in the second operation state, the switch and the second diode are in off state, and the first and the third diodes are in on state.12-01-2011
20110267848POWER CONVERTER - Reduction of power loss and operation in a two-phase mode are made possible.11-03-2011
20100165670MULTI-OUTPUT SYNCHRONOUS FLYBACK CONVERTER - The present application concerns a multi-output synchronous Flyback converter. The Flyback converter comprises a primary controlled switch (07-01-2010
20110261595METHOD AND SYSTEM FOR DELIVERING A CONTROLLED VOLTAGE - In general, in one aspect, the invention relates to a method for delivering a controlled voltage. The method involves, during a first electric pulse delivered to a primary transformer, holding a first switching section open to isolate the controlled voltage, where the first electric pulse creates a first magnetic flux in a core of the primary transformer, and where the first magnetic flux generates a direct current (DC) magnetizing current. The method further involves receiving the controlled voltage from a voltage source using the DC magnetizing current at a first switching section, and upon termination of the first electric pulse, closing the first switching section to deliver the controlled voltage to the primary transformer.10-27-2011
20100124080CURRENT CONTROL METHOD AND APPARATUS - Current control method and apparatus are disclosed. A current limiter is coupled to a switch connected in series with an energy transfer element of a power supply. The current limiter detects a current flowing through the switch and, when the current exceeds a current limit signal, turns off the switch. A limit signal generator provides the current limit signal, detects the maximum current value of the current, and updates the current limit signal according to the maximum current value and an ideal current limit value.05-20-2010
20120140531FLYBACK PRIMARY SIDE OUTPUT VOLTAGE SENSING SYSTEM AND METHOD - A method and apparatus of primary side output voltage sensing for a flyback power converter preserves secondary-side tranformer isolation without the use of opto-isolators and does not require multiple high-speed sample and hold circuits. A timing circuit measures the duration of the diode conduction interval during a first PWM control cycle and applies this measurement to set the voltage sampling time of the feedback loop during the next PWM cycle. The voltage sampling time for the next PWM cycle is configurable and may be set to occur near the middle of the diode conduction interval or near the end of the diode conduction interval. The cycle-to-cycle PWM duty cycle adjustment step size may be limited to ensure that the diode conduction interval does not vary substantially from cycle to cycle.06-07-2012
20120188800ASYMMETRIC SWITCH FORWARD CONVERTER - A switching circuit for use in a power supply includes a first active switch coupled to a first terminal of a primary winding of a transformer. A second active switch is coupled to a second terminal of the primary winding of the transformer. An output capacitance of the first active switch is greater than an output capacitance of the second active switch. A first passive switch is coupled to the second active switch and to the second terminal of the primary winding. A second passive switch is coupled to the first active switch and to the first terminal of the primary winding. A reverse recovery time of the first passive switch is greater than a reverse recovery time of the second passive switch. A recovery circuit is coupled to receive a current from the first passive switch.07-26-2012
20100085779SWITCHING POWER SOURCE APPARATUS - In a switching power source of a flyback converter system according to the present invention, large electric power can be applied, by reducing loss of a switching element, a coil, and an output smoothing circuit, input voltage is applied to a primary coil of a transformer, and switching drive of the input voltage is carried out by a switching element, so that direct-current electric power is outputted from a secondary coil of the transformer through a rectifier circuit. The power source apparatus includes a trigger-control circuit which detects direct-current output voltage to control an “on” period, detects that current of the secondary coil becomes zero based on a voltage signal from a control coil, and turns on the switching element, and a timer circuit which is operated according to the voltage signal of the control coil, and gives an ON signal to the trigger-control circuit according to a timing signal.04-08-2010
20110170319METHOD FOR CONTROLLING A SWITCHING REGULATOR AND RELATED SWITCHING REGULATOR - An embodiment of a power-supply controller comprises a switching-control circuit, an error amplifier, and a signal generator. The switching-control circuit is operable to control a switch coupled to a primary winding of a transformer, and the error amplifier has a first input node operable to receive a feedback signal, a second input node operable to receive a comparison signal, and an output node operable to provide a control signal to the switching-control circuit. The signal generator is operable to generate either the feedback signal or the comparison signal in response to a compensation signal that is isolated from a secondary winding of the transformer and that is proportional to a load current through a conductor disposed between the secondary winding and a load.07-14-2011
20090262561METHOD AND APPARATUS TO IMPROVE REGULATION OF A POWER SUPPLY - Techniques are disclosed to regulate a power supply with a compensation signal generation circuit. One example regulated power supply includes a sense circuit coupled to sense an output voltage of the regulated power supply. The regulated power supply also includes a switching power converter circuit, which includes a switch coupled to be switched in response to a control signal received from the sense circuit to regulate the output voltage of the regulated power supply. The regulated power supply also includes a compensation signal generation circuit coupled to receive a switching signal representative of a switching of the switch in the switching power converter circuit. The compensation signal generation circuit is to generate a compensation signal responsive to the switching signal. The compensation signal is to be received by the sense circuit to modify the control signal.10-22-2009
20090296427METHOD AND APPARATUS TO LIMIT MAXIMUM SWITCH CURRENT IN A SWITCHING POWER SUPPLY - Techniques are disclosed to limit the current in a switch of a switching power supply. An example switching regulator circuit includes a power switch to be coupled to an energy transfer element of a power supply. A controller to generate a drive signal is coupled to be received by the power switch to control the switching of the power switch. A short on time detector is included in the controller. The short on time detector is to detect an occurrence of a threshold number of one or more consecutive short on times of the switch. A frequency adjuster is also included in the controller and coupled to the short on time detector. The frequency adjuster is to adjust an oscillating frequency of an oscillator included in the controller in response to the short on time detector.12-03-2009
20100220503METHOD AND APPARATUS FOR CONTROLLING THE MAXIMUM OUTPUT POWER OF A POWER CONVERTER - A controller for a power converter is disclosed. An example circuit controller according to aspects of the present invention includes an input voltage sensor to be coupled to receive an input signal representative of an input voltage of the power converter. A current sensor is also included and is to be coupled to sense a current flowing in a power switch. A drive signal generator is to be coupled to drive the power switch into an on state for an on time period and an off state for an off time period. The controller is coupled to adjust a duty cycle of the power switch in response to a difference between a time it takes the current flowing in the power switch to change between two current values when the power switch is in the on state and a control time period.09-02-2010
20090296426SWITCH MODE POWER SUPPLY - A low voltage power supply is disclosed. The power supply comprises a transformer having a primary winding, secondary and auxiliary windings wherein an interrupted current in said primary winding induces a voltage in each of the secondary and auxiliary windings, a first driver circuit and a second driver circuit connected in parallel to said primary winding, a first controller receiving said voltage from said auxiliary winding and connected to said first driver circuit and a second controller connected to said second driver circuit, providing a control signal to said second driver circuit when said auxiliary is below a predetermined value.12-03-2009
20120195076SYSTEMS AND METHODS FOR DYNAMIC THRESHOLD ADJUSTMENT WITH PRIMARY-SIDE SENSING AND REGULATION FOR FLYBACK POWER CONVERTERS - System and method for adjusting a threshold of a power conversion system. The system includes a threshold generator configured to receive a first signal and generate a threshold signal based on at least information associated with the first signal, a comparator configured to receive the threshold signal and a second signal and generate a comparison signal, and a gate driver configured to generate a drive signal based on at least information associated with the comparison signal. The gate driver is coupled to at least a switch configured to receive the drive signal and affect a current flowing through a primary winding coupled to a secondary winding. If the second signal is larger than the threshold signal in magnitude, the drive signal causes the switch to open. The drive signal is associated with a switching frequency.08-02-2012
20100061125Flyback boost circuit and strobe device using the same - A flyback boost circuit includes an output voltage detection terminal provided to a secondary winding of a transformer of the flyback boost circuit, and configured to detect an output voltage. Prior to the start of a boost operation, current is supplied to a secondary side of the transformer via the output voltage detection terminal to detect a voltage generated at the output voltage detection terminal, to thereby detect an unwired state by determining whether or not there is floating of the output voltage detection terminal or a grounding terminal of the secondary winding of the transformer.03-11-2010
20100142230SIMPLIFIED PRIMARY TRIGGERING CIRCUIT FOR THE SWITCH IN A SWITCHED-MODE POWER SUPPLY - The present invention relates to a trigger circuit for a switch in a switching power supply, especially in a primary-side, triggered switching power supply. The trigger circuit here comprises a feedback signal terminal for detecting an auxiliary voltage induced on a primary-side auxiliary winding of a transformer of the switching power supply, a supply voltage terminal for supplying the trigger circuit with a supply voltage, and a ground terminal for connecting the trigger circuit to a ground potential, wherein the feedback signal terminal is formed by the supply voltage terminal and the auxiliary voltage is superimposed on the supply voltage. Alternatively, the voltage of the auxiliary winding could be superimposed on the voltage on an additional pin that is used for detecting the primary peak current.06-10-2010
20090303756Maximum output power control of a flyback converter - A method and apparatus for a flyback converter estimate the next value of the current limit for the flyback converter according to a present current limit value to achieve the maximum output power control of the flyback converter. An arithmetic circuit is used to calculate the next current limit value according three parameters, the present current limit value, the value of the current sense signal taken after a first time period counting from the instant when the present duty is triggered, and the variation of the current sense signal during a second time period, thereby narrowing the tolerance of the output power from the flyback converter.12-10-2009
