Step-down DC-to-DC converter

摘要

An inductor L2 is inserted in series between an input power supply E and a switching device Q1. An input smoothing capacitor C2 is provided between a connecting point of the inductor L2 and the switching device Q1 and a ground point. Herein, let L2 be an inductance value of the inductor, C2 be an electrostatic capacity of the input smoothing capacitor, and T1 be a time since the switching device Q1 is switched from an ON state to an OFF state until the switching device Q1 is switched to an ON state again according to an output signal from a drive circuit DR, then T1 is set so as to satisfy
0By lowering a voltage applied to a switching device when the switching device switches OFF from ON, it becomes possible to use a switching device having low breakdown voltage in a step-down DC-to-DC converter.

主权项

1. A step-down DC-to-DC converter, comprising:
a switching device and a free wheel semiconductor device sequentially connected in series to an input power supply; a reactor connected sequentially in series between a connecting point of the switching device and the free wheel semiconductor device and a ground point; an output smoothing capacitor; a drive circuit connected directly to the switching device and controlling the switching device to switch ON and OFF; an inductor inserted in series between the input power supply and the switching device; and an input smoothing capacitor provided between a connecting point of the inductor and the switching device and a ground point, wherein when L is an inductance value of the inductor, C is an electrostatic capacity of the input smoothing capacitor, and T1 is a time beginning when the switching device is switched from an OFF state to an ON state and continuing until the switching device is switched to an OFF state again according to an output signal from the drive circuit, then T1 is set so as to satisfy
0