Patent attributes
A power supply for a computer includes a transformer, a rectifier, a pulse width modulation (PWM) controller, a relay, a power switch, and a battery. The PWM controller includes a voltage terminal and a pulse terminal. The relay includes a switch and an inductance coil. An alternating current (AC) power supply is connected to a primary inductance coil of the transformer via the rectifier. A secondary inductance coil of the transformer provides a standby voltage. A positive voltage terminal of the rectifier is connected to the pulse terminal of the PWM controller via the primary inductance coil of the transformer. The switch is connected between the positive voltage terminal of the rectifier and the voltage terminal of the PWM controller. The inductance coil and the power switch are connected in series between the battery and ground. The power switch is controlled by powering on or off the computer.