Abstract: A power conversion apparatus and a synchronous rectification (SR) controller thereof are provided. An open-loop control circuit outputs a clamp voltage as a driving voltage when a drain voltage of a synchronous rectification transistor rises to a second voltage, so as to quickly pull down the driving voltage and maintain the driving voltage at a clamp voltage. Therefore, a second control circuit may quickly turn off the synchronous rectification transistor when the drain voltage is greater than a third voltage.

Abstract: A power supply apparatus and a discharge method thereof are provided. A control unit detects a cross-voltage across two ends of an AC safety capacitor to generate a detection voltage, compares the detection voltage with a threshold voltage, counts the number of cycles of the detection voltage during a period when the detection voltage does not cross the threshold voltage according to a comparison result between the detection voltage and the threshold voltage, and performs a discharge operation when the number of cycles is greater than or equal to a predetermined value to discharge electric energy stored in the AC safety capacitor.

Abstract: A power conversion apparatus and a charging method of the power conversion apparatus are provided. A synchronous rectifier controller provides a voltage of a drain terminal of a synchronous rectifier transistor to charge a capacitor of a power supply terminal of the synchronous rectifier controller when the synchronous rectifier transistor is turned from an on state to an off state and a voltage of the power supply terminal is less than a preset voltage.

Abstract: A voltage conversion apparatus and a voltage conversion method thereof are provided. A conversion circuit converts outputs of a plurality of secondary windings to generate a conversion voltage or a conversion current to a resistor network of a feedback circuit to thereby change impedance characteristics of the resistor network. The feedback circuit adjusts a feedback voltage in response to the change in the impedance characteristics of the resistor network, so that a control circuit controls an output of a transformer circuit according to the feedback voltage.

Abstract: A power conversion apparatus and a charging method of the power conversion apparatus are provided. A synchronous rectifier controller provides a voltage of a drain terminal of a synchronous rectifier transistor to charge a capacitor of a power supply terminal of the synchronous rectifier controller when the synchronous rectifier transistor is turned from an on state to an off state and a voltage of the power supply terminal is less than a preset voltage.

Abstract: A voltage conversion apparatus for implementing zero-voltage switching based on recovering leakage inductance energy is provided. A leakage inductance energy recovery circuit is coupled to a primary side auxiliary winding and a control circuit, and recovers leakage inductance energy of a transformer circuit to supply an operating power to the control circuit. Before a main switch is turned on the next time, leakage inductance energy recovered previously is used to lower a cross-voltage of the main switch, so that transient loss of conduction of the main switch is eliminated or reduced, and circuit efficiency is improved.

Abstract: A voltage conversion apparatus and a voltage conversion method thereof are provided. A conversion circuit converts outputs of a plurality of secondary windings to generate a conversion voltage or a conversion current to a resistor network of a feedback circuit to thereby change impedance characteristics of the resistor network. The feedback circuit adjusts a feedback voltage in response to the change in the impedance characteristics of the resistor network, so that a control circuit controls an output of a transformer circuit according to the feedback voltage.

Abstract: An LED backlight system and an LED control circuit are provided. The LED backlight system includes an LED string and the LED control circuit. The LED control circuit includes an LED driver, a switching circuit and an abnormality detecting circuit. The LED driver is configured to generate a control signal. The switching circuit controls a current flowing through the LED string in response to the control signal. The abnormality detecting circuit is configured to detect a voltage or the current of a first end of the LED string. When the voltage or the current of the first end of the LED string is less than or equal to a threshold value, the abnormality detecting circuit turns off the switching circuit, and the abnormality detecting circuit detects an impedance of the first end of the LED string to determine an abnormal state of the LED string.

Abstract: A pulse width modulation control circuit and a control method of a pulse width modulation signal are provided. A counter circuit generates a count value according to a phase-locked loop clock, and resets the count value according to a transition point of a synchronization signal. A comparison circuit compares the count value with a duty ratio set value, and sets the pulse width modulation signal to a high level while the count value is less than the duty ratio set value.

Abstract: A pulse width modulation control circuit and a control method of a pulse width modulation signal are provided. A counter circuit generates a count value according to a phase-locked loop clock, and resets the count value according to a transition point of a synchronization signal. A comparison circuit compares the count value with a duty ratio set value, and sets the pulse width modulation signal to a high level while the count value is less than the duty ratio set value.

Abstract: A voltage conversion apparatus is provided. A leakage inductance energy recovery circuit is coupled to a primary side auxiliary winding and a control circuit, and recovers leakage inductance energy of a transformer circuit to supply an operating power to the control circuit. Before a main switch is turned on the next time, leakage inductance energy recovered previously is used to lower a cross-voltage of the main switch, so that transient loss of conduction of the main switch is eliminated or reduced, and circuit efficiency is improved.

