Abstract: A power converter includes a switch control circuit for driving a high side switch of the power converter comprising the high side switch and a low side switch connected in series. The switch control circuit may have a first terminal for receiving an input signal, a second terminal used as a reference ground terminal of the switch control circuit, and a third terminal used as an output terminal to provide a driving signal, the switch control circuit can draw power from the input signal and may be configured to control a logic state of the driving signal based on a logic state of the input signal relative to a reference ground signal at the second terminal or based on a current flowing through the first terminal.

Abstract: A control circuit for a power converter. The control circuit may provide a first switch driving signal and a second switch driving signal that may be respectively used to control a first power switch and a second power switch. The control circuit may change the second switch driving signal from a second driving reset logic state to a second driving set logic state after a dead time expires since a moment when the first switch driving signal is changed from a first driving set logic state to a first driving reset logic state. The control circuit may further adaptively adjust the dead time to vary in a same direction as a capacitance parameter of the first power switch and a capacitance parameter of the second power switch vary.

Abstract: A method for detecting a variation of input voltage. The method is generating an indication signal based on the input voltage, and comparing the input voltage with a first reference signal. The first reference signal is smaller than the indication signal, and if the input voltage is consistently smaller than the first reference signal during a first time duration from the moment when the input voltage is decreased to the first reference signal, the indication signal is decreased after the first time duration.

Abstract: A control circuit for a switching converter. The control circuit includes a first pin and a secondary control circuit with a transmitter. The secondary control circuit determines whether to enter a low power mode from a normal power mode based on a voltage at the first pin. The transmitter is configured to modulate a secondary sync signal and to transmit the modulated secondary sync signal to a primary control circuit when the secondary control circuit is in the normal power mode and configured to be disabled when the secondary control circuit is in the low power mode.

Abstract: A controller for a switching converter with a power switch includes a gate driver, a first transistor, and a regulator. The gate driver and provides a drive voltage to control the power switch based on a switch control signal. The first transistor is coupled between a first power supply node and a power supply terminal of the gate driver. A current sense signal representative of a current flowing through the power switch is provided to a floating node in response to the switch control signal being a first level, and the floating node is coupled to a reference ground in response to the switch control signal being a second level. A gate voltage of the first transistor is adjusted by the regulator coupled to the floating node based on a float reference voltage and a feedback voltage provided by a feedback stage.

Abstract: A control circuit for controlling a power supply voltage of an integrated circuit is provided. The control circuit includes a charging current source. The charging current source receives an input voltage and provides a charging current to a power supply capacitor for generating the power supply voltage. The charging current source starts providing the charging current for charging the power supply capacitor when the input voltage decreases to a charging start threshold voltage and stops providing the charging current when the power supply voltage increases to a charging stop reference voltage. The charging start threshold voltage is adjusted to get a continuous time duration of providing the charging current to be substantially symmetric with respect to a minimum value of the input voltage.

Abstract: A control circuit for controlling a power supply voltage is provided. The control circuit includes a charging control circuit and a charging current source. The charging control circuit provides a charging control signal based on an input voltage and the power supply voltage. The charging current source receives the input voltage and provides a charging current to a power supply capacitor for generating the power supply voltage based on the charging control signal. In a charging window, the charging control signal controls the charging current source to start providing the charging current for charging the power supply capacitor after a first time-interval from a start point of the charging window. The charging control signal controls the charging current source to stop providing the charging current when the power supply voltage increases to a charging stop reference voltage. A continuous time duration of providing the charging current is a charging period.

Abstract: A control circuit for a power converter. The control circuit may provide a first switch driving signal and a second switch driving signal that may be respectively used to control a first power switch and a second power switch. The control circuit may change the second switch driving signal from a second driving reset logic state to a second driving set logic state after a dead time expires since a moment when the first switch driving signal is changed from a first driving set logic state to a first driving reset logic state. The control circuit may further adaptively adjust the dead time to vary in a same direction as a capacitance parameter of the first power switch and a capacitance parameter of the second power switch vary.

Abstract: A synchronous rectifier control circuit, used with a synchronous rectification circuit having a primary switch and a synchronous rectifier, having: a drain-source threshold setting circuit, configured to provide a dynamic drain-source voltage threshold based on a drain-source voltage across the synchronous rectifier; a primary switch detecting circuit, configured to provide a primary switch state indicating signal based on a comparison result of the drain-source voltage and the dynamic drain-source voltage threshold; and an on-control circuit, configured to provide a synchronous on signal to turn on the synchronous rectifier when the drain-source voltage decreases to the turn-on threshold, on the premise that the primary switch state indicating signal indicates an on state of the primary switch.

