Patent ID: 7755298
Filing Date: 2010-07-13
Classification: H02M

Abstract:
1. A power supply circuit for a liquid crystal display (LCD), the power supply circuit comprising: a first input port for receiving a turn-on signal and a turn-off signal, the turn-on signal being used to control the power supply circuit to output driving voltages to the LCD, the turn-off signal being used to control the power supply circuit to stop outputting the driving voltages to the LCD; a scaler directly connected to the first input port to receive the turn-on signal and the turn-off signal, the scaler outputting a low voltage when receiving the turn-on signal and outputting a high voltage when receiving the turn-off signal, the scaler comprising an output port; a capacitor; and a pulse width modulation circuit comprising a second input port, the second input port being grounded via the capacitor; and a field-effect transistor, the field-effect transistor comprising a gate electrode connected to the output port of the scaler, a source electrode being grounded, and a drain electrode connected to the second input port of the pulse width modulation circuit, the field-effect transistor being a voltage-controlled field-effect transistor.