An energy recovery snubber circuit for a power converter which includes a flyback transformer driven by a converter switch is disclosed. The snubber circuit includes two capacitors which are connected such that, when the snubber circuit is connected to a primary winding of the flyback transformer, the capacitors are charged in series by current flowing in a first direction in the primary winding when the converted switch is turned OFF, to recover energy stored in the leakage inductance of the transformer, and discharged in parallel to cause current flow in a second direction in the primary winding of the transformer, to thereby transfer the recovered energy to the transformer.

A super-efficient single-stage switching power amplifier is realized by not incorporating a rectification process in its power conversion loop while incorporating a bidirectional active clamping circuit to not only remove or maximally reduce otherwise occurring disruptive ringing and spikes but also convert the energy otherwise associated with the ringing and spikes to return energy that goes back to the DC power supply.

A flyback power converter includes: a power transformer, a primary side control circuit, a secondary side control circuit, and an active clamp snubber including a snubber switch and a control signal generation circuit. The control signal generation circuit controls the snubber switch to be conductive during a soft switching period in an OFF period of a primary side switch within a switching period of the switching signal, whereby the primary side switch achieves soft switching. A starting time point of the soft switching period is determined by a current threshold, so that a secondary side current is not lower than the current threshold at the starting time point, whereby the secondary side control circuit keeps the SR switch conductive at the starting time point. The secondary side control circuit turns OFF the SR switch when the secondary side current is lower than the current threshold.

A circuit for providing dynamic output current sharing using average current mode control for active-reset and self-driven synchronous rectification with pre-bias startup and redundancy capabilities for power converters. The circuit communicates a secondary side feedback signal to a primary side via a bidirectional magnetic communicator that also provides a secondary voltage supply. Pre-bias startup is achieved by detection of the output current direction and controlling the gate signals of synchronous rectifiers. The circuit permits dynamic current sharing via a single-control signal and automatic master converter selection and promotion.

The present disclosure provides a snubber circuit, wherein the snubber circuit is used to an electronic equipment including a pulse signal generator, a driving power source and a load, and the snubber circuit includes a current detection module, a control module and a snubber module. The current detection module is connected to the driving power source and detects the driving current of the driving power source. The control module is connected to the current detection module and the snubber module and adjusts a center frequency of the snubber module according to the driving current detected by the current detection module. The snubber module is connected to an output terminal of the pulse signal generator and filters the noise of the pulse signal. Therefore, the present disclosure may dynamically adjust a center frequency of a filtering, so as to increase a filtering performance and increase an efficiency of suppressing EMI.

Systems and methods for operating improved flyback converters are disclosed, in which leakage energy is returned to the input power source rather than to the output load, while still achieving zero voltage switching (i.e., ZVS) operation. In some embodiments, the improved converters may transfer the energy stored in the leakage inductance to a snubber capacitor(s) at the instant of turning off of the control switch. Further, the improved converter embodiments may also retain the stored energy in the snubber capacitor(s) when the power is being delivered to the load by the secondary circuits. The improved converter embodiments may start the transfer of leakage energy stored in the snubber capacitor(s) to the primary winding once the energy stored in the transformer is delivered to the load. Finally, the improved converter embodiments may intelligently control their active clamp switches such that all leakage inductance energy is returned to the input source.

A switch-mode DC converter configured to generate a converted voltage from an input voltage is provided. The switch-mode DC converter includes an inductor configured to store energy, and a switch coupled with the inductor at a switching node, wherein the switch is configurable to be turned on or off to control the discharging of the energy stored at the inductor to an output node of the converter, wherein the output node is configured to provide the converted voltage. The switch-mode DC converter also includes a circuit configured to control a timing of turning-off of the switch based on a voltage difference between the switch, wherein a measurement of the voltage difference is adjusted based on a voltage at the switching node.

An electronic circuit includes: a rectification circuit that rectifies an AC voltage input from an AC power supply; a power factor correction circuit that includes a first switching element and that shapes a current which is input, by the first switching element being driven, from the AC power supply to the rectification circuit; an auxiliary circuit that reduces switching loss in the first switching element by drawing the current from the rectification circuit before the first switching element is turned off so that the current that flows through the first switching element is reduced; and a control circuit that allows the auxiliary circuit to operate for a certain period in a half cycle of the AC power supply, and that does not allow the auxiliary circuit to operate for the other period, which is other than the certain period, in the half cycle of the AC power supply.

A DC/DC converter has an active energy store, such as an inductance, which can be periodically charged and discharged by one or more semiconductor switches, such as transistors. To avoid voltage overshoot, an RCD element is provided for at least one semiconductor switch, wherein a capacitor and a diode of the RCD element are connected in series, and a resistor of the RCD element can be connected either in parallel with the diode or disconnected from the diode by a switch. The diode of the RCD element is arranged so as to be blocking in the conducting direction of the semiconductor switch.

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.