Abstract: A power converter includes a switch control circuit for driving a high side switch of the power converter comprising the high side switch and a low side switch connected in series. The switch control circuit may have a first terminal for receiving an input signal, a second terminal used as a reference ground terminal of the switch control circuit, and a third terminal used as an output terminal to provide a driving signal, the switch control circuit can draw power from the input signal and may be configured to control a logic state of the driving signal based on a logic state of the input signal relative to a reference ground signal at the second terminal or based on a current flowing through the first terminal.

Abstract: A switching mode power supply preventing a first switch from being falsely triggered. The switching mode power supply detects a peak of an input signal and starts timing a period of time since the arrival of the peak of the input signal is detected. The first switch starts performing the on and off switching operations when the period of time expires.

Abstract: A discharge circuit for an X capacitor has a first voltage detection circuit providing a first indicating signal based on a voltage across two input terminals of a switching converter to indicate whether the two input terminals are connected to an AC power source, and a discharge module starting a discharge operation on the X capacitor based on first indicating signal, and the discharge operation discharges the X capacitor during a first time period, and stops discharging the X capacitor and compares a sampled signal with the voltage across the two input terminals during a following second time period.

Abstract: A switching mode power supply with an adaptive setting of a threshold valley voltage. The switching mode power supply decreases a reference auxiliary current when a valley value of a primary switching voltage across a primary switch is smaller than a first threshold valley voltage. And in addition, the switching mode power supply can increase the reference auxiliary current when the valley value of the primary switching voltage is larger than a second threshold valley voltage.

Abstract: A method for detecting a variation of input voltage. The method is generating an indication signal based on the input voltage, and comparing the input voltage with a first reference signal. The first reference signal is smaller than the indication signal, and if the input voltage is consistently smaller than the first reference signal during a first time duration from the moment when the input voltage is decreased to the first reference signal, the indication signal is decreased after the first time duration.

Abstract: A driving circuit for driving a synchronous rectifier device. The driving circuit may include a controllable charging circuit and a slope sensing circuit. The slope sensing circuit may sense whether an abrupt rising change in a voltage drop from a sensing terminal to a reference ground terminal of the driving circuit is occurring, and provide a slope sensing signal in response to a rising edge of the abrupt rising change in the voltage drop. The controllable charging circuit may receive the slope sensing signal and provide a charging current to a supply terminal of the driving circuit in response to each rising edge of the abrupt rising change in the voltage drop.

Abstract: A synchronous rectifier control circuit, used with a synchronous rectification circuit having a primary switch and a synchronous rectifier, having: a drain-source threshold setting circuit, configured to provide a dynamic drain-source voltage threshold based on a drain-source voltage across the synchronous rectifier; a primary switch detecting circuit, configured to provide a primary switch state indicating signal based on a comparison result of the drain-source voltage and the dynamic drain-source voltage threshold; and an on-control circuit, configured to provide a synchronous on signal to turn on the synchronous rectifier when the drain-source voltage decreases to the turn-on threshold, on the premise that the primary switch state indicating signal indicates an on state of the primary switch.

Abstract: A driving circuit for driving a synchronous rectifier device. The driving circuit may include a controllable clamping circuit having a first terminal coupled to a sensing terminal of the driving circuit, a second terminal coupled to a reference ground terminal of the driving circuit, a third terminal coupled to a driving terminal of the driving circuit, and a control terminal configured to receive a supply indication signal indicative of a voltage potential at a supply terminal of the driving circuit. The third terminal of the controllable clamping circuit may be connected to the second terminal of the controllable clamping circuit when the supply indication signal indicates that the voltage potential at the supply terminal has not been established to maintain the synchronous rectifier device off.

Abstract: A switching mode power supply preventing false triggering of an over current protection due to a surge pulse. The switching mode power supply has a switch and an inductor. An inductor current flows through the inductor. The switching mode power supply turns off the switch and meanwhile starts timing for a preset period of time when the inductor current is larger than a preset value. The switch is kept off during the preset period of time and is then turned on when the preset period of time expires.

Abstract: A switching mode power supply with an adaptive setting of a threshold valley voltage. The switching mode power supply decreases a reference auxiliary current when a valley value of a primary switching voltage across a primary switch is smaller than a first threshold valley voltage. And in addition, the switching mode power supply can increase the reference auxiliary current when the valley value of the primary switching voltage is larger than a second threshold valley voltage.

Abstract: A driving circuit for driving a synchronous rectifier device. The driving circuit may include a controllable charging circuit and a slope sensing circuit. The slope sensing circuit may sense whether an abrupt rising change in a voltage drop from a sensing terminal to a reference ground terminal of the driving circuit is occurring, and provide a slope sensing signal in response to a rising edge of the abrupt rising change in the voltage drop. The controllable charging circuit may receive the slope sensing signal and provide a charging current to a supply terminal of the driving circuit in response to each rising edge of the abrupt rising change in the voltage drop.