A method for controlling an active snubber circuit includes measuring a gate voltage at a first transistor and measuring a gate voltage at a second transistor. The method also includes determining whether the first transistor and the second transistor are in the same state based on the gate voltage measured at the first transistor and the gate voltage measured at the second transistor. The method also includes, in response to a determination that the first transistor and the second transistor are in the same state, enabling the active snubber circuit. The method also includes, in response to a determination that the first transistor and the second transistor are not in the same state, disabling the enable signal. The method also includes disabling the active snubber circuit in response to the enable signal being disabled.

A flyback DC-DC converter. The converter having a transformer with a primary and a secondary windings, first and second switches, a capacitor coupled between the second switch and the primary winding, where the second switch is arranged to operate such that a sum of a first and second time periods equals a sum of third and fourth time periods, where the first time period is a delay time period from a time that the first switch is turned off to a time that the second switch is turned on, the second time period is a time period that the second switch is on, the third time period is a resonance time period of a resonator formed by a leakage inductance of the transformer and a capacitance of the capacitor, and the fourth time period is a time period for discharge of the leakage inductance of the transformer into the capacitor.

The present application provides an electric protection circuit, which relates to the field of battery power. The electric protection circuit includes a battery pack, a main positive switch, a load device and a main negative switch connected in series. The main positive switch and/or the main negative switch include at least one semiconductor switch. The main positive switch and/or the main negative switch in the electric protection circuit are connected in parallel to a protection module, which absorbs electric energy across two terminals of the main positive switch and/or the main negative switch when the main positive switch and/or the main negative switch are turned off. The technical solution of the present application can improve the safety of the electric protection circuit.

Presented herein is a circuit path configuration for enhancing overvoltage protection in a switching power supply, the switching power supply comprising a bridge rectifier, a primary side switch, and a controller. The circuit path configuration implements input OVP by availing a clamping voltage indicative of a drain-to-source voltage of the primary side switch. The bridge rectifier provides a rectified voltage to a first node. The primary side switch comprises a drain; and the drain is electrically coupled to the first node via a first circuit path. The first circuit path comprises a first circuit path node between the first node and the drain. The controller comprises a voltage monitor input electrically coupled to the first circuit path node via a second circuit path; and the second circuit path provides a monitor voltage to the voltage monitor input.

Apparatus and methods for supplying DC power to control circuitry of a matrix converter is provided. In certain embodiments, a matrix converter includes an array of switches having AC inputs for receiving a multi-phase AC input voltage and AC outputs for providing a multi-phase AC output voltage to a load, such as an electric motor. The matrix converter further includes control circuitry for opening or closing individual switches of the array, and a clamp circuit connected between the AC inputs and AC outputs of the array and operable to dissipate energy of the load in response to an overvoltage condition, such as an overvoltage condition arising during shutdown. The clamp circuit includes a switched mode power supply operable to generate a DC supply voltage for the control circuitry.

A power semiconductor circuit is provided for clamping the voltage across the circuit when a power semiconductor switch is opened (i.e., turned off). The circuit may include a first surge arrester and a first semiconductor switch coupled in parallel with the power semiconductor switch. The first semiconductor switch is coupled in series with the first surge arrester. A second surge arrester may be coupled to the gate of the first semiconductor switch to control current flow through the first semiconductor switch and the first surge arrester.

An isolated gate driver includes a transformer including primary and secondary windings, a synchronous rectifier connected between the secondary winding and an output terminal of the isolated gate driver, a first switch including a first terminal connected to a supply voltage, a second switch including a first terminal connected to the supply voltage, a first damping resistance connected between a first terminal of the secondary winding and a second terminal of the first switch, a second damping resistance connected between a second terminal of the secondary winding and a second terminal of the second switch, a first inverter including an input connected to the first terminal of the secondary winding and an output connected to a gate terminal of the first switch, and a second inverter including an input connected to the second terminal of the secondary winding and an output connected to a gate terminal of the second switch.

In a power converter, a first electrical path connects between the series resonant circuit and a selected terminal from the high- and low-side input and output terminals of the power converter. An auxiliary diode is provided on one of the series resonant circuit and the first electrical path. An auxiliary switch, when turned on, causes an inductor current to flow through the auxiliary diode to the resonance inductor, thus storing electromagnetic energy into the resonance inductor, and causes the resonance inductor and the capacitance component of the series resonant circuit to resonate with each other. A second electrical path bypasses the auxiliary switch for flow of the inductor current. A discharge unit is provided on the second electrical path. The discharge unit is activated to discharge the electromagnetic energy stored in the resonance inductor via the second electrical path.

One circuit includes first and second primary terminals for connection to first and second power transmission lines and a current transmission path extending between the primary terminals and having current transmission path portions separated by a third primary terminal. A first current transmission path portion includes at least one primary switching element connected in series between the first and third primary terminals, the second current transmission path portion includes an energy conversion block connected between the second and third primary terminals, and the energy conversion block includes at least one primary energy conversion element for removing energy from the power transmission lines. The control circuit further includes a converter limb connected across the second and third primary terminals that includes an auxiliary converter. The control circuit further includes a control unit which controls the auxiliary converter to selectively provide a voltage source.

A dual-path active damper reduces power losses while damping ringing waveforms in resonant circuits. One path clamps the peak value of a node voltage at less than a rated voltage of a protected device while allowing the node voltage to ring and decay naturally. Another path waits for some delay after the peak value is clamped until closing an active switch to draw a reset current through an RC snubber to actively dampen the ringing of the node voltage. The delay and on-time of the active switch are set to reduce or even minimize power losses for damping the ringing waveform within a specified period.