An exemplary power supply circuit includes an output terminal configured for providing electric power to a load circuit, a direct current (DC) power supply, a first resistor, a second resistor, a first switch and a second switch. The first switch includes a control electrode is grounded via the first resistor, a first current conducting electrode is connected to the DC power supply, and a second current conducting electrode is connected to the output terminal. The second switch includes a control electrode is connected to the output terminal, a first current conducting electrode is connected to the DC power supply, and a second current conducting electrode is connected to the control electrode of the first switch. The second resistor is interconnected the first current conducting electrode of the first switch and the second current conducting electrode of the first switch.