| SYSTEM GENERAL CORP. Patent applications |
| Patent application number | Title | Published |
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| 20120106205 | POWER SUPPLY WITH OPEN-LOOP PROTECTION AND SHORT-CIRCUIT PROTECTION - The power supply according to the present invention comprises a transformer, a power switch, a signal generating circuit, an on-time detection circuit, and a delay circuit. The transformer receives an input voltage and generates an output voltage. The power switch switches the transformer for regulating the output voltage. The signal generating circuit generates a switching signal for controlling switching of the power switch. The on-time detection circuit detects an on-time of the power switch and generates a short-circuit signal. The delay circuit counts to a first delay time or to a second delay time in response to a feedback signal of the power supply and the short-circuit signal to generate a turn off signal for controlling the signal generating circuit to latch the switching signal. | 05-03-2012 |
| 20120081039 | METHOD AND APPARATUS FOR A LED DRIVER WITH HIGH POWER FACTOR - A control circuit of a LED driver according to the present invention comprises an output circuit, an input circuit and an input-voltage detection circuit. The output circuit generates a switching signal to produce an output current for driving at least one LED in response to a feedback signal. The switching signal is coupled to switch a transformer. The input circuit samples an input signal for generating the feedback signal. The input signal is correlated to the output current of the LED driver. The input-voltage detection circuit generates an input-voltage signal in response to an input voltage of the LED driver. 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 LED driver. | 04-05-2012 |
| 20120057375 | METHOD 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 |
| 20120008352 | METHOD AND APPARATUS OF PROVIDING A BIASED CURRENT LIMIT FOR LIMITING MAXIMUM OUTPUT POWER OF POWER CONVERTERS - A biased current-limit circuit for limiting a maximum output power of a power converter includes an oscillator for generating a pulse signal and an oscillation signal. A waveform generator generates a waveform signal in response to the oscillation signal. A sample-hold circuit is used to sample the waveform signal to generate a hold signal in response to a switching signal. The sample-hold circuit further samples the hold signal to generate a current-limit threshold in response to a second-sampling signal. A current comparator is utilized to compare a current-sensing signal with the current-limit threshold to limit a maximum on-time of the switching signal. | 01-12-2012 |
| 20120001600 | CONTROL CIRCUIT OF INTERLEAVED PFC POWER CONVERTER - A control circuit of an interleaved PFC power converter according to the present invention comprises a master switching control circuit, a slave switching control circuit, and a slave reference signal generator. The master switching control circuit generates a control signal and a first switching signal in response to an input voltage and a feedback signal. The first switching signal is utilized to control a first switch of the PFC power converter. The slave reference signal generator generates a slave control signal in response to a load condition of the PFC power converter and the control signal. The slave switching control circuit generates a second switching signal in response to the slave control signal. The slave control signal is utilized to control a second switch of the PFC power converter. The slave reference signal generator adjusts the control signal in response to the load condition for generating the slave control signal correspondingly. The slave control signal drives the slave switching control circuit to adjust the switching frequency of the second switch for reducing the switching loss. | 01-05-2012 |
| 20110317454 | DUAL SWITCHES FLYBACK POWER CONVERTER WITH WIDE INPUT VOLTAGE RANGE - A dual switches Flyback power converter with a wide input voltage range according to the present invention comprises an input diode and an energy-store capacitor. The input diode can prevent the reflected voltage from the power transformer of the power converter to charge the electrolytic capacitor of the power converter. The energy-store capacitor will store the reflected voltage and the energy of the leakage inductor of the power transformer. The energy stored in the energy-store capacitor will be recycled to the output voltage of the power converter. Further, the input diode can be replaced by an input transistor to prevent the reflected voltage from the power transformer to charge the electrolytic capacitor. | 12-29-2011 |
| 20110317322 | CONTROL CIRCUIT WITH PROTECTION CIRCUIT FOR POWER SUPPLY - A control circuit with protection circuit for power supply according to the present invention comprises a peak-detection circuit and a protection circuit. The peak-detection circuit detects an AC input voltage and generates a peak-detection signal. The protection circuit comprises an over-voltage protection circuit. The over-voltage protection circuit generates an over-voltage protection signal in response to the peak-detection signal. The protection circuit generates a reset signal to reduce the output of the power supply in response to the over-voltage protection signal. The present invention can protect the power supply in response to the AC input voltage effectively through the peak-detection circuit. | 12-29-2011 |
