LEADTREND TECHNOLOGY CORP. Patent applications |
Patent application number | Title | Published |
20140233268 | CONTROLLER OF A POWER CONVERTER WITH ADJUSTABLE JITTER AMPLITUDE AND METHOD OF GENERATING ADJUSTABLE JITTER AMPLITUDE THEREOF - A controller of a power converter with adjustable jitter amplitude includes a feedback pin, a logic circuit, an auxiliary pin, and a current sensing pin. The feedback pin is used for receiving a feedback voltage from a secondary side of the power converter. The feedback voltage corresponds to an output voltage of the secondary side of the power converter. The logic circuit is used for generating a jitter signal according to a clock, the feedback voltage, and a first resistor. The auxiliary pin is used for receiving a voltage corresponding to an auxiliary winding of the power converter. The current sensing pin is used for generating a detection voltage according to a current flowing through a primary side of the power converter. The voltage, the jitter signal, and the detection voltage determine turning-on time of the primary side of the power converter. | 08-21-2014 |
20140211511 | CONTROLLER FOR DETECTING AN OUTPUT CURRENT OF A POWER CONVERTER, DEVICE FOR DETECTING AN AVERAGE OUTPUT CURRENT OF A POWER CONVERTER, METHOD FOR DETECTING AN AVERAGE OUTPUT CURRENT OF A POWER CONVERTER, AND METHOD FOR DETECTING AN OUTPUT CURRENT OF A POWER CONVERTER - A device for detecting an average output current of a power converter includes a current generation unit, a first voltage generation unit, a first current mirror unit, and a second current mirror unit. The current generation unit generates a first charge current according to an intermediate voltage. The first voltage generation unit generates a first node voltage according to the first charge current, a first discharge current, a turning-on time, and an inverse turning-on time. The first current mirror unit generates a first current according to the first node voltage, and generates a second voltage corresponding to the average output current of a secondary side of the power converter according to the first current. The second current mirror unit generates the first discharge current according to the first current. | 07-31-2014 |
20140140108 | CONTROLLER FOR GENERATING JITTERS IN A CONSTANT CURRENT MODE OF A POWER CONVERTER AND METHOD THEREOF - A controller for generating jitters in a constant current mode of a power converter includes a current pin, an auxiliary pin, a constant current control unit, and a control signal generation unit. The current pin is used for receiving a primary side voltage determined according to a resistor and a primary side current flowing through the power converter. The auxiliary pin is used for receiving a voltage corresponding to an auxiliary winding of the power converter. The constant current control unit is used for generating an adjustment signal according to the primary side voltage, a discharge time corresponding to the voltage, and a reference voltage. The reference voltage has a predetermined range jitter voltage. The control signal generation unit is used for adjusting a period of a gate control signal according to the adjustment signal. | 05-22-2014 |
20140098570 | CONTROLLER FOR CONTROLLING A POWER CONVERTER TO OUTPUT CONSTANT POWER AND RELATED METHOD THEREOF - A controller for controlling a power converter to output constant power includes a current sensing module, a voltage generation module, and a voltage regulation module. The current sensing module generates a sensing current according to an output current flowing through a secondary side of the power converter. The voltage generation module generates a set voltage corresponding to a reciprocal of the sensing current according to the sensing current. The voltage regulation module generates a regulation voltage to a feedback circuit of the secondary side of the power converter according to the set voltage and a sensing voltage corresponding to an output voltage of the secondary side of the power converter. The feedback circuit and a primary side of the power converter regulate the output voltage according to the regulation voltage, where a product of the output voltage and the output current is a constant value. | 04-10-2014 |
20140043876 | ACTIVE FEEDBACK CONTROL INTEGRATED CIRCUIT APPLIED TO AN ALTERNATING CURRENT/DIRECT CURRENT CONVERTER AND OPERATION METHOD THEREOF - An active feedback control integrated circuit applied to an alternating current/direct current converter includes a feedback pin, an operation unit, a control unit, and a controlled-current generation unit. The feedback pin is used for receiving a feedback current of an output feedback unit of the alternating current/direct current converter. The operation unit is used for generating an operation signal according to the feedback current. The control unit is coupled to the operation unit for generating a current control signal. The controlled-current generation unit is coupled to the control unit for generating a controlled current to the feedback pin according to the current control signal. | 02-13-2014 |
20140043874 | CIRCUIT FOR CONTROLLING A LATCH MODE OF A PULSE WIDTH MODULATION CIRCUIT AND METHOD THEREOF - A circuit for controlling a latch mode of a pulse width modulation circuit includes a D flip-flop, a voltage generation unit, a comparator, and a logic unit. The D flip-flop generates a switch control signal according to a latch enable signal. The voltage generation unit generates a discharge current, and a voltage divider resistor group included in the voltage generation unit generates a first voltage when the voltage generation unit is turned on according to the switch control signal. A voltage of a predetermined pin of the pulse width modulation circuit is equal to a predetermined voltage when the discharge current is equal to the charge current. The comparator compares a reference voltage with the first voltage to generate a comparison signal. The logic unit generates a clear signal according to the comparison signal. The D flip-flop clears the switch control signal according to the clear signal. | 02-13-2014 |
