A switching power supply circuit with synchronous rectification has an energy storage component, a SR switch coupled to a secondary side of the energy storage component, and a secondary control circuit. The secondary control circuit has a turning-ON control circuit for providing a turning-ON control signal based on a comparison of a drain to source sensing voltage of the SR switch and a turn ON threshold, a mode determination circuit for providing a mode signal to determine a turn ON delay based on a detection to a transient event or the drain to source sensing voltage ringing of the SR switch, and a gate driver circuit for driving the SR switch. When the turning-ON control signal is asserted, the gate driver circuit charges a gate voltage of the SR switch after the turn ON delay based on the mode signal, to turn ON the SR switch.

In a half-bridge circuit, in a case that a first transistor element is turned ON, a primary winding current flows from a power supply to a primary winding. Then, in a case that the first transistor element is turned OFF, (i) a first rectifying element current flows from a secondary winding to a first rectifying element, or (ii) a second rectifying element current flows from a tertiary winding to a second rectifying element.

The present disclosure provides a forward converter with secondary LCD connected in parallel to realize forward and backward energy transmission, comprising a forward converter main circuit and an energy transfer and transmission circuit. The forward converter main circuit includes a high-frequency transformer T, a switching tube S, a diode D1, a diode D2, an inductance L1, and a capacitor C1. The energy transfer and transmission circuit includes a diode D3, a capacitor C2 and an inductance L2.

The present disclosure provides a forward converter with secondary LCD connected in series to realize excitation energy transfer, comprising a forward converter main circuit and an energy transfer and transmission circuit. The forward converter main circuit includes a high-frequency transformer T, a switching tube S, a diode D1, a diode D2, an inductance L1, and a capacitor C1. The energy transfer and transmission circuit includes a diode D3, a capacitor C2, and an inductance L2. The circuit structure of the present disclosure has simple circuit structure and high reliability. And the reverse recovery problem of the diode could be eliminated by the soft switch-off or soft switch-on of the switching tube, which further reducing the loss of switching tube and diodes and improving the overall efficiency. In addition, the excitation energy could be transferred to the load side to improve the energy transmission efficiency.

A drive device includes a driver configured to drive a high-side transistor and a low-side transistor; a first current detecting part for detecting one of an upper-side current that flows to the high-side transistor and a lower-side current that flows to the low-side transistor; a first current determining part that detects a sign of switching of a forward direction/reverse direction of the upper-side current or the lower-side current detected by the first current detecting part or the switching per se; and a slew rate adjusting part configured to control the driver such that a slew rate of the high-side transistor or the low-side transistor is adjusted according to a determination result of the first current determining part.

The semiconductor device includes: a transistor, and a body diode included in the transistor so that the body diode is anti-parallel to the transistor, and a diode anti-parallel connected to the bidirectional current-conduction device, wherein the bidirectional current-conduction device allows a first current and a second current to flow, and allows at least the second current to switch between conduction and non-conduction, the first current flowing in a first direction from a first main electrode of the transistor to a second main electrode facing the first main electrode, the second current flowing through the body diode in a second direction opposite to the first direction, and the diode is smaller in area than the bidirectional current-conduction device in a plan view.

A switching element 1 has a gate terminal connected to a Vout end 123 of a driving circuit 12 via a capacitor 11 and a resistor 13 connected in parallel. The switching element 1 has a source terminal connected to a Vee end 124 of the driving circuit 12 via a capacitor 14 and a resistor 14 connected in parallel.

The present application provides a power conversion device such that input current and output current can be accurately estimated without providing a special circuit. A DC-DC converter including a control unit and semiconductor switching elements is such that a current detecting current transformer is connected in series between a high voltage battery and the semiconductor switching elements, in addition to which the DC-DC converter includes a current-to-voltage conversion circuit on a secondary side of the current transformer, and the control unit estimates an input current from an AD conversion value input from the current-to-voltage conversion circuit.

The present disclosure, in an aspect thereof, has an object to effectively reduce transient current in a rectifier circuit. In a rectifier circuit, a current flows from a power supply to a coil when a transistor is turned on. Then, when the transistor is turned off, a second rectifier current flows from the coil to a second rectifier.

Provided is a technique for reducing the size and cost of a semiconductor device. A semiconductor device includes an IGBT module having an IGBT, and a MOSFET module having a MOSFET whose operational property is different from that of the IGBT, the MOSFET module being connected to the IGBT module in parallel. The semiconductor device is capable of selectively executing an operation mode in which switching timing in the IGBT module and switching timing in the MOSFET module are non-identical.