| 20110305055 | ADAPTIVE SYNCHRONOUS RECTIFICATION CONTROL METHOD AND APPARATUS - An adaptive synchronous rectification control circuit and a control method are developed. The control circuit comprises an adaptive circuit that generates a reference signal in response to a detection signal of a power converter. A clamped circuit clamps the reference signal at a threshold voltage if the reference signal equals or is greater than the threshold voltage. A switching circuit generates a control signal to control a synchronous switch of the power converter in response to the detection signal and the reference signal. The control method generates the reference signal in response to the detection signal. The reference signal is clamped at the threshold voltage if the reference signal equals or is greater than the threshold voltage. The method further generates the control signal to control the synchronous switch of the power converter in response to the detection signal and the reference signal. | 12-15-2011 |
| 20110305051 | START-UP CIRCUIT WITH LOW STANDBY POWER LOSS FOR POWER CONVERTERS - A start-up circuit with low standby power loss for power converters according to present invention comprises a first diode and a second diode coupled to an input voltage of the power converter. A start-up resistor is coupled to the join of the first diode and the second diode. A high-voltage switch is coupled to the start-up resistor to generate a power source. A control circuit generates a switching signal for switching a transformer. A detection circuit generates a disable signal in response to the input voltage to disable the switching signal. A winding of the transformer is coupled to the power source to generate the power for the power source. The high-voltage switch is turned off to cut off the start-up resistor for saving the power loss once the voltage of the power source is higher than a threshold. | 12-15-2011 |
| 20110305048 | ACTIVE-CLAMP CIRCUIT FOR QUASI-RESONANT FLYBACK POWER CONVERTER - An active clamp circuit for a QR flyback power converter according to the present invention comprises an active-clamper connected to a primary winding of a power transformer of the QR flyback power converter in parallel. A high-side transistor driver is coupled to drive the active-damper. A charge-pump circuit is coupled to the high-side transistor driver to provide a power supply to the high-side transistor driver in accordance with a voltage source. A control circuit generates a control signal coupled to control the high-side transistor driver. The control signal is generated in response to a PWM signal and an input voltage of the QR flyback power converter. | 12-15-2011 |
| 20110260291 | Semiconductor Structure - A semiconductor structure. The semiconductor comprises a substrate, a first deep well, a diode and a transistor. The first deep well is formed in the substrate. The diode is formed in the first deep well. The transistor is formed in the first deep well. The diode is connected to a first voltage, the transistor is connected to a second voltage, and the diode and the transistor are cascaded. | 10-27-2011 |
| 20110254537 | Method and Apparatus for Detecting CCM Operation of a Magnetic Device - A method and an apparatus for detecting a CCM operation of a magnetic device are developed. The method generates a current signal in accordance with a switching current of the magnetic device and generates a first current signal and a second current signal by sampling the current signal. A mode signal is further generated according to the first current signal and the second current signal. The mode signal indicates the magnetic device is operated in CCM or DCM. The apparatus comprises a first sample circuit, a second sample circuit, and an arbiter. The first sample circuit samples the current signal to generate the first current signal. The second sample circuit samples the current signal to generate the second current signal. The arbiter generates the mode signal according to the first current signal and the second current signal for indicating the magnetic device is operated in CCM or DCM. | 10-20-2011 |
| 20110211281 | POWER SUPPLY WITH OPEN-LOOP PROTECTION - A power supply with an open-loop protection according to the present invention comprises a transformer, a switch, a signal generation circuit, a feedback detection circuit, a brown-out detection circuit, and a delay circuit. The transformer receives an input voltage. The switch is coupled to the transformer for switching the transformer. The signal generation circuit generates a switching signal to control the switch. The feedback detection circuit generates a pull-high signal in response to a feedback signal of the power supply. The brown-out detection circuit generates a delay signal in response to the pull-high signal and the input voltage. The delay circuit counts a delay time in response to the delay signal for generating a disabling signal coupled to the signal generation circuit to latch the switching signal. The brown-out detection circuit is utilized to detect whether the input voltage is in the brown-out condition for determining whether the open-loop protection is executed. | 09-01-2011 |
| 20110182090 | SWITCHING CONTROLLER FOR POWER CONVERTERS - A switching controller for power converter comprises a current-sense circuit and a PWM circuit, The current-sense circuit receives high-voltage signal across a first switch to generate a current-sense signal. The PWM circuit generates a switching signal to control the first switch in response to the current-sense signal. The switching controller further comprises a delay circuit. The delay circuit receives the switching signal to generate a delayed switching signal. The current-sense signal and the high-voltage signal ramp up with the same slope during the delayed switching signal is enabled. The current-sense signal will be pulled down to a level of a ground reference during the delayed switching signal is disabled. A delay time provided by the delay circuit avoids the high-voltage signal at the instance which the first switch is being turned off being conducted to a first comparator and a second comparator via a second switch. | 07-28-2011 |
