| 摘要 |
PURPOSE:To increase a power factor of an AC/DC converter which receives a commercial AC power supply and generates a DC output. CONSTITUTION:In an AC/DC converter wherein a main circuit is constructed of a rectifier circuit RC1, a field-effect transistor Q1, a transformer Tr1 and a rectifier circuit RC2, a choke coil L1 and a diode D1 are inserted between the rectifier circuit RC1 and a smoothing capacitor C1, and a capacitor C3 and a parallel circuit of a choke coil L3 and a capacitor C4 are connected between the node of the choke coil L1 and the diode D1 and the node of the field-effect transistor Q1 and a primary winding n1. A time ratio control for stabilizing an output and a phase control for preventing an excess of a charging voltage of the capacitor C1 are applied to a control circuit U1 executing a control to drive the field-effect transistor Q1, so as to improve further an input power factor. |
