DC-to-DC converter

摘要

A zero-voltage-switching d.c.-to-d.c. converter includes a transformer (T) having a primary winding (N1) connected across a d.c. power supply (Ei) via a parallel connection of a first switch (Q1) and a capacitor (C1), and a secondary winding (N2) connected across a load (Ro) via a rectifying and smoothing circuit (3). In order for the switch to be turned on and off at zero voltage, there is provided, in parallel with the serial circuit of the transformer primary and the switch, a serial circuit of a tertiary winding (N3) and quaternary winding (N4) of the transformer (T), a resonant inductor (L1), a first diode (D3), and a second switch (Q2). A second diode (D4) is connected in parallel with the serial connection of the transformer quaternary, resonant inductor, first diode, and second switch. A switch control circuit (4 or 4a) is connected between the rectifying and smoothing circuit and the first and second switches for on-off control of the latter in prescribed time relationship to each other according to the converter output voltage.