| 20110180878 | High Side Semiconductor Structure - A high side semiconductor structure is provided. The high side semiconductor structure includes a substrate, a first deep well, a second deep well, a first active element, a second active element and a doped well. The first deep well and the second deep well are formed in the substrate, wherein the first deep well and the second deep well have identical type of ion doping. The first active element and the second active element are respectively formed in the first deep well and the second deep well. The doped well is formed in the substrate and is disposed between the first deep well and the second deep well. The doped well, the first deep well and the second deep well are interspaced, and the type of ion doping of the first deep well and the second deep well is complementary with that of the doped well. | 07-28-2011 |
| 20110180858 | Semiconductor Device - A semiconductor device. The semiconductor comprises a substrate, a VDMOS, a JFET, a first electrode, a second electrode, a third electrode and a fourth electrode. The VDMOS is formed in the substrate. The JFET is formed in the substrate. Wherein the first electrode, the second electrode and a third electrode are connected to the VDMOS and used as a first gate electrode, a first drain electrode and a first source electrode of the VDMOS respectively. The second electrode, the third electrode and the fourth electrode are connected to the JFET and used as a second drain electrode, a second gate electrode and a second drain electrode of the JFET respectively. | 07-28-2011 |
| 20110176341 | START-UP CIRCUIT TO DISCHARGE EMI FILTER OF POWER SUPPLIES - A start-up circuit to discharge EMI filter is developed for power saving. It includes a detection circuit detecting a power source for generating a sample signal. A sample circuit is coupled to the detection circuit for generating a reset signal in response to the sample signal. The reset signal is utilized for discharging a stored voltage of the EMI filter. | 07-21-2011 |
| 20110169418 | LED DRIVE CIRCUIT WITH A PROGRAMMABLE INPUT FOR LED LIGHTING - A LED drive circuit according to the present invention comprises a controller and a programmable signal. The controller generates a switching signal coupled to switch a magnetic device for generating an output current to drive a plurality of LEDs. The programmable signal is coupled to regulate a current-control signal of the controller. The switching signal is modulated in response to the current-control signal for regulating the output current, and the level of the output current is correlated to the current-control signal. | 07-14-2011 |
| 20110133829 | FEEDBACK CIRCUIT WITH FEEDBACK IMPEDANCE MODULATION FOR IMPROVING POWER SAVING - A feedback circuit with feedback impedance modulation according to the present invention comprises a compare circuit, a counter and a switching resistor circuit. The compare circuit receives a feedback signal of a power converter to compare the feedback signal with a threshold signal for generating a control signal. The feedback signal is correlated to a load condition of the power converter. The counter is coupled to the compare circuit and generates a modulation signal in response to the control signal. The switching resistor circuit is coupled to the counter and a feedback loop of the power converter for modulating a feedback impedance of the power converter in response to the modulation signal. The feedback impedance is directly modulated from a lower resistance to a higher resistance when the load condition is reduced from a half/full-load to a no/light-load. The feedback impedance is gradually modulated from a higher resistance to a lower resistance when the load condition is increased from the no/light-load to the half/full-load. | 06-09-2011 |
| 20110116287 | SWITCHING CONTROLLER HAVING SWITCHING FREQUENCY HOPPING FOR POWER CONVERTER - A switching controller having switching frequency hopping for a power converter includes an oscillator generating a pulse signal for determining a switching frequency of a switching signal, a maximum duty-cycle circuit generating a maximum duty-cycle signal in response to the switching signal for determining the switching frequency of the switching signal, a pattern generator generating a digital pattern code in response to a clock signal, a programmable capacitor coupled to the pattern generator and the oscillator for modulating the switching frequency of the switching signal in response to the digital pattern code, and a PWM circuit coupled to the oscillator and the maximum duty-cycle circuit for generating the switching signal in accordance with the pulse signal and the maximum duty-cycle signal. A maximum on-time of the switching signal is limited by the maximum duty-cycle signal. The switching signal is utilized to switch a transformer of the power converter. | 05-19-2011 |
| 20110038180 | RESONANT POWER CONVERTER WITH HALF BRIDGE AND FULL BRIDGE OPERATIONS AND METHOD FOR CONTROL THEREOF - A resonant power converter with half bridge and full bridge operations and a method for control thereof are provided. The resonant power converter includes a full bridge circuit, a control circuit and a PFC circuit. The full bridge circuit switches a power transformer in response to switching signals. The control circuit coupled to receive a feedback signal and an input signal generates switching signals. The feedback signal is correlated to the output of the power converter and the input signal is correlated to the input voltage of the full bridge circuit, where the full bridge circuit is operated as a full bridge switching when the input signal is lower than a threshold, and the full bridge circuit is operated as a half bridge switching when the input signal is higher than the threshold. The PFC circuit generates the input voltage of the full bridge circuit. | 02-17-2011 |