20110267847APPARATUS AND METHOD FOR DETECTING A CHANGE IN OUTPUT VOLTAGE OF AN ISOLATED POWER CONVERTER - A controller for use in a power converter to detect changes in output voltage. An example controller includes a drive circuit to generate a switching signal. The switching signal is coupled to be received by a power switch to be coupled to an energy transfer element and an input of the power converter to control a transfer of energy from the input of the power converter to an output of the power converter. An output voltage sensor is coupled to the drive circuit and coupled to receive a feedback signal representative of the output of the power converter. The output voltage sensor includes first and second pulse sampler circuits. The first pulse sampler circuit is coupled to capture a first peak voltage representative of a second peak of a ringing voltage of the feedback signal at a first time in the feedback signal. The second pulse sampler circuit is coupled to capture a second peak voltage representative of the second peak of the ringing voltage of the feedback signal at a second time in the feedback signal. The output voltage sensor is coupled to output a change signal to the drive circuit in response to the first and second peak voltages.11-03-2011
20120140530SWITCHING POWER SUPPLY APPARATUS AND IMAGE FORMING APPARATUS - A switching power supply apparatus includes a voltage holding unit which holds voltage generated in an auxiliary winding of a transformer, and a voltage detecting unit which detects voltage applied to the first switching unit. When the first switching unit operates such that voltage generated in a secondary winding of the transformer may be low, voltage is supplied from the voltage holding unit to the first switching unit in accordance with the voltage detected by the voltage detecting unit to thus turn on the first switching unit.06-07-2012
20120069609METHOD FOR LOWERING POWER LOSS AND CIRCUIT - A method and circuit for suppressing a bias current and decreasing power consumption. A current suppression circuit is coupled to a circuit element, which is capable of conducting the bias current. Coupling the current suppression circuit to the circuit element forms a node. In one operating mode, the current suppression circuit applies a voltage to the node in response to a heavy load. In another operating mode, the current suppression circuit lowers the voltage at the node in response to a light load or no load. Lowering the voltage at the node decreases the flow of bias current through the circuit element thereby lowering power loss.03-22-2012
20120069608CONTROL CIRCUIT WITH BURST MODE AND EXTENDED VALLEY SWITCHING FOR QUASI-RESONANT POWER CONVERTER - A control circuit for power converter according to the present invention comprises a PWM circuit generating a switching signal coupled to switch a transformer of the power converter. A feedback input circuit is coupled to an output of the power converter for generating a feedback signal. The feedback signal is coupled to turn off the switching signal. A detection circuit is coupled to the transformer for generating a valley signal in response to a waveform of the transformer. A frequency-variation circuit is coupled to receive the feedback signal and the valley signal for generating a frequency-variation signal. The frequency-variation signal is coupled to turn on the switching signal. A burst circuit is coupled to receive the feedback signal for generating a burst signal to disable the switching signal.03-22-2012
20110228568OFF-LINE CONVERTER WITH DIGITAL CONTROL - A circuit for regulating the level at a power converter output is disclosed. An example circuit includes an input for receiving a feedback signal. The feedback signal has a first feedback state that represents a level that is above a threshold level and a second feedback state that represents a level that is below the threshold level. An oscillator is included that provides an oscillation signal that cycles between two states. A switch having a first terminal, a second terminal and a control terminal are also included. The switch is operable to couple or decouple the first terminal and the second terminal in response to a control signal received at the control terminal. The control signal is responsive to the oscillation signal and to the first and second feedback states.09-22-2011
20090086513Control method and device for switching power supplies - A control device for controlling a switching power supply adapted to convert an input voltage into an output voltage according to a switching rate of a switching element. The control device includes first control means for switching the switching element in a first working mode at a constant frequency and second control means for switching the switching element in a second working mode at a variable frequency, under a maximum frequency, in response to the detection of a predefined operative condition of the switching power supply. The control device further includes means for selecting the first working mode or the second working mode.04-02-2009
20110228569Switching Power Converter for Reducing EMI from Ring Oscillation and Its Control Method - A switching power converter (09-22-2011
20090251931METHOD AND APPARATUS FOR CONDITIONAL RESPONSE TO A FAULT CONDITION IN A SWITCHING POWER SUPPLY - Techniques are disclosed to regulate an output of a power converter. One example power converter controller circuit includes a line sense input to be coupled to receive a signal representative of an input voltage of a power converter. A feedback input to be coupled to receive a feedback signal representative of an output of the power converter is also included. A drive signal generator is also included to generate a drive signal coupled to control switching of a switch to provide a regulated output parameter at the output of the power converter in response to the feedback signal. The drive signal generator is coupled to receive a plurality of inputs including the line sense input and the feedback input. The drive signal generator is coupled to latch the power converter into an off state in response to a detection of a fault condition in the power converter as detected by the plurality of inputs if the power converter input voltage is above a first threshold level. The drive signal generator to be unresponsive to the signal representative of the power converter input voltage while the controller is regulating the output parameter at the output of the power converter.10-08-2009
20100265741POWER FACTOR CORRECTING CONVERTER - A power factor correcting converter includes a DC-DC converter to convert a DC voltage, which is formed by rectifying an AC voltage of an AC power source through a rectifier, into a DC voltage of the DC-DC converter and a step-up converter to step up the DC voltage of the DC-DC converter. Secondary windings of a transformer Ta in the DC-DC converter are directly connected to the step-up converter.10-21-2010
20090316444SWITCHING POWER SUPPLY DEVICE - In a switching power supply device, a first switch element, which defines a main switch element of a DC-DC converter, and a third switch element, which defines a switch element of a power-factor correcting circuit, are controlled such that turn-on timings are synchronized while on-period control is independently performed to thereby prevent an increase in switching frequency and prevent noise by eliminating intermittent oscillation. Thus, it is possible to prevent intermittent oscillation control due to an increase in switching frequency of the first switch element under a light load state or a no load state. This eliminates problems of the frequency of intermittent oscillation that falls within an audible frequency range causing noise and increasing ripple voltage.12-24-2009
20100296319POWER SOURCE MODULE WITH BROAD INPUT VOLTAGE RANGE - The present invention discloses a power source module with a broad input voltage range, which includes a first and a second power source input terminals, a rectification filter circuit, and a conversion circuit connected between the first and the second power source input terminals and the rectification filter circuit, and the conversion circuit is connected with the first and the second power source input terminals through a rectification circuit and includes a first converter and a second converter, both of which are connected in parallel for output in a low voltage operation mode and in series for output in a high voltage operation mode. The power source module with a broad input voltage range according to the invention can be implemented so that an input voltage to a single converter can be half of a high input voltage, thereby addressing the problem of a limitation upon the voltage of the power device. The connection in parallel at a low voltage can facilitate choosing an alternative transistor with relatively small current. The loss of power devices can be dispersed to facilitate a thermal design. The utilization ratio of an input direct current filter capacitor can be improved greatly in the broad voltage range. The voltage range can be altered with merely simple pre-use configuration.11-25-2010
20100226151POWER CONVERSION CIRCUIT AND PORTABLE POWER SUPPLY HAVING SUCH POWER CONVERSION CIRCUIT - A power conversion circuit includes a flyback DC-to-DC converter, a capacitor and a DC-to-AC converter. The flyback DC-to-DC converter is used for receiving an input DC voltage and converting the input DC voltage into a constant high DC voltage. The capacitor is connected to the flyback DC-to-DC converter for filtering the high DC voltage. The DC-to-AC converter is connected to the capacitor for converting the filtered high DC voltage into an output AC voltage.09-09-2010
20100208500Detecting Light Load Conditions and Improving Light Load Efficiency in a Switching Power Converter - A switching power converter detects low load conditions based on the ratio of a first peak current value for peak current switching in constant voltage regulation mode to a second peak current value for peak current switching in constant current regulation mode. The power supply load is considered to have a low load if the ratio is lower than a predetermined threshold. Once a low load condition is detected, the switching frequency of the switching power converter is reduced to a level that minimizes switching loss in the power converter. In addition, the switching power converter also adjusts the switching frequency according to the sensed input line voltage. An offset is added to the switching period to reduce the switching frequency of the switching power converter, as the input line voltage is increased.08-19-2010
20110032731MULTIPLE INDEPENDENTLY REGULATED PARAMETERS USING A SINGLE MAGNETIC CIRCUIT ELEMENT - Methods, systems, and devices are described for using isolated and non-isolated circuit structures and control methods for achieving multiple independently regulated input and output parameters using a single, simple, primary magnetic circuit element. For example, structures and methods are revealed for achieving single-stage power factor correction with high power factor and multiple independently regulated outputs using a single, simple, primary magnetic circuit element. Other structures and methods are revealed for achieving multiple independently regulated outputs without power factor correction using a single primary magnetic circuit element for both isolated and non-isolated power conversion applications.02-10-2011
