An embodiment converter includes a magnetic material, a first circuit including a first winding surrounding the magnetic material and a clamp circuit configured to reset a power conversion operation, the first circuit being configured to convert power received from a first input voltage source to provide the converted power to a load, and a second circuit including a second winding surrounding the magnetic material, the second circuit being configured to convert power received from a second input voltage source to provide the converted power to the load and to perform the power conversion operation being reset by the clamp circuit.

Circuitry for reducing the energy losses of a snubber circuit used to protect current switching devices from overvoltage, comprising a switching cell consisting of a switch with alternating opposite conduction states, the switch being serially connected via one contact to a first diode, the switch includes an inherent output capacitance, the switch connects, via a first stray inductance), between one port of a power supply and an output inductor feeding a load, and the first diode connects, via a second stray inductance, between the other port of the power supply and the output inductor, such that whenever the switch passes from a conducting state to a non-conducting state, its inherent output capacitance is charged by a current pulse from the first stray inductance; a snubber circuit consisting of a ferrite bead, a snubber capacitor and a second diode, the snubber circuit being connecting between the other contact of the switch and the other port, for discharging at least a portion of the charge across the inherent output capacitance of the switch to the snubber capacitor via the other port.

If the capacitance of a snubber capacitor, the inductance of a coil and the magnitude of a resistor are specified such that the resonance frequency of the snubber circuit coincides with the ringing frequency of the transistor, and the impedance of the first loop at the resonance frequency becomes smaller than the impedance of the second loop at the resonance frequency, a current component due to ringing flows in the snubber circuit, and energy is consumed by the resistor. Therefore, it is possible to quickly converge ringing.

A power semiconductor module includes at least one upper arm provided between a positive electrode line and a node and including a power semiconductor device and a freewheeling diode connected in parallel, at least one lower arm provided between a negative electrode line and the node and including a power semiconductor device and a freewheeling diode connected in parallel, and a snubber circuit provided between the positive electrode line and the negative electrode line. The snubber circuit includes a snubber capacitor and a snubber resistor connected in series. At least one control terminal outputs a voltage representing the temperature of the snubber resistor or a voltage related to the temperature of the snubber resistor to a driver that drives the power semiconductor device.

A power converter includes a converter circuit, an inverter circuit, a clamp circuit, a scrubber circuit, and an element including a resistive component. The converter circuit generates from an AC voltage source a DC voltage with AC components superimposed. The inverter circuit has an input connected with an output of the converter circuit. The inverter circuit is configured to convert the DC voltage into an AC voltage by switching, and output the AC voltage to an inductive load. The clamp circuit includes a first capacitor and a first diode connected in series. The clamp circuit is connected between a positive output and a negative output of the converter circuit. The snubber circuit includes a second capacitor and a second diode connected in series. The snubber circuit is connected between the positive output and the negative output of the converter circuit.

Disclosed are a voltage switching circuit and a power adapter having the same. The voltage switching circuit comprises a first switching circuit having a first terminal receiving a first voltage from a first converter, and a second switching circuit having a first terminal receiving a second voltage from a second converter. Second terminals of the first and second switching circuits are electrically connected to form a switching terminal for outputting an output voltage. When the output voltage is required to be switched from the first voltage to the second voltage, the first switching circuit is controlled to be turned off and then the second switching circuit is controlled to be turned on, and when a voltage at the first terminal of the second switching circuit is higher than a preset voltage, the second converter is shut down or kept off.

An integrated circuit for a power supply circuit that includes a transformer including a primary coil, a secondary coil, and an auxiliary coil, and a transistor controlling a current flowing through the primary coil. The integrated circuit includes a first determination circuit determining a state of the load; a second determination circuit determining whether a current of the secondary coil is in a continuous mode and a discontinuous mode, in which the current of the secondary coil respectively does not reach, and reaches, zero when the transistor is off; an oscillator circuit outputting an oscillator signal; and a switching control circuit controlling switching of the transistor in response to a determination result of the second determination circuit and the oscillator signal, and in response to the oscillator signal irrespective of the determination result of the second determination circuit, respectively when the state of the load is light and heavy.

A flyback converter with indirect estimation of primary-side voltage at the secondary-side. The converter includes a primary voltage sensing circuit coupled to the second winding of the converter and being configured to establish an output voltage when a switch of the converter is in the first state and a first diode of the converter is reversed biased, the output voltage being representative of a voltage across the primary winding.

Disclosed herein is an improved flyback converter that separates the magnetic components of the converter into a transformer and a separate, discrete energy storage inductor. This arrangement can improve the operating efficiency of the converter by reducing the commutation losses as compared to a conventional flyback converter. The magnetic components may be constructed on separate magnetic cores or may be constructed on magnetic cores having at least one common element, thereby allowing for at least partial magnetic flux cancellation in a portion of the core, reducing core losses.

A switching power converter includes: a power stage circuit, including at least one transistor which is configured to operably switch an inductor to convert an input power to an output power; and an active EMI filter circuit, including at least one amplifier, wherein the at least one amplifier is configured to operably sense a noise input signal which is related to a switching noise caused by the switching of the power stage circuit, and amplify the noise input signal to generate a noise canceling signal, wherein the noise canceling signal is injected into an input node of the switching power converter, so as to suppress the switching noise and thus reducing EMI, wherein the input power is provided through the input node to the power stage circuit.