POWER SUPPLY

摘要

PROBLEM TO BE SOLVED: To prevent the voltage across a smoothing capacitor from increasing excessively under no-load or light load state. SOLUTION: A series circuit of a diode Di and a smoothing capacitor Cdc is connected between the DC output terminals of a rectifier DB. An inverter circuit INV is supplied with power from the smoothing capacitor Cdc and a bridge circuit comprising four impedance elements Z1-Z4 is connected to the output side of the inverter circuit INV. One impedance element Z2 is connected with a load L and the primary winding n1 of a feedback transformer TF is connected between the output side of the bridge circuit. Secondary winding n2 of the feedback transformer TF is connected in series with a capacitor Cin and the series circuit of the secondary winding n2 and the capacitor Cin is connected between the DC output terminals of the rectifier DB. Consequently, the power being fed back through the transformer TF to the smoothing capacitor Cdc is increased as power supply to the load L increases.