Patent ID: 7872376

Claim:
A multi-input power-switching circuit, which acquires more than one input power and selects one said input power to connect with a power conversion unit, comprising: more than one power input terminal respectively receiving said input powers, wherein a switch is arranged in each path via which one of said input powers is transferred from said power input terminal to said power conversion unit; more than one detection/evaluation circuit each including: a voltage division/separation unit, a filter/rectifier unit connected to said voltage division/separation unit in series, and an amplifier unit connected to said filter/rectifier unit in series, wherein said voltage division/separation unit is connected to said path to receive a partial voltage signal from one of said input powers and outputs said partial voltage signal to said filter/rectifier unit; said partial voltage signal is processed by said filter/rectifier unit, and then said amplifier unit generates a detection signal according to said partial voltage signal; and a switching/controlling unit connected to an output of each of said amplifier units to receive said detection signal from each of said detection/evaluation circuits, determining which of said power input terminals has a higher voltage level according to said detection signals, generating a turn-on signal to turn on said switch connected with said power input terminal having a higher voltage level; wherein said multi-input power-switching circuit and said power conversion unit are separately accommodated in two casings, said casing accommodating said multi-input power-switching circuit has more than one said power input terminal; said casing accommodating said multi-input power-switching circuit and said casing accommodating said power conversion unit respectively have connection terminals, which can be selectively electrically connected to each other, so that if separated, the power conversion unit can receive an put power from its connection terminal to function as a general power supply device.