20140043081 | SAMPLE-AND-HOLD CIRCUIT FOR GENERATING A VARIABLE SAMPLE DELAY TIME OF A TRANSFORMER AND METHOD THEREOF - A sample-and-hold circuit for generating a variable sample delay time of a transformer includes a discharge detection unit, a sample delay time generation unit, and a comparator. The discharge detection unit generates a first voltage according to a first turning-on signal and a first reference current. Length of the first turning-on signal is varied with a discharge time of a present period of the transformer. The sample delay time generation unit generates a second voltage according to the first turning-on signal and a second reference current. The comparator generates a sample signal to a control circuit of the transformer according to a first voltage corresponding to a previous period of the transformer and a second voltage corresponding to the present period of the transformer. The first reference current is K times the second reference current, and 002-13-2014 | |
20140042924 | CIRCUIT WITH ADJUSTABLE PHASE DELAY AND A FEEDBACK VOLTAGE AND METHOD FOR ADJUSTING PHASE DELAY AND A FEEDBACK VOLTAGE - A circuit with adjustable phase delay and a feedback voltage includes a delay setting unit and a phase delay signal generator. The delay setting unit generates a delay time according to an external resistor. The phase delay signal generator includes a plurality of phase delay units. Each phase delay unit includes an edge trigger subunit and a signal generation subunit. The edge trigger subunit receives an input signal, and generates a positive edge trigger signal and a negative edge trigger signal according to a positive edge and a negative edge of the input signal, respectively. The signal generation subunit generates and outputs a phase delay signal according to the positive edge trigger signal, the negative edge trigger signal, and the delay time. The phase delay signal lags the input signal for the delay time. | 02-13-2014 |
20140001978 | CALIBRATION APPARATUS AND METHOD THEREOF, MULTI-CHANNEL DRIVING CIRCUIT AND CURRENT BALANCING METHOD | 01-02-2014 |
20130307606 | SUPER HIGH VOLTAGE DEVICE AND METHOD FOR OPERATING A SUPER HIGH VOLTAGE DEVICE - A super high voltage device includes a first gate, a second gate, a drain, a first source, a second source, and a third source. The first gate is used for receiving a first control signal generated from a pulse width modulation controller. The second gate is used for receiving a second control signal generated from the pulse width modulation controller. The drain is used for receiving an input voltage. First current flowing from the drain to the first source varies with the first control signal and the input voltage. The second control signal is used for controlling turning-on and turning-off of second current flowing from the drain to the second source and third current flowing from the drain to the third source. The third source is proportional to the second current. | 11-21-2013 |
20130301303 | POWER CONTROLLERS AND CONTROL METHODS - Disclosed include power controllers and related control methods. A disclosed power controller has a pulse generator, a sample/hold device, a comparator, and a switch controller. The pulse generator provides an enable signal, defining an enable time. The comparator has two inputs capable of being coupled to a reference signal and a feedback signal, respectively, and an output coupled to a compensation capacitor. When enabled by the enable signal, the comparator charges/discharges the compensation capacitor. The switch controller controls a power switch according to a compensation voltage of the compensation capacitor. A feedback voltage of the feedback signal is able to correspond to an output voltage of the power supply. | 11-14-2013 |
20130301302 | POWER SUPPLY AND POWER CONTROLLER - Power supplies and power controllers are disclosed. A disclosed power supply has a power controller, a power switch, an auxiliary winding, a first circuit and a second circuit. The power controller is a monolithic integrated circuit with a multi-function pin and a gate pin. A control node of the power switch is coupled to the gate pin. The first circuit is coupled between the multi-function pin and the auxiliary winding and has a diode. The second circuit is coupled between the multi-function pin and a ground line, and has a thermistor. | 11-14-2013 |
20130250620 | CONTROL CIRCUIT FOR REDUCING TOUCH CURRENT OF A POWER CONVERTER AND OPERATION METHOD THEREOF - A control circuit for reducing touch current of a power converter includes an auxiliary pin, a zero-crossing signal generator, a feedback pin, a frequency limiting signal generator, and a gate signal generator. The auxiliary pin receives a voltage corresponding to an auxiliary winding of the power converter. The zero-crossing signal generator generates a zero-crossing signal according to the voltage and a first reference voltage. The feedback pin receives a feedback voltage corresponding to an output voltage of the power converter. The frequency limiting signal generator generates a frequency limiting signal according to the feedback voltage and a second reference voltage. The frequency limiting signal limits the gate control signal to a predetermined frequency. The gate signal generator generates a gate control signal to a power switch of the power converter according to the frequency limiting signal and the zero-crossing signal. | 09-26-2013 |
