POWER SAVING POWER SUPPLY DEVICE

摘要

PROBLEM TO BE SOLVED: To prevent degradation of efficiency around 45°which is the most desirable area as the compromise point with the noise and the efficiency when an intermediate current value is passed through a load in an electrical unit or a power circuit. SOLUTION: This power-saving power supply unit comprises commercial power; a transformer including at least a primary winding and a secondary winding; a first rectification circuit for rectifying the output of the secondary winding of the transformer; a two-way switching circuit for switching the current flowing from the commercial power to the primary winding of the transformer; and a control circuit in which the on-time of the switching circuit is one period or an integer multiple of a voltage waveform of the commercial power, and which controls the turning on/off of the switching circuit at the timing of the phase difference substantially equal to the voltage waveform of the commercial power. A second rectification circuit arranged via the commercial power to an impedance circuit supplies the power supply to the control circuit. The impedance circuit is substantially resistance in the frequency of the commercial power. COPYRIGHT: (C)2005,JPO&NCIPI