20100321962Frequency Modulation Controller, Switch Mode Power Supply Including The Same, And Switching Operation Frequency Modulation Method - The present invention relates to switching operation frequency modulation for reducing an output voltage ripple.12-23-2010
20100321961INSULATION TRANSFORMER AND KEY INPUT CIRCUIT HAVING THE SAME - An insulation transformer and a key input circuit having the same are disclosed. The insulation transformer includes: a core having a certain gap; and primary and secondary coils wound on the core. According to the insulation transformer, the operation deficiency of the insulation transformer can be reduced and thus the signal transmission efficiency can be improved. Also, the key input circuit including: an insulation transformer includes a core having a certain gap, and primary and secondary coils wound on the core; a microcomputer connected with the primary coil; and a key input unit connected with the secondary coil and including multiple resistors and switches. According to the key input circuit having the insulation transformer, the reliability of the operation of the key input circuit can be improved and user inconvenience that may be caused by an operation error can be prevented.12-23-2010
20110002146MULTIPLE OUTPUT SWITCHING POWER SOURCE APPARATUS - A multiple-output switching power source apparatus includes a control circuit to adjust a time for applying a DC voltage to a primary winding of a transformer by turning on/off a switching element Q01-06-2011
20110085357FLYBACK POWER SUPPLY WITH FORCED PRIMARY REGULATION - A flyback converter controller with forced primary regulation is disclosed. An example flyback converter controller includes a secondary control circuit to be coupled to a switched element coupled to a second winding of a coupled inductor of a flyback converter. The secondary control circuit is to be coupled across an output of the second winding to switch the switched element in response to a difference between an actual output value at the output of the second winding and a desired output value to force a current in a third winding of the coupled inductor that is representative of the difference between the actual output value at the output of the second winding and the desired output value. A primary control circuit is also included and is to be coupled to a primary switch coupled to a first winding of the coupled inductor. The primary control circuit is to be coupled to receive the current forced in the third winding by the secondary control circuit. The primary control circuit is coupled to switch the primary switch to regulate an output of the flyback converter coupled to the output of the second winding in response to the forced current.04-14-2011
20120243269Circuits and Methods for Controlling Power Converters Including Transformers - A circuit includes a transformer and a controller. The transformer includes a primary winding and a secondary winding, and operates in multiple switching cycles. A switching cycle includes a charging period and a discharging period. During the charging period, the transformer is powered by the input voltage and a current flowing through the primary winding increases. During the discharging period the transformer discharges to power the load and a current flowing through the secondary winding decreases. The controller includes a pin that receives a first feedback signal indicating the input voltage during the charging period and receives a second feedback signal indicating an electrical condition of the secondary winding during the discharging period. The controller generates a first control signal and a second control signal to regulate the input voltage and an output current flowing through the load, respectively.09-27-2012
20120243268Transformers and Methods For Constructing Transformers - Transformers and methods of constructing transformers are disclosed. In one embodiment, a method of constructing a transformer includes wrapping a first primary winding around a core, wrapping a secondary winding around the core, and wrapping a second primary winding around the core. The first primary winding traverses substantially an entire circumference of the core in a first circumferential direction. The secondary winding includes a first half and a second half. The first half traverses substantially the entire circumference of the core in the first circumferential direction, and the second half traverses substantially the entire circumference of the core in a second circumferential direction opposite the first circumferential direction. The second primary winding traverses substantially the entire circumference of the core in the second circumferential direction.09-27-2012
20110249474METHOD AND APPARATUS FOR POWER CONVERSION USING AN INTERLEAVED FLYBACK CONVERTER WITH ALTERNATING MASTER AND SLAVE BRANCHES - Embodiments of the present invention generally relate to power conversion and, more particularly, to a method and apparatus for performing power conversion using an interleaved flyback converter with alternating master and slave branches. The apparatus comprises a plurality of parallel connected flyback circuits; a controller is coupled to the switches within the flyback circuits to turn-on and turn-off the plurality of flyback circuits; a current monitor element at the output connected to the controller; a voltage monitor element connected to the controller; based on monitored current and voltage the controller controls the operation of flyback circuit; slave circuit only turn-on when the power is higher than a threshold value; the master and slave circuits are alternating to even the usage of the circuits.10-13-2011
20110149615METHOD AND APPARATUS FOR LIMITING MAXIMUM OUTPUT POWER OF A POWER CONVERTER - An example power converter includes an energy transfer element, a switch, a controller, and a current offset circuit. The controller is coupled to switch the switch between an ON state and an OFF state to regulate the output of the power converter. The controller is also adapted to terminate the ON state of the switch in response to a switch current flowing through the switch reaching a switch current threshold. An auxiliary winding of the energy transfer element is adapted to generate an auxiliary winding voltage that is representative of an input voltage of the power converter only during the ON state of the switch. The current offset circuit is coupled to the auxiliary winding to generate an offset current to flow through the switch in response to the auxiliary winding voltage, where an input current of the power converter is adjusted in response to the offset current.06-23-2011
20110149613FLYBACK CONVERTER UTILIZING BOOST INDUCTOR BETWEEN AC SOURCE AND BRIDGE RECTIFIER - A flyback converter utilizes a boost inductor coupled between a source of AC power and a bridge rectifier to provide power factor correction. A primary winding of the flyback transformer is coupled in series with a storage capacitor across the output of the bridge rectifier. A circuit, which includes a switching transistor, is also coupled across the output of the bridge rectifier to provide a low resistance path when the switch is closed. The cores of the boost inductor and the transformer are loaded with energy when the switch is closed. When the switch opens, the energy stored in the magnetic cores is transferred to the output via the transformer secondary winding and rectification circuitry.06-23-2011
20110002147SWITCHING POWER SUPPLY APPARATUS AND SEMICONDUCTOR DEVICE FOR SWITCHING POWER SUPPLY REGULATION - An off-period adjustment circuit 01-06-2011
20100302816SWITCHING MODE POWER SUPPLY WITH A SPECTRUM SHAPING CIRCUIT - In accordance with the teachings described herein, systems and methods are provided for a switching mode power supply. In one example, the switching mode power supply may include a transformer, a switching circuit and a switching control circuit. The transformer receives a DC input voltage on a primary winding and generates a DC output voltage on a secondary winding. The switching circuit, which may include a MOSFET switch, is coupled to the transformer and is configured to switch the transformer on and off. The switching control circuit generates a switching control signal to control the switching circuit in order to regulate the DC output voltage of the transformer. The switching control circuit is configured to generate the switching control signal as a function of a timing signal having a varying frequency, wherein the varying frequency of the timing signal causes a switching frequency of the switching circuit to vary over a period of time in order to reduce electromagnetic interference caused by the switching circuit.12-02-2010
20100254166METHOD AND APPARATUS FOR ON/OFF CONTROL OF A POWER CONVERTER - A power converter control method and apparatus is disclosed. An example power converter controller according to aspects of the present invention includes a feedback sampling circuit coupled to receive a feedback signal representative of an output of a power converter to generate feedback signal samples during enabled switching cycles. The power converter controller also includes a switch conduction control circuit coupled to the feedback sampling circuit. The switch conduction control circuit includes switch conduction enable circuitry coupled to enable or disable the conduction of a power switch during a switching cycle in response to the feedback signal samples. The switch conduction control circuit also includes switch conduction scheduling circuitry coupled to determine a varying number of future enabled and disabled switching cycles in response to the feedback signal samples from a present switching cycle and one or more past switching cycles.10-07-2010
20100061126System and method for a primary feedback switched mode power supply - A primary side controlled power converter having a voltage sensing means coupled to a transformer of the power converter and configured to provide a voltage feedback waveform representative of an output of the transformer is provided. A primary switching circuit operates to control energy storage of a primary side of the transformer. The primary switching circuit is operable during an on time and inoperable during an off time. The on and off time is switched at a system frequency. A feedback amplifier generates an error signal indicative of a difference between the voltage feedback waveform and a reference voltage. A sample and hold circuit samples the error signal at a periodic frequency during the off time. An error signal amplifier is configured to provide the sampled value to the primary switching circuit wherein the primary switching circuit controls the transformer and thereby regulates an output of the power converter.03-11-2010
20100039835SWITCHING POWER SOURCE APPARATUS - A switching power source apparatus has a controller generating a drive signal that controls an ON/OFF period of a switching element 02-18-2010
20110149614DUAL MODE FLYBACK CONVERTER AND METHOD OF OPERATING IT - A DC-DC converter includes a power switching device and a mode control logic circuit to control the power switching device and generate an ON-pulse. A flip-flop is configured to be set by the mode control logic circuit. A current mode comparator is configured to reset the flip-flop and to compare a signal based upon current flowing through the power switching device with a signal based upon an output voltage of the dual mode flyback DC-DC converter. A transformer is driven by the current mode comparator. The mode control logic circuit includes a timer starting when a gate driver control signal applied to the power switching device turns the power switching device off and configured to generate a pulse when an off time interval elapses, a zero current detector circuit configured to sense a voltage on the transformer and generate a pulse when the voltage drops below a trigger threshold, and a combinatory logic circuit configured to compare pulse signals generated by the timer and the zero current detector circuit and generate the ON-pulse based thereupon.06-23-2011