| 20100253307 | PFC CONVERTER HAVING TWO-LEVEL OUTPUT VOLTAGE WITHOUT VOLTAGE UNDERSHOOTING - A switching controller for a PFC converter is provided. The switching controller comprises a switching-control circuit, a current-command circuit, a programmable feedback circuit, a modulator, an over-voltage detection circuit, and a light-load detection circuit. The switching controller is capable of regulating a bulk voltage of the PFC converter at different levels in response to load conditions of the PFC converter. A turbo current eliminates a first voltage undershooting of the bulk voltage at the transient that the bulk voltage decreases to arrive at a second level from a first level. A voltage-loop error signal is maximized to eliminate a second voltage undershooting of the bulk voltage at the transient that the bulk voltage starts to increase toward the first level from the second level. | 10-07-2010 |
| 20100232187 | OUTPUT VOLTAGE CONTROL CIRCUIT OF POWER CONVERTER FOR LIGHT-LOAD POWER SAVING - A control circuit of a power converter for light-load power saving according to the present invention comprises a first feedback circuit coupled to an output voltage of the power converter to receive a first feedback signal. A second feedback circuit is coupled to the output voltage to receive a second feedback signal. A control circuit generates a switching signal for switching a transformer of the power converter and regulating the output voltage of the power converter in response to the first feedback signal and the second feedback signal. The switching signal is generated in accordance with the first feedback signal when an output load is high. The switching signal is generated in accordance with the second feedback signal during a light-load condition. | 09-16-2010 |
| 20100232183 | CONTROL CIRCUIT OF RESONANT POWER CONVERTER WITH ASYMMETRICAL PHASE SHIFT TO IMPROVE THE OPERATION - A control circuit of the resonant power converter according to the present invention comprises a frequency modulation circuit modulating a switching frequency of a switching signal in response to a feedback signal in a first operation range. A phase-shift circuit performs a phase-shift modulation to the switching signal in response to the feedback signal in a second operation range. A burst circuit performs a burst modulation to the switching signal in response to the feedback signal in a third operation range. The control circuit is operated in the first operation range when the feedback signal is higher than a first threshold. The control circuit is operated in the second operation range when the feedback signal is lower than the first threshold and higher than a second threshold. The control circuit is operated in the third operation range when the feedback signal is lower than the second threshold. | 09-16-2010 |
| 20100202167 | SOFT SWITCHING POWER CONVERTER WITH A VARIABLE SWITCHING FREQUENCY FOR IMPROVING OPERATION AND EFFICIENCY - A power converter according to the present invention comprises a resonant tank. The resonant tank is switched by a plurality of transistors. A control circuit generates a plurality of switching signals to control the transistors. The pulse widths of the switching signals are modulated for regulating an output voltage of the power converter. The control circuit is coupled to detect an input voltage of the power converter. The frequency of the switching signals is changed in response to the change of the input voltage or/and an output load of the power converter. | 08-12-2010 |
| 20100124079 | OFFLINE SYNCHRONOUS RECTIFIER WITH CAUSAL CIRCUIT FOR RESONANT SWITCHING POWER CONVERTER - A synchronous rectifier of a resonant switching power converter is provided to improve efficiency. The synchronous rectifier includes a power transistor and a diode connected to a transformer and an output of the resonant switching power converter for ratifications. A controller generates a drive signal to control the power transistor in response to an on signal and an off signal. A causal circuit is developed to generate the off signal in accordance with the on signal. The on signal is enabled once the diode is forward biased. The on signal is coupled to enable the drive signal for switching on the power transistor. The off signal is coupled to disable the drive signal for switching off the power transistor. The off signal is enabled before the on signal is disabled. | 05-20-2010 |
| 20100123449 | WALL CONTROL INTERFACE WITH PHASE MODULATION AND DETECTION FOR POWER MANAGEMENT - A wall control interface for power management includes a transmitting circuit that generates a switching signal to control a switch and achieve a phase modulation to a power line signal in response to a transmitting-data. A receiving circuit is coupled to detect the phase of the power line signal for generating a data signal and a receiving-data in response to the phase of the power line signal. The receiving circuit further generates a control signal to control power of a load in accordance with the data signal or the receiving-data. The phase modulation is achieved by controlling a turn-on angle of the power line signal. The switch remains in a turn-on state during the normal condition, which achieves good power and low current harmonic. The phase modulation is only performed during the communication of the power management. | 05-20-2010 |
| 20100097104 | CONTROL CIRCUIT HAVING OFF-TIME MODULATION TO OPERATE POWER CONVERTER AT QUASI-RESONANCE AND IN CONTINUOUS CURRENT MODE - A control circuit is developed to adaptively operate a power converter at quasi-resonance (QR) and in a continuous current mode (CCM) to achieve high efficiency. The control circuit includes a PWM circuit generating a switching signal coupled to switch a transformer. A signal generation circuit generates a ramp signal and a pulse signal. The pulse signal is generated in response to the ramp signal for switching on the switching signal. A feedback circuit produces a feedback signal according to an output load of the power converter. The feedback signal is coupled to switch off the switching signal. A detection circuit is coupled to the transformer for generating a valley signal in response to the waveform of the transformer. The valley signal is further coupled to generate the pulse signal when the ramp signal is lower than a threshold. The level of the threshold is correlated to the feedback signal. | 04-22-2010 |
