Patent ID: 6038149
Filing Date: 2000-03-14
Classification: H02M,H05B,Y02B

Abstract:
A power supply device including:a rectifying means for rectifying alternating current from an AC power supply;a first capacitor connected in parallel with an output terminal of said rectifying means;a diode connected in series in the normal polarity with an end of said first capacitor;a second capacitor connected in parallel with said first capacitor through said diode;a partially smoothed circuit which includes an inductance element and a charge capacitor and is connected in parallel with said second capacitor, the second capacitor adapted to charge said charge capacitor at a voltage lower than the maximum instantaneous voltage output from the rectifying means;an inverter circuit which includes a parallel resonance circuit, a switching element and a second resonance capacitor;said inverter circuit being connected in parallel with said partially smoothed circuit;said parallel resonance circuit having a first resonance capacitor and a resonance inductor;said switching element being connected in series with said parallel resonance circuit;said second resonance capacitor being connected in parallel with said switching element;said inverter circuit being of a type effective to generate high frequency voltage by means of switching actions of said switching elements;said charge capacitor having a charge voltage;said first capacitor supplies current to said resonance inductor when said switching element is active and said output terminal of said rectifying means is at a higher voltage than said charge voltage;said second capacitor supplies current to said resonance inductor when said switching element is active and said output terminal of said rectifying means is at a lower voltage than said charge voltage;said second capacitor is charged by a first and second resonance condition when said switching element is not active;said first resonance condition is at least formed between said second capacitor and said resonance inductor; andsaid second resonance condition is at least formed between said second resonance capacitor and said resonance inductor.