Patent ID: 6914419
Filing Date: 2005-07-05
Classification: H02M,Y02B

Abstract:
1. A power supply system for outputting a voltage to a load by changing power sources, the power supply system comprising: a DC-DC converter having a first switching element that transfers input voltage to the load, a second switching element that connects the load to a ground, and a control circuit that turns ON and OFF the first switching element and the second switching element with a first selection signal without overlapping ON-periods of the first switching element and the second switching element, wherein the second switching element turns ON m times in a stepping period during which the first switching element turns ON n times, wherein n is a predetermined integer, and m is an integer between any of zero and n that increases in the every stepping period; and a series regulator that outputs a voltage to the load stepping-down the input voltage with a second selection signal.