20130187621 | Power control circuits and methods - Power control circuits and methods are disclosed, suitable for a power supplier. A power control circuit has a clock generator, a phase controller and a power limiter. The clock generator provides a clock signal, substantially determining switching cycles of a power supply. The phase controller outputs a burst signal based on a group reference signal and a burst initiation signal, and makes a burst period corresponding to a burst signal not less than a group reference period corresponding to the group reference signal. The burst signal is capable of switching the power supplier between a switching state and a non-switching state. The power limiter limits the power transferred by the power supply in every switching cycle, during a burst-up duration after the power supply is switched from the non-switching state to the switching state. The burst initiation signal correlates to an output voltage of the power supplier. | 07-25-2013 |
20130147362 | SHORT CIRCUIT DETECTION CIRCUIT AND CONTROL METHOD THEREOF - A short circuit detection circuit for detecting short circuit of a series of light-emitting diodes includes a constant current source, a rectifier, and a detector. The constant circuit source provides a setting current. The rectifier is coupled between a feedback node and the constant current source. The feedback node is coupled to a terminal of the series of light-emitting diodes. When a feedback voltage of the feedback node exceeds a short reference voltage, the rectifier allows the setting current sinks the feedback node. The detector detects the feedback voltage of the feedback node. When the feedback voltage exceeds a predetermined value, short-circuit protection is triggered to make the series of light-emitting diodes be turned off. | 06-13-2013 |
20130135905 | CONTROL METHODS FOR SWITCHING POWER SUPPLIES - An embodiment provides a control method capable of controlling a switching-mode power supply to provide an output power source. The switching-mode power supply has a winding coupled to an input power source and controlled by a switch to be energized or de-energized. The maximum current peak through the winding is set to be a predetermined value. A discharge time of the winding in a switching cycle period is detected. The switching cycle period of the switch is controlled to keep the ratio of the discharge time to the switching cycle period as a constant. | 05-30-2013 |
20130134904 | DIMMING DRIVING SYSTEM AND DIMMING CONTROLLER - Disclosed are dimming driving system and a dimming controller. A disclosed dimming driving system has a transformer, a lighting device, and a dimming controller. The transformer has a primary winding and a secondary winding inductively-coupled to each other. The secondary winding is coupled to an output power line and secondary ground, both coupling to and powering the lighting device. The dimming controller is coupled to the secondary winding for controlling current flowing through the lighting device according to a voltage drop of the secondary winding. | 05-30-2013 |
20130114167 | SHORT PROTECTION CONTROL CIRCUITS AND RELATED CONTROL METHODS - Short protection control circuits and related control methods are disclosed. A disclosed short protection control circuit is adapted for controlling a short protection mechanism providing short protection to several LED chains. The disclosed short protection control circuit has a detection circuit, a first logic circuit and a timer. Coupled to the LED chains, the detection circuit asserts an indication signal when one of the node voltages of the LED chains is lower than an under-current reference. When the indication signal is enabled, the first logic circuit starts blocking the short protection mechanism. The timer times to provide a result when the short protection mechanism is blocked. When the result indicates that the short protection mechanism has been blocked for at least a predetermined time period, the first logic circuit resumes the short protection mechanism. | 05-09-2013 |
20130094254 | METHODS AND POWER CONTROLLERS FOR PRIMARY SIDE CONTROL - Power controllers and related primary-side control methods are disclosed. A disclosed power controller has a comparator and an ON-triggering controller. The comparator compares a feedback voltage with an over-shot reference voltage. Based on an inductance-coupling effect, the feedback voltage represents a secondary-side voltage of a secondary winding. Coupled to the comparator, the ON-triggering controller operates a power switch at about a first switching frequency when the feedback voltage is lower than the over-shot reference voltage. The ON-triggering controller operates the power switch at about a second switching frequency when the feedback voltage exceeds the over-shot reference voltage. The second switching frequency is less than the first switching frequency. | 04-18-2013 |
20130093327 | CONTROL METHODS FOR LED CHAINS - Control methods for driving LED chains. An output power is provided to drive the LED chains. Short protections are provided to the LED chains, respectively. Whether at least one of the LED chains encounters an under-current event is detected. If any one of the LED chains encounters the under-current event, all short protections are stopped. Whether the output power reaches safe requirement is detected. After the output power reaches the safe requirement, the short protection corresponding to a normal LED chain is resumed. The normal LED chain refers to one of the LED chains that does not encounter the under-current event. | 04-18-2013 |
