| 摘要 |
A power supply circuit includes a first DC-DC converter, a second DC-DC converter, a voltage detection circuit, a delay circuit and a switch. The second DC-DC converter converts an output voltage of the first DC-DC converter into a second voltage and outputs the second voltage. The voltage detection circuit outputs a detection signal when an output voltage of the first DC-DC converter becomes a threshold voltage or more. The delay circuit outputs 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. The switch is connected between the first DC-DC converter and an output terminal. The second DC-DC converter starts an operation in response to the delayed detection signal outputted from the delay circuit. The switch is closed in response to an output from the second DC-DC converter. |
