Patent ID: 8188618
Filing Date: 2012-05-29
Classification: H02J,H02M

Abstract:
1. A power supply circuit comprising: a first DC-DC converter which is configured to convert a voltage supplied from a power supply to a first voltage and is configured to output the first voltage therefrom; a voltage detection circuit which is configured to output a detection signal when an output voltage of the first DC-DC converter becomes a threshold voltage or more; a delay circuit which is configured to output a delayed detection signal with a delay of a predetermined time from a point of time that the detection signal outputted from the voltage detection circuit is inputted to the delay circuit; a switch which is connected between the first DC-DC converter and an output terminal and is configured to output the output voltage of the first DC-DC converter to the output terminal when the switch is closed; and a second DC-DC converter which is configured to convert the output voltage of the first DC-DC converter into a second voltage and to output the second voltage therefrom, wherein the second DC-DC converter is configured to start an operation thereof in response to the delayed detection signal outputted from the delay circuit, and the switch is closed in response to an output from the second DC-DC converter.