20110176338Electrical power adaptor with self-adjusting output voltage regulation - The present invention relates to an electrical power adaptor with self-adjusting output voltage regulation which comprises a switching power supply circuit for converting an alternate current into a direct current, and a power supply return circuit connecting with the switching power supply circuit. The switching power supply circuit comprises an EMI filter circuit, a full-bridge rectifier circuit, a switching transformer, a secondary rectification filter circuit, a PWM control circuit and an optocoupler feedback control circuit. The power supply return circuit comprises an output line, output adaptor and an MCU main control circuit. The MCU main control circuit is connected with the switching power supply circuit. The output adaptor is disposed with a signal resistor. The MCU main control circuit controls the output voltage of the switching power supply circuit according to the signal resistor of the output adaptor. The electrical adaptor of the present invention provides a wider range of output voltages with higher precision. Furthermore, by connecting a signal resistor to an output adaptor and altering feedback resistance of a feedback network according to feedback signals of the signal resistor, the signal resistor is not required to meet a very high standard of precision. The design of the present invention is safer and more personalized.07-21-2011
20110255309High-Speed Reflected Signal Detection for Primary-Side Controlled Power Converters - A controller for a power converter includes a clamping circuit, a switching circuit and a pulse generator. The clamping circuit is coupled to an input terminal of the controller for detecting a detection signal from a transformer. The switching circuit generates a switching signal to switch the transformer in response to the detection signal for regulating the power converter. A maximum level of the detection signal is clamped to be under a level of a threshold voltage during an off-period of the switching signal. Since the maximum level of the detection signal is clamped and the oscillating energy of the reflected signal is discharged, the speed of detecting the detection signal is increased. Therefore, the regulation of the primary-side controlled power converter can be improved accordingly.10-20-2011
20110261594POWER SUPPLY WITH INPUT FILTER-CONTROLLED SWITCH CLAMP CIRCUIT - An example power supply in accordance with the teachings of the present disclosure includes a switch, an energy transfer element, a controller, an input filter, and a switch clamp circuit. The energy transfer element is coupled to the switch and the controller is coupled to control the switch to regulate an output of the power supply. The input filter is coupled to receive an input voltage of the power supply and includes a first input filter capacitor coupled to a node and a second input filter capacitor coupled to the node. The switch clamp circuit is also coupled to the node to clamp a voltage across the switch in response to a voltage at the node.10-27-2011
20110058396FLYBACK-TYPE INVERTER CIRCUIT FOR NETWORK SUPPLY OR FOR NETWORK-INDEPENDENT OPERATION - An inverter circuit for supplying solar power or wind power to a network or for network-independent operation. The inverter circuit includes a minimum number of components and can therefore be kept very compact.03-10-2011
20110096572LOW POWER CONSUMPTION START-UP CIRCUIT WITH DYNAMIC SWITCHING - A start-up circuit in a switch-mode power converter that employs a Zener diode to provide a reference voltage to reduce the power consumption and the size of the start-up circuit. The start-up circuit also includes a coarse current source and a coarse reference voltage signal generator for producing current and reference voltage for initial startup operation of a bandgap circuit. The reference signal and current from coarse current source and the reference voltage signal generator are subject to large process, voltage and temperature (PVT) variations or susceptible to noise from the power supply, and hence, these signals are used temporarily during start-up and replaced with signals from higher performance components. After bandgap circuit becomes operational, the start-up receives voltage reference signal from the bandgap circuit to more accurately detect undervoltage lockout conditions.04-28-2011
20100195355SWITCHING POWER CONVERTER WITH LOAD IMPEDANCE DETECTION - In a switching power converter, no-load condition is detected based on a variety of parameters including the output current, primary current, transformer reset time, and switching period. Once the no-load condition is detected, the switching power converter enters stand-by mode, in which the reference voltage corresponding to the target regulated output voltage of the switching power converter is lowered to a low stand-by value or the switching power converter is shut down for a predetermined duration. As a result, power loss during the stand-by mode of the switching power converter can be reduced significantly.08-05-2010
20110188270CIRCUIT - A circuit comprising a power factor correction stage having a DC input, a ground input, a DC output and a ground output; a capacitor; a diode; and discharge means. A first terminal of the diode is connected to an input of the power factor correction stage, a second terminal of the diode is connected to the first plate of the capacitor; and the second plate of the capacitor is connected to the other input of the PFC stage. The discharge means is connected to the capacitor and is configured to discharge the capacitor such that it contributes to the output of the PFC stage when the level of a signal at the input of the PFC stage falls below a threshold value.08-04-2011
20110216558POWER FACTOR CORRECTION CONVERTER - A low-cost PFC converter capable of detecting an inductor current including a DC component and performing appropriate correction of a power factor with low loss includes a diode bridge that rectifies an AC voltage input from an AC input power supply Vac, a series circuit including an inductor and a switching element, a rectifying and smoothing circuit that is connected in parallel to the switching element and that includes a diode and a smoothing capacitor, and a digital signal processing circuit that performs on/off control on the switching element so that an input current input from the AC input power supply Vac has a similar waveform with respect to an AC voltage. A current flowing through the inductor during an off period of the switching element is detected using a current detecting resistor, and a decreased voltage of the current detecting resistor is sampled at the middle of the off period of the switching element, thereby detecting an average value of the input current.09-08-2011
20090268487CIRCUIT FOR OUTPUT VOLTAGE ERROR DETECT AND FEEDBACK IN SMPS - The present invention relates to an error information detection circuit and an error feedback circuit, which detect the error of an output voltage from a voltage induced to a winding. The circuit for detecting error information of an output voltage of a transformer from voltage induced to the feedback winding of the transformer and feeding back the error information includes a flyback period detection circuit (10-29-2009
20120039097METHOD AND APPARATUS FOR SENSING MULTIPLE VOLTAGE VALUES FROM A SINGLE TERMINAL OF A POWER CONVERTER CONTROLLER - An example controller for a power converter includes a switching control coupled to switch a power switch of the power converter to control a transfer of energy from an input of the power converter to an output of the power converter. A sensor is coupled to sample a single terminal of the controller during a portion of an off time of the power switch to output a signal representative of an output voltage of the power converter. The sensor is further coupled to sample the single terminal during a portion of an on time of the power switch to output a signal representative of a line input voltage of the power converter. The switching control is responsive to the sensor.02-16-2012
20120039096High Voltage Startup Circuit - In one embodiment, a startup circuit for a power supply is provided. The startup circuit comprises a resistance coupled between a voltage source and a first node. A first capacitor, coupled to the first node, is operable to be charged by current flowing through the resistance. A first transistor has an emitter, a base, and collector, wherein the collector is coupled to the voltage source and the base is coupled to the first node. A diac circuit. coupled to the emitter of the first transistor, is operable to fire to turn on the first transistor, thereby allowing discharge of the first capacitor through the base-emitter junction of the first transistor. A second capacitor is operable to be charged by current related to a discharge voltage resulting from the firing of the diac circuit. The second capacitor operable to store charge to provide VCC voltage to a controller of the power supply.02-16-2012
20110063878POWER-SUPPLY CONTROLLER - An embodiment of a controller for a power supply includes circuitry that is operable to allow the power supply to operate as follows. During a first portion of a supply period, a first current flows through a first winding of the power supply, through a second winding of the power supply, and to an output node of the power supply. And during a second portion of the supply period, a second current flows through the first winding, through a third winding of the power supply, and to the output node. Each of the first, second, and third windings may be non-electrically isolated from one or more of the other windings during one or more portions of the supply period. Furthermore, the first, second, and third windings may be magnetically coupled to one another. For example, in an embodiment, such a controller may be part of a DC-DC converter that may be more efficient, and that may have reduced interdependence between output-signal ripple and transient response, than a conventional buck converter.03-17-2011
20120057375METHOD AND APPARATUS FOR A FLYBACK POWER CONVERTER PROVIDING OUTPUT VOLTAGE AND CURRENT REGULATION WITHOUT INPUT CAPACITOR - A control circuit of a power converter according to the present invention comprises an output circuit, at least one input circuit and an input-voltage detection circuit. The output circuit generates a switching signal for regulating an output of the power converter in response to at least one feedback signal. The switching signal is coupled to switch a transformer of the power converter. The input circuit samples at least one input signal for generating the feedback signal. The input signal is correlated to the output of the power converter. The input-voltage detection circuit generates an input-voltage signal in response to the level of the an input voltage of the power converter. The input circuit will not sample the input signal when the input-voltage signal is lower than a threshold. The control circuit can eliminate the need of the input capacitor for improving the reliability of the power converter.03-08-2012
