A power conversion device is provided. The power conversion device includes a main transformer circuit, a power switch, an auxiliary transformer, a resonant circuit, and a switch circuit. When the power switch is turned on, the switch circuit is enabled according to energy stored in an output capacitor of the main transformer circuit, so that energy associated with a secondary side of a main transformer is coupled to the resonant circuit via the auxiliary transformer so the resonant circuit obtains coupling energy. When the power switch is turned off, the resonant circuit and a parasitic capacitor of the power switch form a resonant tank coupled to a grounding terminal of a power supply side based on the coupling energy.

A power supply comprises a power converter having a transformer, a low side switch configured to draw current from a supply voltage through a primary winding of the transformer and a high side switch configured to couple the primary winding of the transformer to a snubber capacitor. A controller is configured to control the power converter by generating drive signals that control the opening and closing of the high side switch and the low side switch. The controller is configured to selectively control the high side switch according to various modes of operation depending on operating conditions such as input voltage and load power consumption. The modes of operation can include, for example, a mode in which the high side switch is closed and then opened once during each of the series of switching cycles and a mode of operation in which the high side switch is closed and then opened two times during each of the series of switching cycles.

A single-stage power converter can include a boost segment configured to receive an input DC voltage and a flyback segment configured to generate an output DC voltage. The boost and flyback segments may share common switching devices, including a main switch and an auxiliary switch. The boost segment can further include a boost inductor. The flyback segment can further include a bulk capacitor, a resonant capacitor, a flyback transformer, and an output rectifier. The flyback segment can still further include a resonant inductance in addition to a primary winding of the flyback transformer, which may be a parasitic inductance and/or a discrete inductor. The converter can further include control circuitry configured to vary timing, frequency, and/or duty cycle of the main switch to regulate the output voltage. The converter can still further include a rectifier configured to receive an AC input voltage and produce the DC input voltage.

A ZVS (zero voltage switching) control circuit for controlling a flyback power converter includes: a primary side controller circuit, for generating a switching signal to control a primary side switch; and a secondary side controller circuit, for generating a synchronous rectifier (SR) control signal to control a synchronous rectifier switch. The SR control signal includes an SR-control pulse and a ZVS pulse. The primary side controller circuit determines a trigger timing point of the switching signal according to a first waveform characteristic of a ringing signal, to control the primary side switch to be ON. The secondary side controller circuit determines a trigger timing point of the ZVS pulse according to a second waveform characteristic of the ringing signal, to control the synchronous rectifier switch to be ON for a predetermined ZVS time period, thereby achieving zero voltage switching of the primary side switch.

A power converter including: an output unit outputs a converted voltage; a transformer includes a first primary wiring, second primary wiring, and a secondary wiring; a first switch unit is coupled between first primary wiring and a second node; a delay unit is coupled to a control terminal of first switch unit; a first control unit generates a first control signal according to the converted voltage to control ON/OFF state of the first switch unit via the delay unit; the processing unit, coupled between the input voltage and the first node, receives, stores induced power of first induced voltage and releases the stored energy; and the second control unit generates a second control signal to control ON/OFF state of a second switch unit of processing unit to control receiving or releasing the energy according to the input voltage and induced power of first primary wiring.

In some examples, a circuit includes an input circuit, an output circuit, an auxiliary circuit, and a balancing circuit. The input circuit comprises a primary capacitor coupled to primary windings of a transformer. The output circuit comprises a secondary capacitor coupled to secondary windings of the transformer, wherein the secondary windings are coupled to the primary windings. The auxiliary circuit comprises auxiliary windings coupled to the primary windings. The balancing circuit is coupled to the output circuit, the auxiliary circuit, and the input circuit. The balancing circuit is configured to balance a voltage across the primary capacitor with a voltage across the secondary capacitor.

Electronic circuitry and method of operating the same to shape and reduce the circulating current through the active clamp in a flyback converter and to harvest most of the leakage inductance energy to provide the bias power. Methodologies for minimizing the circulating energy in the clamp circuit in order to improve efficiency of operation of the same. A method for using a portion of the leakage inductance energy in order to create zero voltage switching conditions at the main primary switch.

An active clamp circuit includes an active clamp capacitor coupled in series with an active clamp switch and an active clamp controller circuit to receive an active clamp switch current that passes through the active clamp switch and to control the active clamp switch based on the received active clamp switch current. The active clamp controller circuit is configured to enable the active clamp switch based on a first amplitude comparison, the first amplitude comparison being based on the active clamp switch current. The active clamp controller circuit is configured to disable the active clamp switch based on a second amplitude comparison and a third amplitude comparison, the second amplitude comparison and the third amplitude comparison being based on the active clamp switch current.

The present invention relates to the technical field of high-gain DC-DC converters, and disclosed is a high-gain quasi-resonant DC-DC converter based on a voltage doubling rectifier circuit. On the basis of a half-bridge quasi-resonant high-gain circuit topology and by combining a bidirectional positive and negative voltage doubling rectifier circuit, the present invention provides a high-gain DC-DC converter. The converter can further improve output voltage gain and reduce output voltage ripples, and can improve the system efficiency while reducing the number of turns of a high-frequency transformer; moreover, the converter can achieve soft-switching control, thereby having the advantages of low voltage and current stress, high efficiency, and the like.

Provided is a new LDC to satisfy the recent requirements for a bidirectional large-capacity isolated LDC (DC-DC converter). The present disclosure provides a new bidirectional isolated LDC, in which two converters with different power circuit topologies operate in parallel in order to enable both buck mode and boost mode. The two applied converters are a phase-shift full-bridge converter with full-bridge synchronous rectification and an active-clamp forward converter. According to the present invention, it is possible to achieve the advantages of both a phase-shifted full-bridge converter with full-bridge synchronous rectification applied and an active clamping forward converter. Thus, it is to possible to minimize output voltage and current ripples, thereby improving the quality of the LDC output power while minimizing electromagnetic waves generated while a product is operating.