A power supply of a video and audio system is coupled to a first switch and a second switch. A power management unit is coupled between the first switch and at least one electronic device. An integrated circuit includes a first circuit and a second circuit. The first circuit is coupled to the power management unit and the at least one electronic device for controlling the operation of the at least one electronic device. The second circuit is coupled to a battery, the first switch, the second switch, and the first circuit for controlling the first switch and the second switch.