Abstract: A controller of a power converter includes a sample-and-hold unit and an adjustment unit, wherein the power converter is applied to a Universal Serial Bus power delivery adapter system. The sample-and-hold unit is used for sampling a voltage to generate a sampling voltage during each period of a gate control signal, wherein the sampling voltage corresponds to an output voltage of the power converter. The adjustment unit is coupled to the sample-and-hold unit for adjusting at least one of a frequency of the gate control signal, a current flowing through a primary side of the power converter, and a resistance of a compensation resistor of the controller according to the sampling voltage.

Abstract: A power converter provides a dummy load to lower an output voltage under a light-load or no-load condition. The power converter has a primary winding and a secondary winding isolated from each other. The secondary winding can de-energize to provide the output voltage at an output node for powering a load. The winding voltage at across the secondary winding is sensed to provide a non-switching time, which is checked if it exceeds a predetermined reference time. The output voltage is compared with a predetermined voltage. A discharge current is provided as the dummy load to drain from the output node and to lower the output voltage if the on-switching time exceeds the predetermined reference time and the output voltage exceeds the predetermined voltage.

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: Control methods and related power controllers diminish audible noise in a power supply capable of performing valley switching. The power supply has an inductive device and a power switch. When the power switch is OFF, a winding voltage of the inductive device oscillates to provide an oscillation signal with at least one signal valley. An occurrence number of the signal valley is detected, and is compared with a lock number. When the occurrence number and the lock number fit a predetermined condition, the power switch is turned ON to start a cycle time at a start moment. Whether the start moment falls within an expectation window is checked. The lock number is changed if the start moment falls outside of the expectation window.

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 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 start-up circuit to discharge EMI filter is developed for power saving. It includes a detection circuit detecting a power source for generating a sample signal. A sample circuit is coupled to the detection circuit for generating a reset signal in response to the sample signal. The reset signal is utilized for discharging a stored voltage of the EMI filter.

Abstract: A controller of a power converter includes a sample-and-hold unit and an adjustment unit, wherein the power converter is applied to a Universal Serial Bus power delivery adapter system. The sample-and-hold unit is used for sampling a voltage to generate a sampling voltage during each period of a gate control signal, wherein the sampling voltage corresponds to an output voltage of the power converter. The adjustment unit is coupled to the sample-and-hold unit for adjusting at least one of a frequency of the gate control signal, a current flowing through a primary side of the power converter, and a resistance of a compensation resistor of the controller according to the sampling voltage.

Abstract: A protection circuit applied to an alternating current (AC) power source includes a sample-and-hold unit, a detection unit, and a discharge signal generation unit. The sample-and-hold unit samples a peak value of a direct current (DC) voltage during each period of a corresponding AC voltage, wherein the AC power source provides the AC voltage. The detection unit generates a detection signal when the DC voltage crosses a reference voltage corresponding to the peak value. The discharge signal generation unit generates a count signal when the discharge signal generation unit does not receive the detection signal within a predetermined time of a period of the AC voltage, accumulates the count signal, and generates a discharge signal to a discharge unit when a number of accumulated count signals is greater than a predetermined value, wherein the discharge unit discharges an X capacitor according to the discharge signal.

Abstract: A power controller with over power protection is disclosed, capable of providing a pulse-width-modulation signal to control a power switch. The power controller comprises a pulse width modulator, first and second oscillators, and an over power detector. The pulse width modulator generates the pulse-width-modulation signal. The first oscillator is coupled to the pulse width modulator, for determining a cycle time of the pulse-width-modulation signal. The second oscillator, independent from the first oscillator, determines a maximum over power duration. The over power detector detects the occurrence of an over power event. When the over power event lasts for the maximum over power duration, the pulse-width-modulation signal switches OFF the power switch constantly.

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: 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: Methods and apparatuses for providing a dummy load in a power converter are disclosed. The power converter has a primary winding and a secondary winding isolated from each other. The secondary winding can de-energize to provide an output voltage at an output node for powering a load. The winding voltage at across the secondary winding is sensed to provide a non-switching time, which is checked if it exceeds a predetermined reference time. The output voltage is compared with a predetermined safe voltage. A discharge current is provided as a dummy load to drain from the output node and to lower the output voltage if the on-switching time exceeds the predetermined reference time and the output voltage exceeds the predetermined safe voltage.

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 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.

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: 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.

Abstract: Herein is disclosed a control method suitable for a switching mode power supply. A power switch is controlled according to a clock signal to transfer electrical energy from an input power source to an output power source. A feedback signal is provided in response to an output voltage of the output power source. A clock signal is generated in response to the feedback signal and an input voltage of the input power source. The clock signal has a clock frequency determining a switching frequency of the power switch. When the feedback signal exceeds a relatively-high level, the clock frequency increases in response to decrease to the input voltage. When the feedback signal is below a relatively low level, the clock frequency is independent from the input voltage.

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 power controller with over power protection is disclosed, capable of providing a pulse-width-modulation signal to control a power switch. The power controller comprises a pulse width modulator, first and second oscillators, and an over power detector. The pulse width modulator generates the pulse-width-modulation signal. The first oscillator is coupled to the pulse width modulator, for determining a cycle time of the pulse-width-modulation signal. The second oscillator, independent from the first oscillator, determines a maximum over power duration. The over power detector detects the occurrence of an over power event. When the over power event lasts for the maximum over power duration, the pulse-width-modulation signal switches OFF the power switch constantly.