Abstract: An LED backlight system and an LED control circuit are provided. The LED backlight system includes an LED string and the LED control circuit. The LED control circuit includes an LED driver, a switching circuit and an abnormality detecting circuit. The LED driver is configured to generate a control signal. The switching circuit controls a current flowing through the LED string in response to the control signal. The abnormality detecting circuit is configured to detect a voltage or the current of a first end of the LED string. When the voltage or the current of the first end of the LED string is less than or equal to a threshold value, the abnormality detecting circuit turns off the switching circuit, and the abnormality detecting circuit detects an impedance of the first end of the LED string to determine an abnormal state of the LED string.

Abstract: A light emitting diode driving device and a light emitting diode backlight module are provided. A current is provided to a filter circuit by a controllable current source controlled by a dimming signal, so that the filter circuit generates a corresponding dimming voltage to control current flowing through a LED unit to dim the LED unit.

Abstract: A light emitting diode driving device and a light emitting diode backlight module are provided. A current is provided to a filter circuit by a controllable current source controlled by a dimming signal, so that the filter circuit generates a corresponding dimming voltage to control current flowing through a LED unit to dim the LED unit.

Abstract: A power conversion apparatus including a synchronous rectification (SR) transistor, a SR controller and a snubber circuit is provided. The SR controller is coupled to the SR transistor to control the SR transistor. A ground terminal of the SR controller is coupled to a source terminal of the SR transistor, and a power terminal of the SR controller is coupled to a system voltage. A first terminal of the snubber circuit is coupled to a drain terminal of the SR transistor. A second terminal of the snubber circuit is coupled to the power terminal of the SR controller. The snubber circuit obtains power from the drain terminal of the SR transistor and provides the system voltage accordingly.

Abstract: A power conversion apparatus and a synchronous rectification (SR) circuit thereof are provided. The power conversion apparatus includes a transformer and the SR circuit. A primary winding of the transformer receives an input voltage. A secondary winding of the transformer provides an output voltage to an output terminal. The SR circuit includes a SR transistor and a SR controller. The SR transistor is coupled between the secondary winding and the output terminal and controlled by a control signal. The SR controller is coupled to the SR transistor to receive a first detecting signal, and generates the control signal according to the first detecting signal. When the SR controller detects that the SR circuit is abnormal, the SR controller generates the controller signal to keep the SR transistor at an on state so as to perform an abnormal protection on the SR circuit.

Abstract: A power conversion apparatus and a synchronous rectification (SR) circuit thereof are provided. The power conversion apparatus includes a transformer and the SR circuit. A primary winding of the transformer receives an input voltage. A secondary winding of the transformer provides an output voltage to an output terminal. The SR circuit includes a SR transistor and a SR controller. The SR transistor is coupled between the secondary winding and the output terminal and controlled by a control signal. The SR controller is coupled to the SR transistor to receive a first detecting signal, and generates the control signal according to the first detecting signal. When the SR controller detects that the SR circuit is abnormal, the SR controller generates the controller signal to keep the SR transistor at an on state so as to perform an abnormal protection on the SR circuit.

Abstract: A power conversion apparatus and a synchronous rectification (SR) controller thereof are provided. The SR controller includes a first control circuit, a second control circuit, a pull-up circuit and a pull-down circuit. The first control circuit generates a pull-up control signal and a first pull-down signal according to a drain voltage of an SR transistor and a first voltage. The second control circuit compares the drain voltage with a second voltage to generate a second pull-down signal, and selects one of the first pull-down signal and the second pull-down signal as a pull-down control signal. The pull-up circuit and the pull-down circuit regulate a driving voltage on a gate terminal of the SR transistor in response to the pull-up control signal and the pull-down control signal respectively.

Abstract: A power conversion apparatus and a synchronous rectification (SR) controller thereof are provided. The SR controller includes a first control circuit, a second control circuit and a third control circuit. The first control circuit compares a drain voltage on a drain terminal of a SR transistor with a first voltage. When the drain voltage is lower than the first voltage, the first control circuit outputs a driving voltage to turn on the SR transistor. The second control circuit generates the driving voltage according to the drain voltage and a second voltage so as to control the SR transistor. The third control circuit compares the drain voltage with a third voltage. When the drain voltage is higher than the third voltage, the third control circuit outputs the driving voltage to turn off the SR transistor.

Abstract: A power conversion apparatus is provided. A detecting circuit detects a current flowing into a boot voltage input pin and converts the current into a corresponding detecting voltage. An adjusting signal generating circuit generates an adjusting signal according to the detecting voltage. A control circuit adjusts control parameters thereof according to the adjusting signal.