20120026757CONVERTER CONTROLLER - Provided is a converter controller capable of preventing destruction of an element such as an auxiliary switch by preventing operation interference between auxiliary circuits of respective phases in a multiphase soft switching converter. A duty threshold input unit receives, as an input, an obtained acceptable duty deviation value. A duty deviation computation unit judges whether or not the duty deviation between the phases does not exceed an acceptable duty deviation value. When the duty deviation between the phases exceeds the acceptable duty deviation value, the duty deviation computation unit corrects an adjusted U-phase duty ratio, adjusted V-phase duty ratio and adjusted W-phase duty ratio under the PID control rule, and outputs the resultant duty ratios to an FC converter control circuit. On the other hand, when the duty deviation between the phases does not exceed the acceptable duty deviation value, the duty deviation computation unit does not correct the adjusted U-phase duty ratio, adjusted V-phase duty ratio and adjusted W-phase duty ratio and outputs them to the FC converter control circuit.02-02-2012
20120155121SWITCH-MODE POWER SUPPLY AND APPARATUS FOR COMPENSATING INDUCTOR CURRENT PEAK - A switch-mode power supply (SMPS) is provided. When the switch power of the SMPS turns on, the inductor current of the SMPS may flow through an inductor current sensing circuit which then provides a sensing voltage. An apparatus for compensating the inductor current peak receives a reference voltage and the sensing voltage as inputs and outputs a compensation voltage. The compensation voltage is combined with the reference voltage and/or the sensing voltage and is provided to a first comparator. The result keep 06-21-2012
20110007529DC-TO-DC CONVERTER - The present invention includes: a plurality of switching elements connected in series and connected between two ends of a DC power supply; a first control circuit to alternately turn on and off the switching elements in response to a constant oscillation frequency signal; a series circuit including a primary winding of a transformer and a capacitor connected together in series, and being connected to a connecting point between the switching elements, and to an end of the DC power supply; a rectifying/smoothing circuit to rectify and smooth a voltage in a secondary winding of the transformer thereby to output a DC voltage; a control switching element connected to two ends of the primary or secondary winding of the transformer; and a second control circuit to control the DC voltage at a predetermined voltage by turning on and off the control switching element.01-13-2011
20120155120POWER SUPPLY UNIT AND AN INFORMATION PROCESSING APPARATUS - A power supply unit includes input terminals to which alternating current power is supplied, a rectifier circuit configured to rectify the alternating current power supplied from the input terminals, a capacitor configured to smooth the alternating current power rectified by the rectifier circuit, a primary transformer winding and a switching element connected in series between first and second terminals of the capacitor, a secondary transformer winding coupled to the primary transformer winding, output terminals connected to the secondary transformer winding, and a snubber circuit connected parallel to the switching element. The snubber circuit includes a parallel circuit having a first capacitor and a second capacitor connected in parallel, and a resistor connected in series with the parallel circuit.06-21-2012
20110090718SWITCHING POWER SUPPLY DEVICE - The present invention has as an object to introduce a switching power supply device having a simple circuit structure and controlling a secondary-side output voltage in a highly-accurate and stable manner. The switching power supply device includes: an auxiliary winding resetting detecting circuit which is connected to the auxiliary winding, monitors an auxiliary winding voltage pulse signal generated on the auxiliary winding, and generates an auxiliary winding reset signal indicating timing of which a secondary-side current finishes flowing into the secondary winding and the auxiliary winding voltage signal drops; and an auxiliary winding voltage sample hold circuit which holds the auxiliary winding voltage signal. The auxiliary winding voltage sample hold circuit includes a delaying circuit which delays the auxiliary winding voltage signal, and holds the auxiliary winding voltage pulse signal delayed by the delaying circuit with the timing indicated by the auxiliary winding reset signal.04-21-2011
20110103101INTEGRATED CONTROL CIRCUIT FOR CONTROLLING A SWITCHING POWER SUPPLY, SWITCHING POWER SUPPLY INCORPORATING THE SAME, AND A METHOD OF CONTROLLING A SWITCHING POWER SUPPLY - An integrated control circuit for controlling a switching power supply, a switching power supply incorporating the same, and a method of controlling the switching power supply, where the control IC includes a current comparator that detects current flowing through a switching device, a flip-flop circuit that controls the ON-period of the switching device, an averaging circuit that converts the peak load current value to a time-average, a comparator that detects an overloaded state from the load current, a delay circuit that sets a time from detecting the overcurrent state to stopping the switching operation, a latch circuit that stops the switching operation for a period of time, a first reference voltage supply used in the current comparator, which has a higher voltage value than a second reference voltage supply used in the comparator.05-05-2011
20120250363Interleaved Power Converter and Controller Therefor - Disclosed is an interleaved power converter for converting a DC voltage source into a DC voltage output.10-04-2012
20120250364FLYBACK CONVERTER WITH FORWARD CONVERTER RESET CLAMP - A power supply includes a first power converter having a first transformer coupled to an input of the power supply and to a first output of the power supply. A clamp reset circuit is coupled to the first transformer. The clamp reset circuit includes a capacitor coupled to the first power converter and a Zener diode coupled to the capacitor. A second power converter is coupled to the clamp reset circuit. The second power converter includes a second transformer coupled to the clamp circuit and to a second output of the power supply. The capacitor is coupled to store energy received from the first power converter and the second power converter. The Zener diode is coupled to prevent the energy received from the first power converter and the second power converter from exceeding a threshold. The Zener diode limits voltage on the capacitor.10-04-2012
20100246216SWITCH MODE POWER SUPPLY CONTROLLERS - This invention relates to SMPS controllers employing primary side sensing. We describe a system for identifying a knee point in a sensing waveform, at which the output voltage of the SMPS may be sampled accurately on the primary side. The system identifies the knee point, broadly speaking, by tracking a portion of a power transformer voltage waveform, and samples the voltage waveform at the knee point to determine the SMPS output voltage. In preferred embodiments this technique is implemented using a circuit akin to a decaying peak detector, providing a timing signal indicating detection of the knee point. Sample/hold and error amplifier circuits may be employed to achieve output voltage regulation.09-30-2010
20120163040REDUCING VOLTAGE STRESS IN A FLYBACK CONVERTER DESIGN - Disclosed is flyback converter having a controller that performs a startup switching process when the flyback converter is powered up, and then performs normal switching afterward. The controller includes a pulse generator to generate a control signal for normal switching. During startup switching, the controller may generate a control signal by output every N06-28-2012
20120134181GATE DRIVING POWER SUPPLY SYSTEM AND INVERTER CONTROL CIRCUIT - A primary power supply input can be supplied to each of gate driving units through individual transformers, respectively, from power supply terminals. One end of a primary winding of each of the transformers can be connected to the power supply terminal by power supply lines. In addition, the other end of each of the primary windings can be connected to one another by common connection lines to be further connected to a drain terminal of a MOSFET for controlling a current flowing in each of the primary windings. A gate power supply control circuit, to which an output current detected by an auxiliary winding of the transformer is fed back, can control a duty ratio for the on-off control of the MOSFET.05-31-2012
20120170326Primary-side controlled power converter with an RC network and Method thereof - This invention provides a primary-side controlled power converter comprising: an RC network coupled to an auxiliary winding of a transformer of the primary-side controlled power converter to detect a reflected voltage of the transformer for generating a reflected signal, and a controller coupled to the RC network to receive the reflected signal for generating a switching signal; wherein the RC network develops a zero to provide a high-frequency path for shortening a rising time and a settling time of the reflected signal.07-05-2012
20120170328Multimodal LED Power Supply With Wide Compliance Voltage and Safety Controlled Output - A power supply for a non-linear load such as a light emitting diode load uses a voltage dynamic of a fly-back topology to correct for a rippling of an unfiltered rectified line voltage. Efficiency is optimized by utilizing a magnetic core bi-directionally. A transformer has two primaries 07-05-2012
20120170327APPARATUS AND METHOD FOR DETECTING A CHANGE IN OUTPUT VOLTAGE OF AN ISOLATED POWER CONVERTER - An output voltage sensor for use in a power converter controller includes a first pulse sampler circuit coupled to receive a feedback signal representative of an output of a power converter. The first pulse sampler circuit is coupled to capture a first peak voltage representative of a second peak of a ringing voltage of the feedback signal at a first time in the feedback signal. A second pulse sampler circuit is coupled to receive the feedback signal representative of the output of the power converter. The second pulse sampler circuit is coupled to capture a second peak voltage representative of the second peak of the ringing voltage of the feedback signal at a second time in the feedback signal. The output voltage sensor is coupled to output a change signal to a drive circuit of the power converter controller in response to the first and second peak voltages.07-05-2012
20120212980POWER SUPPLY APPARATUS AND IMAGE FORMING APPARATUS - A power supply apparatus supplies regulated power to an external apparatus. A power switch is turned on to receive AC power and turned off not to receive the AC power. The AC power is rectified by a rectifying section and is switched by a switching section into switched DC power which is smoothed by a rectifying/smoothing section. Upon reception of an alarm signal, the power disconnecting section stops sending the switched DC power to the rectifying/smoothing section. If the AC switch is turned off and then back on again after stopping sending the switched DC power to the smoothing section, the power disconnecting section allows receiving of the AC power only a time after turn-off of the power switch. Upon reception of an auto-off signal indicative of an idle state of the external apparatus, an auto-off section does not send the switched DC power to the rectifying/smoothing section.08-23-2012
20120230063SELF-EXCITED SWITCHING POWER SUPPLY CIRCUIT - There is provided a self-excited switching power supply circuit. A cycle control capacitor is charged with a flyback voltage generated in a feedback winding of a transformer during OFF operation period in which an exciting current does not flow in a primary winding of the transformer. An OFF control capacitor the charging speed of which changes ON operation period is charged with the charging voltage of the cycle control capacitor during the ON operation period in which an exciting current flows in the primary winding. The charging voltage of the cycle control capacitor is changed with a periodic cycle Tc sufficiently longer than an oscillation cycle To to make the oscillation cycle To of continuous oscillating operation variable based on the periodic cycle Tc. As a result, the frequency of a harmonic is distributed.09-13-2012
