Abstract: A control circuit applied to a power converter includes a multi-functional pin, a zero-crossing signal generator, and an over-voltage detector. The multi-functional pin is used for receiving an auxiliary current generated by an auxiliary winding of the power converter, and an input current. The zero-crossing signal generator is used for generating a zero-crossing signal according to the auxiliary current. The over-voltage detector is used for generating an over-voltage signal according to the auxiliary current. The control circuit generates a switch control signal to the power switch according to the zero-crossing signal, or generates an over-voltage protection signal to the power switch according to the over-voltage signal.

Abstract: Power supplies together with related over voltage protection methods and apparatuses. A power supply has a transformer including a primary winding and an auxiliary winding. A power switch is coupled to the primary winding and a sensing resistor coupled between the power switch and a grounding line. A multi-function terminal of a controller is coupled to the sensing resistor. A diode and a first resistor is coupled between the auxiliary winding and the multi-function terminal.

Abstract: An oscillator applied to a control circuit of a power converter includes a compensation module and an oscillation module. The compensation module outputs or sinks an adjustment current according to a compensation voltage corresponding to a load, a direct current voltage of a primary side of the power converter, and a reference voltage. The oscillation module outputs a clock signal according to the compensation voltage, a control voltage, and the adjustment current. The control circuit generates a gate control signal to a power switch of the primary side according to the clock signal. When the compensation voltage is less than a first predetermined voltage, a frequency of the gate control signal is a first fixed value, and when the compensation voltage is between the first predetermined voltage and a second predetermined voltage and greater than the second predetermined voltage, the frequency is varied with the compensation voltage.

Abstract: A controller with leakage current protection of a diode includes a comparison unit, a reference voltage generation unit, a time out signal generation unit, and a gate signal generation unit, wherein the diode is applied to a secondary side of a power converter. The comparison unit outputs a corresponding selection signal according to a compensation voltage and a threshold. The reference voltage generation unit outputs a corresponding reference voltage range according to the corresponding selection signal. The time out signal generation unit determines a corresponding time out according to the corresponding selection signal, and generates a corresponding time out signal when a voltage corresponding to an auxiliary winding has no peak to cross an upper limit of the corresponding reference voltage range during the corresponding time out. The gate signal generation unit enters the leakage current protection or a quasi-resonant mode according to the corresponding time out signal.

Abstract: A controller for dimming light-emitting diodes includes a pulse width modulation pin, a low-pass filter, a frequency detection unit, and a control signal generation module. The low-pass filter generates a direct current signal according to a pulse width modulation signal generated by a micro-controller. The frequency detection unit generates a logic value according to a threshold and the pulse width modulation signal. The control signal generation module generates a switch control signal to a first switch connected to the light-emitting diodes in series according to the direct current signal, the logic value, a reference voltage, and the pulse width modulation signal. When a frequency of the pulse width modulation signal is lower than the threshold, the controller enters a digital dimming mode; and when the frequency of the pulse width modulation signal is higher than the threshold, the controller enters an analog dimming mode.

Abstract: A controller for eliminating acoustic noise of a power converter includes a control unit and a gate signal generation unit. The control unit is used for detecting a frequency corresponding to a gate control signal in a burst mode of the power converter. When the frequency is greater than a predetermined frequency, the control unit increases a resistance of a compensation resistor coupled to a compensation pin of the power converter; and when the frequency is less than the predetermined frequency, the control unit decreases the resistance of the compensation resistor. The gate signal generation unit is coupled to the control unit for generating the gate control signal to a power switch of a primary side of the power converter according to the resistance of the compensation resistor. The power switch is turned on according to the gate control signal.

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: A controller for adjusting an output voltage of a power converter includes a gate control signal generation circuit, a feedback signal detection module, and a reference voltage generation module. The gate control signal generation circuit generates a gate control signal to a power switch of a primary side of the power converter according to a reference voltage and a plurality of signals corresponding to the primary side and a secondary side of the power converter. The feedback signal detection module generates a logic signal according to a combination corresponding to the plurality of signals. The reference voltage generation module generates the reference voltage to the gate control signal generation circuit according to the logic signal. The power switch adjusts the output voltage of the secondary side of the power converter according to the gate control signal.

Abstract: 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.

Abstract: 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.

Abstract: A power supply has an inductor and determines loading state of the power supply according to a compensation signal. When the loading state is determined to be a light loading state or a no-loading state, a switch is operated at a low operating frequency. When the loading state is determined to be a heavy loading state, the switch is operated at a high operating frequency. If the compensation signal exceeds a critical value, it is determined that the loading state is an overloaded state. When the overloaded state continues past a tolerable duration, the switch is turned off. The tolerable duration is determined by an external capacitor and is independent of the operating frequency.

Abstract: A control circuit includes an auxiliary pin for receiving an auxiliary voltage of an auxiliary winding of a power converter; a first detection unit for detecting a first time point when the auxiliary voltage begins resonance, and outputting a first detection signal according to the first time point; a second detection unit for detecting a second time point when the auxiliary voltage reaches a predetermined voltage, and outputting a second detection signal according to the second time point; a delay time controller for obtaining a delay time according to a output time difference between the first detection signal and the second detection signal, and outputting a driving signal with delay of the delay time when receiving the second detection signal; and a gate control signal generator for generating a gate control signal to a power switch of the power converter according to the driving signal of the delay time controller.

Abstract: 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.

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 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.

Abstract: A control circuit for reducing touch current of a power converter includes an auxiliary pin, a zero-crossing signal generator, a frequency limiting signal generator, and a gate signal generator. The auxiliary pin is used for receiving a voltage generated by an auxiliary winding of the power converter. The zero-crossing signal generator is used for generating a zero-crossing signal according to the voltage generated by the auxiliary winding and a first reference voltage. The frequency limiting signal generator is used for generating a frequency limiting signal according to a gate control signal, a burst mode signal, and the voltage generated by the auxiliary winding. The frequency limiting signal is used for limiting the gate control signal to a predetermined frequency. The gate signal generator is used for generating the gate control signal to a power switch of the power converter according to the frequency limiting signal and the zero-crossing signal.

Abstract: 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.

Abstract: A capacitance amplifying circuit applied to a controller of a power convertor includes a comparison unit and a capacitance amplifying module. The comparison unit receives a feedback voltage corresponding to a load coupled to the power convertor, a dimming signal, and a reference voltage, and outputs a compensation current. The capacitance amplifying module generates an equivalent capacitor. A capacitance of the equivalent capacitor is K times to a capacitance of a reference capacitor of the capacitance amplifying module, and K is a real number greater than 1. The compensation current and the equivalent capacitor are used for determining a compensation voltage, and when the dimming signal is disabled, a closed loop within the capacitance amplifying module is changed to an open loop to keep the compensation voltage at a fixed value.

Abstract: 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.

Abstract: 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.