| 20100039088 | INTERLEAVED SLAVE SWITCHING CIRCUIT FOR DISCONTINUOUS MODE PFC CONVERTER - A slave switching circuit for a master-slave PFC converter is disclosed. The slave switching circuit includes a phase-detection circuit coupled to detect a master-switching signal and a slave-inductor signal for generating a start signal and a phase-lock signal. The start signal is coupled to enable a slave-switching signal. The slave-switching signal is coupled to switch a slave inductor. An on-time-adjust circuit is used to adjust the on-time of the slave-switching signal in accordance with the phase-lock signal. The slave-inductor signal is correlated to the demagnetization of the slave inductor. The phase-lock signal is coupled to minimize the period between the disablement of the slave-inductor signal and the enablement of the start signal. | 02-18-2010 |
| 20100038677 | Semiconductor device for electrostatic discharge protection - A semiconductor device for electrostatic discharge protection is disclosed, and at least comprises a high-voltage parasite silicon controlled rectifier (HVSCR) and a diode. The HVSCR has an anode and a cathode, and the cathode of HVSCR is coupled to a ground. The diode, coupled to the HVSCR in series, also has an anode and a cathode. The anode of the diode is coupled to the anode of the HVSCR, and the cathode of the diode is coupled to a terminal applied with a positive voltage. The diode has a second conductivity type zone that could be constructed to form several strips or small blocks spaced apart from each other. Those small blocks could be any shapes and arranged regularly or randomly. | 02-18-2010 |
| 20100033991 | SWITCHING CONTROLLER HAVING SWITCHING FREQUENCY HOPPING FOR POWER CONVERTER - A switching controller having switching frequency hopping for a power converter includes a first oscillator generating a pulse signal and a maximum duty-cycle signal for determining a switching frequency of a switching signal, a pattern generator having a second oscillator and generating a digital pattern code in response to a clock signal, a programmable capacitor coupled to the pattern generator and the first oscillator for modulating the switching frequency of the switching signal in response to the digital pattern code, and a PWM circuit coupled to the first oscillator for generating the switching signal in accordance with the maximum duty-cycle signal. A maximum on-time of the switching signal is limited by the maximum duty-cycle signal. The switching signal is utilized to switch a transformer of the power converter. | 02-11-2010 |
| 20100014324 | OFFLINE SYNCHRONOUS RECTIFYING CIRCUIT WITH SENSE TRANSISTOR FOR RESONANT SWITCHING POWER CONVERTER - A synchronous rectifying circuit of a resonant switching power converter is provided to improve the efficiency. The synchronous rectifying circuit includes a power transistor and a diode connected to a transformer and an output ground of the power converter for rectifying. A sense transistor is coupled to the power transistor for generating a mirror current correlated to a current of the power transistor. A controller generates a driving signal to control the power transistor in response to a switching-current signal. A current-sense device is coupled to the sense transistor for generating the switching-current signal in response to the mirror current. The controller enables the driving signal to turn on the power transistor once the diode is forwardly biased. The controller generates a reset signal to disable the driving signal and turn off the power transistor once the switching-current signal is lower than a threshold. | 01-21-2010 |
| 20100007394 | METHOD AND APPARATUS OF PROVIDING A BIASED CURRENT LIMIT FOR LIMITING MAXIMUM OUTPUT POWER OF POWER CONVERTERS - A biased current-limit circuit for limiting a maximum output power of a power converter includes an oscillator for generating a pulse signal. A waveform generator generates a waveform signal in response to a switching signal and a second-sampling signal. A sample-hold circuit is used to sample the waveform signal to generate a hold signal in response to a first-sampling signal. The sample-hold circuit further samples the hold signal to generate a current-limit threshold in response to the second-sampling signal. A current comparator is utilized to compare a current-sensing signal with the current-limit threshold to limit a maximum on-time of the switching signal. | 01-14-2010 |
| 20090316451 | APPARATUS PROVIDING PROTECTION FOR POWER CONVERTER - A switching circuit for a power converter includes an oscillation circuit, a first circuit, and a first comparator. The oscillation circuit generates a switching signal for regulating an output of the power converter. The first circuit generates a threshold signal. The first comparator is coupled to receive a signal representative of a current through a power switch. Besides, the first comparator generates a control signal in response to the signal and the threshold signal. A frequency of the switching signal is increased in response to the enabling of the control signal. | 12-24-2009 |