20130088206 | POWER CONTROLLER AND POWER MANAGEMENT CONTROL METHOD - A power controller includes a clock generator, a low-frequency clock generator, and a protection circuit. The clock generator provides a clock signal with a clock frequency for periodically switching on and off a power switch. The low-frequency clock generator provides a low-frequency clock signal with a frequency lower than the clock frequency. The protection circuit includes an over-power detection circuit and a logic circuit. The over-power detection circuit determines whether an over power event has occurred according to a feedback signal controlled by an output voltage of the power supply. When the over power event lasts longer than an over power tolerance duration, the logic circuit isolates the power switch from the clock signal to keep the power switch turned off. The over power tolerance duration is equal to a predetermined clock cycles of the low-frequency clock signal. | 04-11-2013 |
20130088158 | LIGHT EMITTING DIODE DRIVING INTEGRATED CIRCUIT WITH A MULTI-STEP CURRENT SETTING FUNCTION AND METHOD OF SETTING A MULTI-STEP CURRENT OF A LIGHT EMITTING DIODE DRIVING INTEGRATED CIRCUIT - A light emitting diode driving integrated circuit with a multi-step current setting function includes a regulator circuit, a variable resistor circuit, and a current generation unit. The regulator circuit provides a supply voltage to a first terminal of at least one series of light emitting diodes to drive the at least one series of light emitting diodes, and regulates a second terminal voltage of the at least one series of light emitting diodes to a target voltage. The variable resistor circuit is used for changing a resistance of the variable resistor circuit in a plurality of steps according to a switching signal. The current generation unit is coupled to the variable resistor circuit for changing current flowing through the at least one series of light emitting diodes in a plurality of steps according to a reference voltage and variation of the resistance of the variable resistor circuit. | 04-11-2013 |
20130083562 | POWER SUPPLY, POWER MANAGEMENT DEVICE APPLIED TO A POWER SUPPLY, AND METHOD FOR PERFORMING BROWN-OUT PROTECTION AND OVERHEAT PROTECTION OF A POWER MANAGEMENT DEVICE - A power supply can provide brown-out protection and overheat protection. The power supply includes a rectifier, a transformer, and a power management device. The rectifier is used for receiving an alternating current voltage. The alternating current voltage has a voltage cycle. The transformer coupled to the rectifier has an inductor coupled to a switch for supplying an output voltage. The power management device is used for controlling the switch to make the inductor save power or release power. The power management device has a multi-functional pin coupled to the rectifier for receiving a detection voltage corresponding to a positive half cycle of the alternating current voltage. The multi-functional pin is also coupled to a thermistor for receiving an overheat protection signal. | 04-04-2013 |
20110032024 | Integrated Circuit and Related Method for Determining Operation Modes - An integrated circuit and a related method for determining an operation mode are disclosed. The exemplified integrated circuit includes a controller, a multi-function pin, and a mode determination circuit. The controller controls a power switch and is being set to operate in one of the operation modes including a first operation mode and a second operation mode. The multi-function pin is connected to an external resistor. The mode determination circuit detects a signal from the multi-function pin. The signal represents the resistance of the external resistor. If the resistance is within a first range, the controller is operated in the first operation mode. If the resistance is within a second range, the controller is operated in the second operation mode. | 02-10-2011 |
20090097281 | LEAKAGE-INDUCTANCE ENERGY RECYCLING CIRCUIT AND FLYBACK CONVERTER WITH LEAKAGE-INDUCTANCE ENERGY RECYCLING CIRCUIT - A flyback converter with a leakage-inductance energy recycling circuit includes a transformer and a leakage-inductance energy recycling circuit. The leakage-inductance energy recycling circuit includes a clamping circuit, an energy storage circuit, and a switch connected between the clamping circuit and the energy storage circuit. A power transistor is electrically connected to a primary winding of the transformer. The clamping circuit clamps the voltage of the power transistor at a predetermined voltage. The energy storage circuit stores the leakage-inductance energy of the primary winding. When the switch is turned off, the clamping circuit receives and stores the leakage-inductance energy of the primary winding, so as to clamp the voltage of the power transistor to a predetermined voltage; when the switch is turned on, the energy stored in the clamping circuit is stored in the energy storage circuit through the switch. | 04-16-2009 |
20090016413 | PSEUDO RANDOM CLOCK GENERATOR - A pseudo random clock generator includes a clock generator for generating a clock signal. A pseudo random code generator receives the clock signal and thereby generating a pseudo random code. A code limiter enables the value of the pseudo random code being unchanged for at least two periods of the clock signal. A logic gate applies a logic operation to the pseudo random code and the clock signal and thereby outputting a pseudo random clock. | 01-15-2009 |