Power supply for lcd display apparatus

A power supply for an LCD display apparatus is provided to improve an optical efficiency of a lamp by reducing generation of a heat of a switching element and increasing an efficiency of a switching operation. A power supply(100) for an LCD display apparatus includes a converter unit(110), an inverter unit(120), a lamp unit(130), a control unit(140), and a selection unit(150). The converter unit switches an AC power according to a switching control signal to convert the AC power to a DC power. The inverter unit switches the DC power from the converter unit to convert the DC power to a previously set AC power. The lamp unit receives the AC power from the inverter unit and emits light. The control unit generates a first switching control signal(Veao1) by combining a current detection signal(Vs1) detected from the lamp unit with a digital dimming signal(Vd), and generates a second switching control signal(Veao2) according to a voltage detection signal detected from an output terminal of the converter unit. The selection unit selects a signal having the higher voltage level between the first and the second switching control signals to transfer the selected switching control signal.