| 20090219003 | OFFLINE SYNCHRONOUS SWITCHING REGULATOR - An offline synchronous switching regulator is proposed for improving the efficiency thereof. Switches are coupled to switch a transformer and generate a switching signal at a secondary side of the transformer. A switching circuit is coupled to an output of the regulator to generate pulse signals in response to the switching signal and a feedback signal. Pulse signals are utilized to control a synchronous switch for rectifying and regulating the regulator. The synchronous switch includes a power-switch set and a control circuit. The control circuit receives pulse signals for turning on/off the power-switch set. The power-switch set is connected in between the transformer and the output of the regulator. A flyback switch freewheels an inductor current and can be turned on in response to the off state of the power-switch set whose on-time is correlated to the on-time of the power-switch set. | 09-03-2009 |
| 20090200997 | SWITCHING CONTROLLER HAVING PROGRAMMABLE FEEDBACK CIRCUIT FOR POWER CONVERTERS - A switching controller for a boost power converter includes a switching-control circuit and a programmable feedback circuit. The programmable feedback circuit is coupled to an output of the boost power converter via a voltage divider. The programmable feedback circuit includes a current source coupled to a switch. On a light-load condition, a power-saving signal turns on the switch. The switch will conduct a programming current supplied by the current source toward the voltage divider. Furthermore, the voltage divider is externally adjustable for programming a determined level of an output voltage of the boost power converter on the light-load condition. Additionally the present invention increases system design flexibility to meet practical power-saving requirements without adding circuitries and increasing cost. | 08-13-2009 |
| 20090129125 | SYNCHRONOUS REGULATION CIRCUIT - A primary-side switching circuit generates switching signals for switching a transformer. A secondary-side switching circuit is coupled to an output of the power converter to generate pulse signals in response to the switching signals and an output voltage of the power converter. Pulse signals are generated to rectify and regulate the power converter. A synchronous switch includes a power-switch set and a control circuit. The control circuit receives the pulse signals via capacitors for turning on/off the power-switch set. The power-switch set is connected in between the transformer and the output of the power converter. Furthermore, a flyback switch is operated to freewheel the inductor current of the power converter. The flyback switch is turned on in response to the off state of the power-switch set. The on time of the flyback switch is programmable and correlated to the on time of the power-switch set. | 05-21-2009 |
| 20090110129 | SYNCHRONOUS RECTIFYING CIRCUIT FOR OFFLINE POWER CONVERTER - A synchronous rectifying circuit is provided for power converter. An integrated synchronous rectifier has a rectifying terminal, a ground terminal a first input terminal and a second input terminal. The rectifying terminal is coupled to secondary side of a transformer. The ground terminal coupled to output of the power converter. A power transistor is connected between the rectifying terminal and the ground terminal. The first input terminal and the second input terminal are coupled to receive a pulse signal for turning on/off the power transistor. A pulse-signal generation circuit includes an input terminal coupled to receive the switching signal for switching the transformer of the power converter. A first output terminal and a second output terminal of the pulse-signal generation circuit generate the pulse signal. An isolation device is coupled between the first input terminal and the second input terminal, and the first output terminal and the second output terminal. | 04-30-2009 |
| 20090091951 | CONTROL CIRCUIT FOR SYNCHRONOUS RECTIFYING AND SOFT SWITCHING OF POWER CONVERTERS - A control circuit for soft switching and synchronous rectifying is provided for power converter. A switching-signal circuit is used for generating drive signals and a pulse signal in response to a leading edge and a trailing edge of a switching signal. The switching signal is developed for regulating the power converter. Drive signals are coupled to switch the power transformer. A propagation delay is developed between drive signals to achieve soft switching of the power converter. An isolation device is coupled to transfer the pulse signal from a primary side of a power transformer to a secondary side of the power transformer. A controller of the integrated synchronous rectifier is coupled to the secondary side of the power transformer for the rectifying operation. The controller is operated to receive the pulse signal for switching on/off the power transistor. The pulse signal is to set or reset a latch circuit of the controller for controlling the power transistor. | 04-09-2009 |
| 20090058389 | CONTROL CIRCUIT FOR MEASURING AND REGULATING OUTPUT CURRENT OF CCM POWER CONVERTER - A switching control circuit is provided for measuring and regulating an output current of a power converter. The power converter is operated under continuous current mode. A detection circuit generates a continuous-current signal and a peak-current signal by detecting a switching current of an inductive device. An integration circuit generates an average-current signal in response to the continuous-current signal, the peak-current signal and an off time of a switching signal. The switching control circuit generates the switching signal in response to the average-current signal. The switching signal is coupled to switch the inductive device and regulate the output current of the power converter. A time constant of the integration circuit is correlated to the switching period of the switching signal, therefore the average-current signal will be proportional to the output current. | 03-05-2009 |
