Abstract: The disclosure provides a power controller and related control method for a switch mode power supply operating in a quasi-resonant mode. The switched mode power supply has a power switch and an auxiliary winding. The power controller has a feedback pin connected to the auxiliary winding. A clamp circuit is connected to the feedback pin and configured for clamping a voltage at the feedback pin by providing a clamp current. A peak hold circuit is connected to the clamp circuit for generating a peak record substantially corresponding to a peak value of the clamp current. A valley detector is configured for providing an entry signal indicating a start of a voltage valley. A delay circuit provides a trigger signal a delay time after the entry signal is provided. The delay time varies in response to the peak record, and the trigger signal is capable of turning on the power switch.

Abstract: A controller for generating jitters in a quasi resonant mode includes a feedback pin, a voltage generation unit, a pulse generator, and a comparator. The feedback pin is used for receiving a feedback voltage from a secondary side of a power converter. The voltage generation unit is used for generating a first voltage according to the feedback voltage and a pulse. The pulse generator is used for generating the pulse when a control signal controlling a power switch of a primary side of the power converter is enabled. The comparator is used for controlling enabling and disabling of a switching signal according to the first voltage and a variable reference voltage. The variable reference voltage is monotonously swung within a predetermined range according to a digital signal.

Abstract: Disclosed include a control circuit adapted for a power controller powered by an operation voltage. When the operation voltage exceeds an over-voltage reference, the power controller stops power conversion provided by a power converter. The control circuit comprises a slope detector detecting a variation slope of the operation voltage. When the variation slope exceeds a drop rate, the slope detector recovers the power conversion. When the power conversion is recovered the power controller compares the operation voltage with the over-voltage reference.

Abstract: 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 0<K<1.

Abstract: 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.

Abstract: A frequency-jittering apparatuses includes an oscillator and a frequency control circuit. The oscillator generates a signal. When the magnitude of the signal exceeds a magnitude of a reference signal, the oscillator operates substantially in a first state; and when the magnitude of the signal is lower than the magnitude of the reference signal, the oscillator operates substantially in a second state different from the first one. The frequency control circuit varies the reference signal to change the frequency of the signal output from the oscillator.

Abstract: 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 0<K<1.

Abstract: Discloses are a constant current control unit and a control method, apt to a switched mode power supply with primary side control. The switched mode power supply comprises a power switch and an inductive device. A reflective voltage of the inductive device is detected to generate a feedback voltage signal. By delaying the feedback voltage signal, a delayed signal is generated. According to the feedback voltage and the delayed signal determining, a discharge time of the inductive device is determined when the power switch is OFF. According to the discharge time and a current-sense signal, a maximum average output current of the switched mode power supply is stabilized. The current-sense signal represents a current flowing through the inductive device.

Abstract: Embodiments disclose control methods and control apparatuses for a switched mode power supply. The switched mode power supply comprises a current-controllable device. A driving current is provided to turn ON the current-controllable device. A conduction current passing through the current-controllable device is detected. The driving current is controlled according to the conduction current. The higher the conduction current the higher the driving current.

Abstract: 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.

Abstract: Disclosure includes control methods and power controllers with load compensation adapted for a power supply powering a load. A disclosed power controller comprises a converter and a control circuit. The converter converts the load signal at a first node to output a load-compensation signal at a second node. The load signal corresponds to an output power provided from the power supply to the load, and the converter includes a low-pass filter coupled between the first and second nodes. The control circuit is coupled to an inductive device via a feedback node, for controlling the output power to make a cross voltage of the inductive device approach a target voltage, based on a feedback voltage at the feedback node. The higher the load-compensation signal the higher the target voltage.

Abstract: Disclosed include a control circuit adapted for a power controller powered by an operation voltage. When the operation voltage exceeds an over-voltage reference, the power controller stops power conversion provided by a power converter. The control circuit comprises a slope detector detecting a variation slope of the operation voltage. When the variation slope exceeds a drop rate, the slope detector recovers the power conversion. When the power conversion is recovered the power controller compares the operation voltage with the over-voltage reference.

Abstract: A method for controlling voltage crossing a power switch of a switched-mode power converter is disclosed. The method comprises the steps of: controlling a switch frequency of a power switch of a switched-mode power converter to a first frequency as activating the switched-mode power converter; and changing the switch frequency of the power switch to a second frequency after a specific amount of time; wherein the first frequency is lower than the second frequency.

Abstract: 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.

Abstract: A frequency-jittering apparatuses includes an oscillator and a frequency control circuit. The oscillator generates a signal. When the magnitude of the signal exceeds a magnitude of a reference signal, the oscillator operates substantially in a first state; and when the magnitude of the signal is lower than the magnitude of the reference signal, the oscillator operates substantially in a second state different from the first one. The frequency control circuit varies the reference signal to change the frequency of the signal output from the oscillator.

Abstract: A frequency-jittering apparatuses includes an oscillator and a frequency control circuit. The oscillator generates a signal. When the magnitude of the signal exceeds a magnitude of a reference signal, the oscillator operates substantially in a first state; and when the magnitude of the signal is lower than the magnitude of the reference signal, the oscillator operates substantially in a second state different from the first one. The frequency control circuit varies the reference signal to change the frequency of the signal output from the oscillator.

Abstract: 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.

Abstract: A frequency-jittering apparatuses includes an oscillator and a frequency control circuit. The oscillator generates a signal. When the magnitude of the signal exceeds a magnitude of a reference signal, the oscillator operates substantially in a first state; and when the magnitude of the signal is lower than the magnitude of the reference signal, the oscillator operates substantially in a second state different from the first one. The frequency control circuit varies the reference signal to change the frequency of the signal output from the oscillator.

Abstract: An AC/DC power supply with over-voltage protection includes a voltage converting circuit and a digital latch control circuit. The voltage converting circuit has a first-side winding, a second-side winding, and an auxiliary winding for providing a supply voltage according to the AC input voltage. The digital latch control circuit is coupled to the voltage converting circuit and utilized for latching a voltage level of the supply voltage at a first predetermined level according to an over-voltage protection (OVP) trigger signal, where the voltage converting circuit is disabled when the voltage level is latched at the first predetermined level.

Abstract: A light emitting device driving circuit, includes: a switch device, a comparator, a driving module, a time counting circuit and a compensation module. The switch device is turned on or off according to a control signal for controlling a driving current flowing through the light emitting device. The comparator generates a comparison result according to a reference voltage and a feedback voltage corresponding to the driving current. The driving module generates the control signal according to the comparison result. The time counting circuit controls the driving module to turn on the switch device after the switch device turns off for a predetermined time. The compensation module detects a turn on time for the switch device and a delay time between the feedback voltage reaching the reference voltage value and the control signal varying correspondingly, and adjusts the reference voltage according to the turn on time and the delay time.