US Patent 7414330 Power switch device

A power switching device which is used to receive plenty of input voltage and output a switch voltage is provided. The device comprises a first switching unit, a second switching unit, and a self-bias unit. The power switching device outputs a switch voltage according to the outputs of the first switching unit and the second switching unit. The self-bias unit outputs a reference voltage to the second switching unit. The first switching unit outputs a first input voltage as the switch voltage according to a first enable signal. The second switching unit outputs a second input voltage as the switch voltage according to the reference voltage and a second enable signal.