Patent ID: 7133650

Claim:
A power supply having a stable reset function in a mobile electronic unit comprising a digital signal processing unit for processing a video signal or an audio signal input into the mobile electronic unit, the power supply comprising: a power supply unit, which generates a plurality of source voltages needed in respective elements of the mobile electronic unit using an input power source supplied from an adapter or battery; a first reset unit, which, when at least one output voltage from the power supply unit is abnormal, generates a first reset signal; a second reset unit, which, when the input power source from the adapter or battery is less than a predetermined reference voltage, generates a second reset signal, the second reset unit comprising: a first transistor, wherein power is supplied by the adapter or battery being applied to a base terminal of the first transistor and the source voltage for the digital signal processing unit being applied to an emitter terminal of the first transistor, and a second transistor, which is connected to a collector terminal of the first transistor and generates the second reset signal depending on whether the first transistor is turned on; and a controller which is reset by means of one of the first and second reset signals, and when the second reset signal is applied thereto, controls the power supply unit to cut off the source voltage for the digital signal processing unit.