| 20090040792 | SYNCHRONOUS RECTIFYING CIRCUIT FOR RESONANT POWER CONVERTERS - A synchronous rectifying circuit is provided for resonant power converter. An integrated synchronous rectifier comprises a rectifying terminal, a ground terminal a first input terminal and a second input terminal. The rectifying terminal is coupled to the secondary side of a power transformer. The ground terminal is coupled to the output of the power converter. A power transistor is connected between the rectifying terminal and the ground terminal. The first input terminal and the second input terminal are coupled to receive a pulse signal for turning on/off the power transistor. A pulse-signal generation circuit includes an input circuit coupled to receive the switching signal for switching the power transformer of the power converter. | 02-12-2009 |
| 20090033244 | INTEGRATED CIRCUIT WITH A PREHEAT CONTROL FOR A BALLAST - The present invention provides a ballast with preheat function for fluorescent or compact fluorescent lamps. The lamp is connected in series with an inductor and a capacitor to form a resonant circuit. A first switch and a second switch controlled by control circuit are coupled to the resonant circuit for switching the resonant circuit. A RC circuit is composed of a first resistor and a second resistor connected in series to form a voltage divider, and a capacitor is connected in parallel with second resistor. Switching frequency is voltage dependent. | 02-05-2009 |
| 20090027926 | METHOD AND APPARATUS TO PROVIDE SYNCHRONOUS RECTIFYING CIRCUIT FOR FLYBACK POWER CONVERTERS - A synchronous rectifying circuit is provided for flyback power converter. A pulse generator is utilized to generate a pulse signal in response to a leading edge and a trailing edge of a switching signal. The switching signal is used for switching the transformer of the power converter. An isolation device such as pulse transformer or small capacitors is coupled to the pulse generator for transferring the pulse signal through an isolation barrier of a transformer. A synchronous rectifier includes a power switch and a control circuit. The power switch is connected in between the secondary side of the transformer and the output of the power converter for the rectifying operation. The control circuit having a latch is operated to receive the pulse signal for controlling the power switch. | 01-29-2009 |
| 20090003019 | SYNCHRONOUS RECTIFICATION CIRCUIT FOR POWER CONVERTERS - A synchronous rectification circuit for power converters operable under fixed and/or variable frequencies where no current sense circuit or phase-lock circuit are needed is provided. It has a power switch coupled to a transformer for the rectification. A signal-generation circuit is used for generating a control signal in response to a magnetized voltage of the transformer, a demagnetized voltage of the transformer, and a magnetization period of the transformer. The control signal is coupled to turn on the power switch. The enable period of the control signal is correlated to a demagnetization period of the transformer. | 01-01-2009 |
| 20080310203 | METHOD AND APPARATUS TO PROVIDE SYNCHRONOUS RECTIFYING CIRCUIT FOR OFFLINE POWER CONVERTERS - A synchronous rectifying circuit is provided for power converter. A pulse signal generator is utilized to generate a pulse signal in response to the leading edge and the trailing edge of a switching signal. The switching signal is used for switching the transformer of the power converter. An isolation device such as pulse transformer or small capacitors is coupled to the pulse signal generator for transferring the pulse signal through an isolation barrier of a transformer. A synchronous rectifier includes a power switch and a control circuit. The power switch is equipped in between the secondary side of the transformer and the output of the power converter for the rectifying. The control circuit having a latch is operated to receive the pulse signal for turning on/off the power switch. | 12-18-2008 |
| 20080309380 | METHOD AND APPARATUS FOR DETECTING SWITCHING CURRENT OF MAGNETIC DEVICE OPERATED IN CONTINUOUS CURRENT MODE - The present invention provides a method and apparatus for detecting a continuous current of a switching current. A current signal is produced in response to a switching current of the magnetic device. By sampling the waveform of the current signal in response to the enabling of a switching signal, a first current signal and a second current signal are generated. A continuous current signal is produced according to the first current signal and the second current signal. The continuous current signal is corrected to the continuous current of the switching current. | 12-18-2008 |
| 20080309256 | INTEGRATED CIRCUIT CONTROLLER FOR BALLAST - The present invention provides an integrated circuit controller for ballast with preheat/repreheat filament and ignition time control. A charge/discharge circuit is connected to a capacitor to provide the charge/discharge path for the capacitor. It charges when integrated circuit controller without errors and discharges when error occurred during lamp operation or power tripped. A control circuit is coupled to the charge/discharge circuit to control the charge/discharge circuit to charge or discharge the capacitor. A compare circuit is coupled to the charge/discharge circuit to compare a voltage signal on the capacitor from the charge/discharge circuit with threshold voltages for timing control and providing a preheat signal and an ignition signal. A control logic circuit is coupled to the control circuit to control the control circuit and coupled to the compare circuit to receive the preheat signal and the ignition signal for preheating the filament and igniting the lamp. The control logic circuit further receives a feedback voltage for over voltage protect. Once the feedback voltage is over its threshold voltage in the control logic circuit, the control logic circuit controls the control circuit for discharging the capacitor. | 12-18-2008 |