20120176821Startup Circuit and Input Capacitor Balancing Circuit - In one embodiment, an input capacitor balancing circuit for a power supply is provided. The circuit includes an input capacitance operable to filter input power for the power supply. The input capacitance has a first capacitor and a second capacitor coupled in series between an input voltage and a first node. A voltage divider circuit is coupled to the input voltage and operable to generate a divided voltage therefrom. A buffer circuit is operable to receive the divided voltage and, if the first capacitor and the second capacitor are not balanced, to provide current to the input capacitance to balance the first capacitor and the second capacitor.07-12-2012
20120176819ADAPTIVELY CONTROLLED SOFT START-UP SCHEME FOR SWITCHING POWER CONVERTERS - A switching power converter provides regulated voltage to a load according to a desired regulation voltage. The switching power converter includes a transformer coupled to a switch and a switch controller for generating a control signal to control switching. The switch controller monitors a sensed voltage representing the output voltage of the switching power converter. The switch controller controls switching of the switch to operate the switching power converter in a continuous conduction mode while the sensed output voltage indicates that the output voltage is less than a first threshold voltage. The switch controller controls switching of the switch to operate the switching power converter in a discontinuous conduction mode while the sensed output voltage is above the first threshold voltage.07-12-2012
20120218786METHOD AND APPARATUS FOR IMPLEMENTING AN UNREGULATED DORMANT MODE WITH AN EVENT COUNTER IN A POWER CONVERTER - An example power converter includes an energy transfer element, a switch, and a control circuit. The control circuit includes a drive signal generator and an unregulated dormant mode control circuit. The unregulated dormant mode control circuit renders dormant the drive signal generator thereby ceasing the regulation of the output by the drive signal generator when the energy requirement of the one or more loads falls below a threshold for more than a first period of time. The drive signal generator is unresponsive to changes in the energy requirements of the one or more loads when dormant. The unregulated dormant mode control circuit powers up the drive signal generator after a second period of time has elapsed, such that the drive signal generator is again responsive to changes in the energy requirement of the one or more loads after the second period of time has elapsed.08-30-2012
20120218785Three-Level Active Neutral Point Clamped Zero Voltage Switching Converter - A main circuit of a three-level active neutral point clamped voltage source converter having a pair of additional main switches provides two paths between an output node and a neutral point in which one of the paths involves only switches of an inner pair of switches that are operated at a high frequency. An auxiliary circuit operating at a high frequency for only a brief period during each high frequency switching cycle selects the path involving only the inner switches and provides operation with zero voltage switching and avoids reverse recovery of diodes connected antiparallel with the main and additional main switches. Accordingly, turn-on switching losses in the main switches is avoided and the voltage source converter can be operated at increased frequency to allow reduction in size of magnetic components and full potential power transfer to be achieved.08-30-2012
20120257422DC/DC CONVERTER AND ELECTRIC GENERATING SYSTEM USING SOLAR CELL HAVING THE SAME - Disclosed herein is an electric generating system using a solar cell, including: a DC/DC converter that converts output voltage generated from a solar cell into DC voltage and has a converter switching device; a snubber device that has a snubber switch clamping voltage applied to the converter switching device; and a control device that detects the voltage applied to the converter switching device and controls an operation of the snubber switch according to a detected voltage level applied to the converter switching device, thereby increasing the efficiency of the electric generating system using a solar cell while reducing switching loss and conduction loss.10-11-2012
20120188799METHOD AND APPARATUS FOR INCREASING THE POWER CAPABILITY OF A POWER SUPPLY - One example controller for a power supply includes an oscillator, a drive signal generator, and a restart circuit. The oscillator generates a clock signal and the drive signal generator controls switching of a switch to regulate an output of the power supply in response to the clock signal. The restart circuit generates a restart signal in response to a current through the switch and in response to an absolute maximum on time period. The oscillator generates the clock signal to have a fixed maximum frequency in response to the restart signal indicating that the current through the switch reaches a current limit threshold within the absolute maximum on time period. The oscillator also generates the clock signal to have a variable minimum frequency in response to the restart signal indicating that the current through the switch has not reached the current limit threshold within the maximum on time period.07-26-2012
20120188798SWITCHING POWER SOURCE AND IMAGE FORMING APPARATUS HAVING SWITCHING POWER SOURCE - In a converter, when an output voltage is set to a low voltage, a switching element is turned on according to a pulse voltage induced in an auxiliary winding having the same winding direction as that of a primary winding of a transformer.07-26-2012
20120081929High Efficiency and Low Cost High Voltage Power Converter - A low cost, high efficiency, high voltage DC to DC power converter that operates from batteries to provide support to products using Electric Field Effect Technology to generate aerosols.04-05-2012
20120081928Flyback Converter with an Adaptively Controlled Rectifier Arrangement - A flyback converter includes input terminals and output terminals. A transformer with a first winding and a second winding are inductively coupled. A first switching element is connected in series with the first winding and a first series circuit with the first switching element, the first winding being coupled between the input terminals. A rectifier arrangement is connected in series with the second winding and a second series circuit with the rectifier arrangement, the second winding being coupled between the output terminals. The rectifier arrangement includes a second switching element. A control circuit is configured in one drive cycle to switch on the first switching element for a first time period. After the first time period the second switching element is switched on for a second time period. A third time period is determined between an end of the second time period and the time at which the transformer assumes a predetermined transformer state. The control circuit is further configured to adapt the second time period to be applied in a subsequent drive cycle dependent on the second time period applied in the one drive cycle and the third time period is determined in the one drive cycle.04-05-2012
20110122658POWER CONVERTER USING ENERGY STORED IN LEAKAGE INDUCTANCE OF TRANSFORMER TO POWER SWITCH CONTROLLER - The power converter includes a transformer that is coupled or decoupled from a power source by a switch controlled by a switch controller. The transformer includes a first primary winding coupled to a secondary winding. The energy stored in the leakage inductance of the first primary winding is received by a second primary winding. The energy received by the second primary winding is provided to the switch controller to power the switch controller. The second primary winding is wound adjacent to the first primary winding to receive more energy from the first primary winding.05-26-2011
20080298095Light-load efficiency improving method and apparatus for a flyback converter - A flyback converter has a controller to switch a power switch so as to convert an input voltage to an output voltage for a load by monitoring an output voltage dependent signal and a current sensing signal derived from a current flowing through the power switch, a light-load efficiency improving apparatus monitors the load and a supply voltage provided for the controller to selectively clamp the output voltage dependent signal when the load is lower than a first threshold value and the supply voltage is lower than a second threshold value, so as to increase the supply voltage.12-04-2008
20110222319SWITCHING POWER SUPPLY - A switching power supply includes a first auxiliary power supply for causing a first auxiliary winding of a transformer to induce voltage by ON/OFF control of a switching element connected to a primary winding of the transformer. The voltage induced by the first auxiliary winding charges a capacitor in the first auxiliary power supply. The switching power supply also includes a control circuit for starting and stopping the ON/OFF control of the switching element by comparing a voltage of the capacitor with a first threshold value, an activation circuit for charging the capacitor with voltage from the power supply input to the switching power supply, and a determination unit for determining a lifespan of the switching power supply based on the voltage of the capacitor after the voltage of the capacitor becomes greater than or equal to the first threshold value.09-15-2011
20110235371Constant-current circuit capable of voltage compensation and zero-voltage switching - The present invention is to provide a constant-current circuit capable of voltage compensation and zero-voltage switching, wherein the constant-current circuit is a single-switch isolated flyback converter and includes a control circuit, a sensing resistor, a transformer, a voltage divider, and a primary-side power switch. The control circuit obtains information related to a primary-side current of the transformer by way of the sensing resistor and obtains a compensation signal from an input voltage by way of the voltage divider, so as to control the primary-side power switch accordingly. Due to a compensating effect of the compensation signal, a peak voltage resulting from the sensing resistor is adjusted to a reference voltage through adding the compensation signal thereto, thereby enabling the constant-current circuit to generate a constant output current over a wide range of input voltage.09-29-2011
20100232186SWITCHING POWER SUPPLY DEVICE - A switching power supply device includes a transformer, a switching unit which is connected with a primary winding of the transformer and configured to switch a current flowing to the primary winding, a start unit configured to start the switching unit, a voltage drop unit configured to lower output voltage from a secondary winding of the transform, and a current control unit configured to control an amount of a current flowing in the start unit when the switching unit is in an off state by lowering output voltage by the voltage drop unit.09-16-2010
20100232185POWER SUPPLY MODULE - A power supply module includes an AC/DC converter, a voltage transforming circuit, a feedback circuit, and a detecting circuit. The AC/DC converter is used for converting the input AC voltage to a primary DC voltage. The voltage transforming circuit is used for transforming the primary DC voltage to the first DC voltage. The feedback circuit is used for sampling the first DC voltage to generate a feedback signal. The detecting circuit is used for detecting if the power supply module is powered on, and generating a first voltage when detecting that the power supply module is powered on. Wherein the voltage transforming circuit maintains the first DC voltage at a first predetermined value according to the feedback signal, the feedback circuit increases a magnitude of the feedback signal according to the first voltage.09-16-2010
