An active clamp flyback circuit includes: a clamp capacitor that is connected to a primary-side winding of a transformer and that is configured to absorb leakage inductance energy of the primary-side winding; an auxiliary switching transistor that is configured to control the clamp capacitor to perform reverse excitation power charging on the primary-side winding by using the auxiliary switching transistor; a first diode, where the first diode is connected in series between the clamp capacitor and the auxiliary switching transistor; and a second diode, where the second diode is connected between the first diode and the clamp capacitor , and the second diode is connected in series between the clamp capacitor and a primary-side auxiliary winding.

A bridge circuit with series-connected switches and associated control method. The bridge circuit has a first bridge arm and a second bridge arm coupled to a common node, the first bridge arm has a plurality of series-connected first main switches, each first main switch is coupled in parallel with an auxiliary module, each first auxiliary module has a clamping capacitor and an auxiliary switch, the first bridge arm receives a first main switch signal to control the plurality of series-connected first main switches, the second bridge arm receives a second main switch signal, the control method is sensing voltages of the clamping capacitors in the first bridge arm, correspondingly generating voltage sensing signals, and turning on at least one auxiliary switch for a predetermined time during a dead time according to a sorting result of the voltage sensing signals.

A power supply system includes an input stage comprising first and second input switches to provide a primary current responsive first and second input switching signals. A transformer generates a secondary current responsive to the primary current. An output stage comprises an output, a first output switch, a second output switch and a clamping switch. The output stage can be configured to generate an output voltage at the output by rectifying the secondary current responsive to respective first and second output switching signals. The clamping switch can be configured to close responsive to a clamp switching signal during an activation dead-time between closing the first input switch and the second input switch. The system further includes a switching controller configured to generate the first and second input switching signals and the first and second output switching signals based on the output voltage, and to generate the clamp switching signal.

A power converter circuit includes a power stage that includes a transformer and a switch. The switch can be controlled in response to a PWM signal to provide a primary current through a primary winding of the transformer to induce a secondary current in a secondary winding of the transformer to generate an output voltage. The power stage includes a switching node between the switch and the primary winding having a switching voltage. The circuit also includes a switching controller configured to generate the PWM signal in response to a ramp signal. The ramp signal can have an amplitude of a slope that is proportional to a decay rate of a magnetizing current of the transformer and generated in response to feedback from the power stage. The switch can be activated in response to the switching voltage having an amplitude of approximately zero volts based on the amplitude of the ramp signal.

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.

A spike suppression circuit includes a wide bandgap transistor, a first transistor, a clamping circuit, and a capacitor. The wide bandgap transistor is depletion-type. The first transistor is coupled in series with the wide bandgap transistor. The clamping circuit provides a voltage difference, and is coupled to a common node between the wide bandgap transistor and the first transistor. The capacitor provides a supply voltage for the clamping circuit. When the first transistor is turned off, the capacitor can recycle spike energy at the common node.

A clamping circuit includes an energy storage section and a pulse generator to generate a pulse in which the energy storage section stores energy from a main power supply.

A control circuit for a flyback converter is configured to adjust a conduction time of an auxiliary switch of the flyback converter in accordance with a drain-source voltage of a main switch of the flyback converter when the main switch is turned on, in order to achieve zero-voltage switching of the main switch. The flyback converter can include: a main power stage having the main switch to control energy storage and transmission of a transformer; and a clamp circuit having an auxiliary switch to provide a release path for releasing energy of leakage inductance of the transformer.

A method involves receiving, at an active clamp controller circuit, an active clamp switch current that passes through an active clamp switch. The active clamp switch is enabled using the active clamp controller circuit in response to determining, based on the active clamp switch current, body-diode conduction of the active clamp switch. The active clamp switch is disabled using the active clamp controller circuit in response to determining, based on the active clamp switch current, a first zero-crossing of the active clamp switch current and a second zero-crossing of the active clamp switch current.

The invention relates to a direct-current voltage converter (10) for electrical power transmission from a secondary side to a primary side of the direct-current voltage converter (10), which has on the primary side an actively clamped flyback converter circuit having a controlled first switch (1) and a controlled second switch (2), and the primary side is inductively coupled to the secondary side. The current of a secondary coil (6) on the secondary side, for inductive coupling to the primary side, is switched by a single controlled third switch (3) on the secondary side, and the direct-current voltage converter has a regulator (12) which, in parts of a regulating cycle, conductively connects the third switch (3) to the first switch (1).