| 20080278279 | Semiconductor structure with high breakdown voltage and resistance and method for manufacturing the same - A semiconductor structure with high breakdown voltage and high resistance and method for manufacturing the same. The semiconductor structure at least comprises a substrate having a first conductive type; a deep well having a second conductive type formed in the substrate; two first wells having the first conductive type and formed within the deep well; a second well having the first conductive type and formed between two first wells within the deep well, and a implant dosage of the second well lighter than a implant dosage of the first well; and two first doping regions having the first conductive type and respectively formed within the first wells. | 11-13-2008 |
| 20080277728 | Semiconductor structure for protecting an internal integrated circuit and method for manufacturing the same - A semiconductor structure for protecting an internal integrated circuit comprises a substrate; a plurality of first doping regions formed in the substrate and disposed substantially within an N-well; a plurality of second doping regions, formed in the substrate and disposed within an P-well; a N+ section, formed in the substrate and enclosing the N-well and the P-well; a pad, formed above the substrate and electrically connected to at least one of the first doping regions; and a first ground and a second ground respectively disposed to positions corresponding to outside and inside of the N+ section. Also, the second doping regions are isolated from the first doping regions. The first and second doping regions located within the N+ section are isolated from the substrate by the N+ section. Furthermore, the second ground is electrically connected to at least one of the second doping regions. | 11-13-2008 |
| 20080248638 | PROCESS FOR MANUFACTURING VOLTAGE-CONTROLLED TRANSISTOR - The present invention provides a self-driven LDMOS which utilizes a parasitic resistor between a drain terminal and an auxiliary region. The parasitic resistor is formed between two depletion boundaries in a quasi-linked deep N-type well. When the two depletion boundaries pinch off, a gate-voltage potential at a gate terminal is clipped at a drain-voltage potential at said drain terminal. Since the gate-voltage potential is designed to be equal to or higher than a start-threshold voltage, the LDMOS is turned on accordingly. Besides, no additional die space and masking process are needed to manufacture the parasitic resistor. Furthermore, the parasitic resistor of the present invention does not lower the breakdown voltage and the operating speed of the LDMOS. In addition, when the two depletion boundaries pinch off, the gate-voltage potential does not vary in response to an increment of the drain-voltage potential. | 10-09-2008 |
| 20080232147 | RESONANT INVERTER - The present invention provides a low-cost resonant inverter circuit for ballast. The resonant circuit includes a transformer connected in series with a lamp to operate the lamp. A first transistor and a second transistor are coupled to switch the resonant inverter circuit. A second winding and a third winding of the transformer are used for generating control signals in response to a switching current of the resonant inverter circuit. The transistor is turned on once the control signal is higher than a high-threshold. Next, the transistor is turned off once the control signal is lower than a low-threshold. Therefore, soft switching operation for the first transistor and the second transistor is achieved. | 09-25-2008 |
| 20080232142 | OUTPUT CURRENT CONTROL CIRCUIT FOR POWER CONVERTER WITH A CHANGEABLE SWITCHING FREQUENCY - A control circuit controls the output current of the power converter at the primary side of the transformer. The control circuit includes a current-detection circuit for generating a primary-current signal in response to the switching current of the transformer. A voltage-detection circuit is coupled to the transformer to generate a period signal and a discharge-time signal in response to the reflected voltage of the transformer. A signal-process circuit is utilized to generate a current signal in response to the primary-current signal, the period signal and the discharge-time signal. The period signal is correlated to the switching period of the switching signal of the power converter. The discharge-time signal is correlated to the duty cycle of switching current at the secondary-side of the transformer. The current signal is correlated to the output current of the power converter. | 09-25-2008 |
| 20080231205 | CURRENT MODE RESONANT INVERTER - The present invention provides a low-cost inverter for ballast. A current transformer is connected in series with a lamp to operate the lamp. A first transistor and a second transistor are coupled to switch the resonant circuit. The current transformer is utilized to generating control signals in response to the switching current of the resonant circuit. The transistor is turned on once the control signal is higher than a first threshold. After that, the transistor is turned off once the control signal is lower than a second threshold. Therefore, a soft switching operation for the first transistor and the second transistor can be achieved. | 09-25-2008 |
| 20080225560 | SWITCHING CONTROLLER FOR PARALLEL POWER CONVERTERS - A switching controller for parallel power converters is disclosed. The switching controller includes an input circuit coupled to an input terminal of the switching controller to receive an input signal. An integration circuit is coupled to the input circuit to generate an integration signal in response to the pulse width of the input signal. A control circuit generates a switching signal for switching the power converters. The switching signal is enabled in response to the enabling of the input signal. A programmable delay time is generated between the input signal and the switching signal. The pulse width of the switching signal is determined in response to the integration signal. | 09-18-2008 |
