Patent ID: 6690591
Filing Date: 2004-02-10
Classification: H02M

Abstract:
A single stage converter in an LCD backlight inverter which includes powering passage alternating means connected between a supply voltage input terminal and a transformer for alternating a power supply passage into the first side of the transformer to allow transformation in the transformer and a plurality of lamps connected to an output terminal of the transformer, the single stage converter comprising:a transformer controller receiving a feedback current from the output terminal of the transformer and flowing through the lamps, comparing the feedback current with a dimming signal and comparing a compared value thereof with a periodically generated triangle wave to control the operation of the powering passage alternating means so as to control the operation of the transformer; shut-down judging means for receiving the feedback current from the output terminal of the transformer flowing through the lamps and comparing the feedback current with a reference voltage to compare the size of the current flowing through the lamps so as to judge whether a shut-down takes place; and a stabilizer receiving a supply voltage inputted through the supply voltage input terminal and comparing the supply voltage with the reference voltage to judge whether the supply voltage is in an overvoltage state, and if judging means judges that the shut-down occurs, providing a judgment signal into the transformer controlling means to adaptively correspond to the shut-down or the overvoltage state; wherein the shut-down judging means and the stabilizer are connected in series, and generally connected in parallel between the supply voltage input terminal and a feedback current input terminal.