Patent ID: 7557467
Filing Date: 2009-07-07
Classification: H02J,H02M

Abstract:
1. A portable photographing apparatus having at least a first power supply terminal and a second power supply terminal, the first power supply terminal being connected to an AC adaptor, the second power supply terminal being connected to a battery, the apparatus comprising: generating means for generating a reference voltage with at least one of voltages supplied from the first power supply terminal and the second power supply terminal; comparing means for comparing an input voltage supplied from the first power supply terminal with the reference voltage; dividing means for dividing the input voltage of the first power supply terminal and the input voltage of the second power supply terminal and outputting divided voltages; controlling means for controlling the portable photographing apparatus; a first switching device connected to the first power supply terminal, wherein the first switching device comprises an FET and a mechanical portion comprising two face-to-face connected FETs and a resistor; and a second switching device connected to the second power supply terminal, wherein the second switching device comprises an FET and a mechanical portion comprising two face-to-face connected FETs and a resistor, wherein when the input voltage and the reference voltage have been compared by the comparing means, if the input voltage is higher than the reference voltage, the first switching device is turned on and the second switching device is turned off, and if the input voltage is lower than the reference voltage, the first switching device is turned off and the second switching device is turned on, wherein the controlling means receives the divided voltages directly from the dividing means and the reference voltage directly from the generating means without being affected by the first switching means and the second switching means, and wherein when the first power supply terminal is disconnected from the AC adaptor, the first switching device is unconditionally turned off for a predetermined period.