Patent ID: 7796410
Filing Date: 2010-09-14
Classification: B60L,H02J,H02M,Y02T

Abstract:
1. A switching power supply unit, comprising: a transformer including a first transformer coil, a second transformer coil, and a third transformer coil, the transformer coils being magnetically coupled with one another, a first switching circuit disposed between the first transformer coil and a first DC power supply, and configured to include bidirectional switches, a rectifier circuit disposed between the second transformer coil and a second DC power supply, a second switching circuit disposed between the third transformer coil and AC voltage input terminals, and a switching control section performing control such that when the first DC power supply is assigned higher priority in charging based on a AC input voltage inputted from the AC voltage input terminals, a switching duty ratio in the second switching circuit is set to be fixed, and a switching duty ratio in the first switching circuit is set to be variable, and when the second DC power supply is assigned higher priority in charging based on the AC input voltage, the switching duty ratio in the second switching circuit is set to be variable, and the first switching circuit performs switching operation.