Patent ID: 7199642
Filing Date: 2007-04-03
Classification: H02J,H02M

Abstract:
1. A source-voltage-operated circuit comprising: an operated circuit section operated according to a voltage supplied by a battery, said operated circuit section having: a series circuit of a coil and a first switching device, and a light-emitting diode connected parallel to said coil, wherein when said first switching device is turned on, a current flows from said battery through said coil and said first switching device, and when said first switching device is turned off, a loop current flows through said coil and said light-emitting diode; a control-voltage-supplying circuit section having a second switching device and a capacitor, said second switching device connected to a connection point of said coil and said first switching device for controlling a direction of a current from said coil to said capacitor, and said capacitor storing a portion of energy from said switching operation of said first switching device and outputting the resultant voltage as an operating voltage, the resultant voltage being higher than the voltage supplied by said battery; and a control circuit section operated according to the operating voltage for controlling the operation of said operated circuit section and stopping the operation of said operated circuit section when the operating voltage is decreased below a given reset voltage.