Abstract: A flyback power converter includes: a transformer, a primary side switch, a snubber capacitor and an active clamp snubber. The snubber capacitor is charged by a leakage inductance current of a primary winding fora snubber period following after a time point when the primary side switch is turned OFF. The active clamp snubber includes a snubber control switch which is connected in series to the snubber capacitor. The series circuit of the snubber control switch and the snubber capacitor is connected in parallel to the primary winding. The leakage inductance current charges the snubber capacitor through the snubber control switch during the snubber period. The snubber capacitor provides a capacitor voltage as electrical power of the active clamp snubber. A voltage level of a reference node between the snubber control switch and the snubber capacitor serves as a snubber ground level of the active clamp snubber.

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 and an over power protection method thereof are provided. A number of times a sensing voltage exceeding a reference voltage is counted, so as to determine whether to disable a power switch in the power conversion apparatus according to the number of times the sensing voltage exceeding the reference voltage, in which the sensing voltage corresponds to a current flowing through the power switch on a resistor.

Abstract: A power conversion apparatus and an over power protection method thereof are provided. A number of times a detection voltage being greater than a first reference voltage and a number of times the detection voltage being greater than a second reference voltage are counted, so as to obtain a first count value and a second count value, in which the detection voltage is a voltage on a resistor in response to a current flowing through a power switch. Stop switching the power switch when the first count value is greater than or equal to a first threshold value or when the second count value is greater than or equal to a second threshold value.

Abstract: A power supply apparatus is provided. The power supply apparatus includes a power conversion circuit, an AC safety capacitor and a control unit. An AC input voltage is received by an input side of the power converting circuit, and is converted to a DC output voltage. The AC safety capacitor is connected across the input side. The control unit controls the operation of the power converting circuit, where the control unit samples and holds a voltage between two terminals of the AC safety capacitor to obtain a holding voltage, and compares the holding voltage and the AC input voltage during each period of a clock signal, so as to decide to discharge electric energy stored by the AC safety capacitor according to a comparison result.

Abstract: A power conversion apparatus and an over power protection method thereof are provided. A number of times a detection voltage being greater than a first reference voltage and a number of times the detection voltage being greater than a second reference voltage are counted, so as to obtain a first count value and a second count value, in which the detection voltage is a voltage on a resistor in response to a current flowing through a power switch. Stop switching the power switch when the first count value is greater than or equal to a first threshold value or when the second count value is greater than or equal to a second threshold value.

Abstract: A power conversion apparatus and an over power protection method thereof are provided. A number of times a sensing voltage exceeding a reference voltage is counted, so as to determine whether to disable a power switch in the power conversion apparatus according to the number of times the sensing voltage exceeding the reference voltage, in which the sensing voltage corresponds to a current flowing through the power switch on a resistor.

Abstract: A power supply apparatus is provided. The power supply apparatus includes a power conversion circuit, an AC safety capacitor and a control unit. An AC input voltage is received by an input side of the power converting circuit, and is converted to a DC output voltage. The AC safety capacitor is connected across the input side. The control unit controls the operation of the power converting circuit, where the control unit samples and holds a voltage between two terminals of the AC safety capacitor to obtain a holding voltage, and compares the holding voltage and the AC input voltage during each period of a clock signal, so as to decide to discharge electric energy stored by the AC safety capacitor according to a comparison result.

Abstract: Disclosed is a power converter control circuit, comprising at least a power converter circuit and a control circuit. The power converter circuit is able to boost up an input voltage into a greater driving voltage and supply it to the driven device. Moreover, the power converter circuit is also able to generate a voltage signal and a current-sense signal separately, and then combine them into a joint voltage/current-sense signal. The control circuit receives the joint voltage/current-sense signal and resolves it into an over-voltage signal and a current-sense signal with the aid of a modulation signal. The two signals are separately fed into an over-voltage protection device and an over-current protection device for comparison; the outcomes are utilized to execute the over-voltage protection and the over-current protection.

Abstract: A charger circuit comprising: a charging path coupled between an input voltage and a battery; a power switch on the charging path; a switch control circuit controlling the power switch; a timer counting a charging period; and a low current control circuit issuing a signal to the switch control circuit to control the power switch such that a charging current is maintained to be a predetermined low current when the timer counts to a predetermined maximum charging period.

Abstract: The present invention discloses a single-wire transmission interface, and a method of transmission through single-wire. The method comprises: providing a single-wire signal through a single-wire; and transmitting information only in a transmission period defined by a fixed first time period starting from one of a rising or a falling edge of the single-wire signal.

Abstract: A light emitting diode (LED) driving apparatus is provided, and which includes a first operational amplifier (OPA) having a positive input terminal receiving a predetermined voltage related to a current flowing through an LED string; a first resistor having a first end coupled to a negative input terminal of the first OPA and a second end coupled to a ground; a power transistor having a gate coupled to an output of the first OPA, a drain coupled to a cathode of the LED string and a source coupled to the first end of the first resistor; an error amplifier having a first input terminal coupled to the gate of the power transistor, a second input terminal receiving a reference voltage and an output terminal outputting a control voltage; and a power conversion stage providing a DC voltage to an anode of the LED string according to the outputted control voltage.

Abstract: Disclosed is a power converter control circuit, comprising at least a power converter circuit and a control circuit. The power converter circuit is able to boost up an input voltage into a greater driving voltage and supply it to the driven device. Moreover, the power converter circuit is also able to generate a voltage signal and a current-sense signal separately, and then combine them into a joint voltage/current-sense signal. The control circuit receives the joint voltage/current-sense signal and resolves it into an over-voltage signal and a current-sense signal with the aid of a modulation signal. The two signals are separately fed into an over-voltage protection device and an over-current protection device for comparison; the outcomes are utilized to execute the over-voltage protection and the over-current protection.

Abstract: A charger for a portable device includes a USB detector connected to a data pin to detect the effective resistance on the data pin before a USB transceiver is enabled, to identify USB or adapter plug in and control a charging current for a battery accordingly.

Abstract: A charger for a portable device includes a USB detector connected to a data pin to detect the effective resistance on the data pin before a USB transceiver is enabled, to identify USB or adapter plug in and control a charging current for a battery accordingly.

Abstract: Methods are proposed for a buck boost voltage regulator to monitor the output voltage or both the inductor current and the output voltage of the buck boost voltage regulator to control the buck boost voltage regulator to reduce the switching times of the power switches of the buck boost voltage regulator to improve the light load efficiency of the buck boost voltage regulator.

Abstract: A charger for a portable device includes a USB detector connected to a data pin to detect the effective resistance on the data pin before a USB transceiver is enabled, to identify USB or adapter plug in and control a charging current for a battery accordingly.

Abstract: For output current detection of a voltage regulator, a sensing circuit is coupled to a high-side element of the regulator and detects the current therein to generate a sensing current. A simulation circuit is coupled to the sensing circuit and generates a summed current by simulation with the sensing current. A setting resistor is coupled to the simulation circuit and receives the summed current to provide an output for feedback control of the voltage regulator.

Abstract: A charging circuit with an application system thereof provides an error amplifier to control a transistor switch for controlling the charging power source to charges the battery. When the voltage difference between the power source and load terminals of the transistor switch drops along with the transistor switch being turned on, the output voltage of the error amplifier changes as well to increase the turning-on resistance of the transistor switch such that the voltage difference between the power source and load terminals is capable of maintaining at a value above a certain reference level for avoiding the unstable state resulting from the charging circuit being turned on and off frequently.