20110255310METHOD AND APPARATUS FOR IMPLEMENTING AN UNREGULATED DORMANT MODE WITH AN EVENT COUNTER IN A POWER CONVERTER - A method for controlling an output of a power converter includes generating a drive signal with a control circuit, entering a dormant mode of operation that includes powering down the control circuit if a flow of energy to an output of the power converter is less than a threshold value for more than a first period of time, and powering up the control circuit after it is in the dormant mode of operation for a second period of time.10-20-2011
20120087156METHOD AND APPARATUS FOR LIMITING MAXIMUM OUTPUT POWER OF A POWER CONVERTER - An example power converter includes an energy transfer element, a switch, a controller, and a current offset circuit. The controller switches the switch between an ON state and an OFF state to regulate the output of the power converter and is adapted to terminate the ON state of the switch in response to a switch current flowing through the switch reaching a switch current threshold. The current offset circuit is coupled to the input to be directly powered from an input voltage of the power supply. The current offset circuit generates an offset current to flow through the switch only during the ON state of the switch in response to a magnitude of the input voltage. The input current of the power converter is adjusted in response to the offset current.04-12-2012
20120092902PHASE ANGLE MEASUREMENT OF A DIMMING CIRCUIT FOR A SWITCHING POWER SUPPLY - An example controller for a switched mode power supply includes a zero-crossing detector and a drive signal generator. The zero-crossing detector is coupled to generate a zero-crossing signal representative of a phase angle of a dimmer output voltage for a half line cycle of the power supply. The drive signal generator controls switching of a switch to regulate an output of the power supply in response to a feedback signal representative of the output. The drive signal generator further controls switching of the switch to adjust dimming of the output of the power supply in response to the phase angle indicated by the zero-crossing signal.04-19-2012
20080298094Method and apparatus to control two regulated outputs of a flyback power supply - A flyback power supply method and apparatus is disclosed. An apparatus according to aspects of the present invention includes an energy transfer element having a primary winding and first and second output windings. The first and second output windings are coupled to produce first and second output values, respectively. A primary switch is coupled to the primary winding. A control circuit is coupled to the primary switch to regulate a sum of the first and second output values. A steering circuit having first and second output switches is also included. The first and second output switches are coupled to the first and second output windings, respectively, to regulate a ratio of the first output value to the second output value. The first output switch is coupled to block current through the first output winding and the second output switch is coupled to block current through second output winding. At least one of the first and second output switches is coupled to be closed when the primary switch is opened.12-04-2008
20100202164SWITCHING POWER CONVERTER FOR SUPPRESSING COMMON MODE NOISE - The present invention discloses a switching power converter with low common mode noise. The switching power converter comprises at least a switch with at least a terminal wherein said switch turning on and off alternatively which generates a plurality of noise voltages, and the noise voltage having a jump point and a static point wherein the jump point is one of said inductive component terminals, the capacitive component terminals and the second and third terminal of the switch; and an additional impedance connected between the static point and the jump point of different noise voltage to neutralize common noise current. In addition, another switching power converter having primary side and secondary side can be used to reduce the common mode noise by adding some additional impedance between the static points and jump points of the primary side and secondary side.08-12-2010
20100202163FLYBACK POWER CONVERTERS - A dual-switch flyback power converter includes a control circuit to generate a switching signal. A high-side driving circuit includes a pulse generation circuit. The pulse generation circuit generates a pulse-on signal and a pulse-off signal to control two transistors in response to the switching signal. The two transistors further respectively provide a level-shift-on signal and a level-shift-off signal to a comparison circuit to enable/disable a high-side driving signal. Without using a charge pump circuit to power the high-side driving circuit, a floating winding of a transformer is utilized to provide a floating voltage to power the high-side driving circuit, which reduces the cost of the dual-switch flyback power converter and ensures a sufficient high-side driving capability of the high-side driving circuit.08-12-2010
20120140529Energy Recirculation and Active Clamping to Improve Efficiency of Flyback or Push Pull DC to DC Converters - The present invention is a new circuit topology to improve the efficiency of a flyback or push-pull converter or any other DC/DC converter that incorporates a transformer and whose switching device's active node (drain for MOSFETs and collector for IGBTs) has no direct energy releasing path to the power supply. The present invention uses an auxiliary DC/DC converter separate from the main DC/DC converter to reroute the parasitic energy stored in the transformer's or inductor's leakage inductance, allowing for the output of the main DC/DC converter to be augmented with the energy that would otherwise be lost. The energy stored in the leakage inductance is converted and redirected to either the load side or the power supply side of the main DC/DC converter in a series or a parallel configuration. The present invention significantly increases the overall efficiency of the system by eliminating the power loss.06-07-2012
20110157923CIRCUITS AND METHODS FOR CONTROLLING POWER CONVERTERS INCLUDING TRANSFORMERS - A power converter includes a transformer operated in multiple switching cycles. At least one switching cycle includes a charging period, a discharging period, and an adjusting period. The transformer has a primary winding coupled to a power source and a secondary winding coupled to a load. During the charging period the transformer is powered by the power source and a current flowing through the primary winding increases. During the discharging period the transformer discharges to power the load and a current flowing through the secondary winding decreases. A ratio of a duration of the discharging period to a total duration of the charging period, the discharging period and the adjusting period is constant.06-30-2011
20110157922PRIMARY SIDE SENSING FOR ISOLATED FLY-BACK CONVERTERS - A switching voltage regulator samples signals corresponding to a flyback voltage on an auxiliary winding on a primary side of the switching voltage regulator. The flyback voltage functions as feedback from the output voltage on the secondary side. On detection of presence of the flyback voltage, samples corresponding to the flyback voltage are stored until the flyback voltage falls below a threshold voltage. A history of N samples of the flyback voltage is thus maintained. A sample older than the most recently stored sample is used to generate control for generation of the output voltage of the switching voltage regulator. Use of the older sample ensures that the flyback voltage sample used is one that is close to, but before the current in the secondary winding goes to zero.06-30-2011
20130021828INTEGRATED ON-TIME EXTENSION FOR NON-DISSIPATIVE BLEEDING IN A POWER SUPPLY - An example controller for a switched mode power supply includes a comparator, a drive logic, and an on-time extension block. The comparator has an output indicating whether the current through a switch of the power supply exceeds a zero-crossing current threshold. The drive logic is to generate a drive logic output signal in response to the current sense signal and in response to a feedback signal, where the drive logic output signal is representative of an on-time of the switch to regulate the output of the power supply. The on-time extension block is coupled to control switching of a switch and to extend the on-time until the output of the comparator indicates that the current sense signal reaches the zero-crossing current threshold or until the on-time of the switch reaches a zero-crossing time threshold.01-24-2013
20120243267APPARATUS AND METHOD FOR EFFICIENT DC-TO-DC CONVERSION THROUGH WIDE VOLTAGE SWINGS - A DC-to-DC converter includes two or more inductors coupled to a common core and two or more active switches, where at least one active switch is in an input current path. A controller operates the two or more active switches such that a DC input is driven through one or more of the two or more inductors to implement a power conversion operation.09-27-2012
20130114310Power Supply Control Circuit and method for sensing voltage in the power supply control circuit - The present invention discloses a power supply control circuit, the power supply providing an output voltage to an output terminal from an input terminal through a transformer having a primary winding and a secondary winding, the power supply control circuit comprising: a power switch electrically connected with the primary winding; a switch control circuit controlling the power switch; and a sensing circuit supplying an output signal to the switch control circuit according to voltage signals obtained from two sides of the primary winding, wherein the sensing circuit includes a setting circuit for deciding the output voltage according to a reference signal. The present invention also relates to a voltage sensing method in the power supply control circuit.05-09-2013
20130100713SWITCHING POWER CONVERSION CIRCUIT AND POWER SUPPLY USING SAME - A switching power conversion circuit having a two-stage power circuit topology and capable of performing power factor correction is disclosed. In a case that the electrical energy of the switching power conversion circuit needs not to be provided to the system circuit, for example the load and the electronic device fails to be operated, the switching power conversion circuit will be adaptively disabled. As a consequence, the switching power conversion circuit could achieve a power-saving purpose. Moreover, the switching power conversion circuit could be applied to a power supply. When the electronic device is not in use, the power supply has reduced power consumption, thereby achieving a power-saving purpose.04-25-2013
20130100710ACTIVE SURGE PROTECTION IN A POWER SUPPLY - A surge protection module is disclosed. An example surge protection module includes a first terminal coupled to a first output terminal of a rectifier of a power supply. A second terminal is coupled to a first input terminal of a switching converter of the power supply. A third terminal is coupled to a second output terminal of the rectifier and a second input terminal of the switching converter. A variable resistance circuit is coupled between the first and second terminals. A control circuit is coupled between the first and third terminals and coupled to control the variable resistance circuit. A resistance of the variable resistance circuit is responsive to a magnitude of a voltage between the first and third terminals.04-25-2013
