A power supply device comprises a driver circuit, a transistor switch, and a first transistor. The driver circuit is configured to provide a stable driving signal and a floating driving signal. The transistor switch has a first terminal, a second terminal connected to a first terminal of the driver circuit, and a third terminal connected to a second terminal of the driver circuit, and is configured to prevent a reverse current based on the floating driving signal. The first transistor has a first current electrode connected to the first terminal of the transistor switch, a second current electrode connected to the first voltage reference, and a control electrode connected to the third terminal of the driver circuit, and is configured to activate and deactivate based on the stable driving signal, and further configured to regulate an input voltage to a substantially constant direct current output voltage.