20130100712POWER SOURCE DEVICE AND IMAGE FORMING APPARATUS - A power source device that outputs a DC voltage includes a rectification unit configured to rectify an input pulse voltage, a voltage-current conversion unit disposed on a side where the pulse voltage is input into the rectification unit, a current-voltage conversion unit configured to convert a current from the voltage-current conversion unit into a voltage, and a comparison unit configured to compare the voltage from the current-voltage conversion unit with a reference voltage. An operation of the rectification unit is controlled based on an output from the comparison unit.04-25-2013
20130100711Switching Circuit - A switching circuit (04-25-2013
20110267846APPARATUS AND METHOD FOR SENSING OF ISOLATED OUTPUT - A controller for use in a power converter providing sensing of an isolated output is disclosed. An example controller includes a current controller to be coupled to an energy transfer element and an input of the power converter. A control circuit is included that generates a mode select signal coupled to be received by the current controller. A first, second or third current is enabled in the current controller in response to a selection of a first, second or third mode of operation, respectively, of the current controller by the control circuit. The first current is substantially zero, the second current is greater than the third current and the third current is greater than the first current. A first feedback circuit is coupled to the control circuit and is coupled to generate a first feedback signal representative of an output of the power converter during the first mode of operation after a period of operation of the second mode of operation of the current controller. A second feedback circuit is coupled to the control circuit and is coupled to generate a second feedback signal representative of the output of the power converter during the first mode of operation after a period of operation of the third mode of operation of the current controller. The control circuit is coupled to control selections of the first, second or third modes of operation in response to the first and second feedback signals to control a transfer of energy from the input of the power converter to the output of the power converter.11-03-2011
20130128625APPARATUS AND METHOD FOR SENSING OF ISOLATED OUTPUT - A power converter includes a current controller coupled to an energy transfer element to selectively enable a first, second or third current in the current controller. The first current is substantially zero, the second current is greater than the third current, and the third current is greater than the first current. The third current only partially discharges a capacitance coupled to the energy transfer element and the current controller. A control circuit is to be coupled to the current controller to selectively enable the first, second or third current in the current controller. A first feedback circuit is coupled to generate a first feedback signal while the first current is enabled by the current controller after a full discharge pulse. A second feedback circuit is coupled to generate a second feedback signal while the first current is enabled in the controller after a partial discharge pulse.05-23-2013
20130148385ZERO VOLTAGE SWITCHING IN FLYBACK CONVERTERS WITH VARIABLE INPUT VOLTAGES - The disclosed embodiments provide a system that operates a flyback converter. During operation, the system senses an input voltage for the flyback converter. Next, the system uses the input voltage to determine a negative peak current that enables zero voltage switching for a primary switch in the flyback converter. Finally, the system uses the negative peak current to perform the zero voltage switching for the primary switch based on the input voltage, wherein the negative peak current reduces a power loss of the flyback converter.06-13-2013
20130148386SWITCHING REGULATOR - A switching regulator can include a transformer having a primary winding and a secondary winding, a switching circuit including a switching element that is connected in series to the primary winding, the series-connected circuit of the switching element and the primary winding being connected in parallel to a DC power supply and a rectifying circuit connected to the secondary winding. The switching regulator can also include a control circuit to control switching of the switching element to generate DC output voltage from the DC power supply, the DC output voltage being insulated from the DC power supply, an output voltage detecting circuit including a photo-coupler for insulated detection of the DC output voltage, the photo-coupler having a photo-transistor and a load quantity detector for detecting a state in which power consumption in the load connected to the DC output has reached a predetermined value.06-13-2013
20110255308SYSTEM, MODULE, AND METHOD FOR CONSTANT CURRENT CONTROLLING OF POWER CONVERTER - A system, a module, and a method for constant current controlling of a power converter are disclosed. The constant current controlling system includes a power converter and a constant current controlling module. The power converter has a transformer and a switching unit. The switch unit is coupled with the primary coil of the transformer. The constant current controlling module is coupled with the transformer and the switching unit, for generating a discharge time and detecting a current waveform signal, before generating a control signal in order to adjust the duration of the switching period of the switching unit to ensure that an output current of the power converter may remain substantially the same.10-20-2011
20120275198TRANSITION MODE CHARGE CONTROL FOR A POWER CONVERTER - One embodiment relates to power conversion system. The system includes a converter configured to convert an input voltage to an output voltage, the converter comprising at least one switch that is controlled in response to an activation signal to provide current through an inductor. A transition mode controller is configured to provide the activation signal based on a measure of charge derived from current through the switch and based on the current through the inductor.11-01-2012
20100315843METHOD OF DETECTION FOR OUTPUT SHORT CIRCUIT OF A FLYBACK POWER SUPPLY - Disclosed are methods of detection for output short circuit of a flyback power supply, which detect the current sense signal provided by a current sense resistor serially connected to a power switch of the flyback power supply, and thus quickly identify whether or not the flyback power supply suffers output short circuit.12-16-2010
20100315842DRIVE CIRCUIT FOR SEMICONDUCTOR SWITCHING ELEMENT - A drive circuit of first and second switches includes a first series circuit having a capacitor and a primary winding of a transformer and connected to both ends of a pulse signal generator, a first secondary winding of the transformer to apply a voltage to a control terminal of the first semiconductor switch based on the pulse signal, the first secondary winding being wound in a direction opposite to the primary winding, a second secondary winding of the transformer to apply a voltage to a control terminal of the second semiconductor switch based on the pulse signal, the second secondary winding being wound in the same direction to the primary winding, and a third semiconductor switch that turns on when the pulse signal is stopped, to shorten an ON period of the first semiconductor switch.12-16-2010
20100315841SEMICONDUCTOR DEVICE AND SWITCHING POWER SUPPLY APPARATUS - A switching power supply apparatus includes: a turn-on control circuit which generates a turn-on signal; a feedback control circuit which generates a reference voltage V12-16-2010
20120281438SYSTEMS AND METHODS FOR CONSTANT CURRENT CONTROL WITH PRIMARY-SIDE SENSING AND REGULATION IN VARIOUS OPERATION MODES - System and method for regulating a power converter. The system includes a first signal processing component configured to receive at least a sensed signal and generate a first signal. The sensed signal is associated with a primary current flowing through a primary winding coupled to a secondary winding for a power converter. Additionally, the system includes a second signal processing component configured to generate a second signal, an integrator component configured to receive the first signal and the second signal and generate a third signal, and a comparator configured to process information associated with the third signal and the sensed signal and generate a comparison signal based on at least information associated with the third signal and the sensed signal.11-08-2012
20130188400ENHANCED FLYBACK CONVERTER - A DC/DC flyback converter that exhibits reduced switch and transformer voltage stresses in comparison to known flyback converters. The flyback converter also employs soft switching. Embodiments of such flyback converters may be used, without limitation, in electric vehicles and hybrid electric vehicles. A front-stage of the flyback converter comprises a DC/AC step-down circuit that may be separately used for various purposes.07-25-2013
20120020122LOSSLESS COMMUTATION DURING OPERATION OF A POWER CONVERTER - A method for operating a DC-DC converter. The method comprises: matching, based on a turns ratio of a transformer of the DC-DC converter, a primary side capacitance of the DC-DC converter and a secondary side capacitance of the DC-DC converter to result in a matched capacitance; and operating the DC-DC converter with at least one operating parameter set to cause a primary current to oscillate between a peak value and zero such that a valley of the primary current coincides with a zero crossing of a secondary switching element voltage.01-26-2012
20130194835FLYBACK CONVERTER WITH FORWARD CONVERTER RESET CLAMP - A power supply includes a forward converter having a first transformer coupled to an input of the power supply and to a first voltage output. The power supply also includes a separate flyback converter having a second transformer that is coupled to the input and to a second voltage output. A clamp reset circuit is coupled to the first transformer and to the second transformer. The clamp reset circuit includes a capacitor and a voltage limiting element. The voltage limiting element is coupled to prevent energy received at the capacitor from both the power converters from exceeding a threshold. The voltage limiting element limits a voltage on the capacitor.08-01-2013
20130201729LOW-VOLUME PROGRAMMABLE-OUTPUT PFC RECTIFIER WITH DYNAMIC EFFICIENCY AND TRANSIENT RESPONSE OPTIMIZATION - The present invention is a system, apparatus and method of a PFC rectifier having a programmable output voltage that does not incur a drastic penalty in the overall size or volume of the device, or a significant degradation in efficiency. The PFC rectifier of the present invention may incorporate a two-stage solution for output voltage regulation. The present invention provides a topology of a small-size/volume PFC rectifier with a variable (i.e. programmable) output voltage and a complementary control method. The two-stage system of the present invention incorporates a smaller and lower cost capacitor than the bulky size and costly energy storage capacitors required in conventional prior art. The present invention also achieves tight output regulation. The two-stage topology of the present invention further achieves on-line efficiency optimization and significantly reduces the volume of the downstream stage over the prior art examples through dynamic adjustment of the downstream stage supply voltage.08-08-2013

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