Patent ID: 6956554

Claim:
An apparatus for switching output voltage signals, applied to a liquid crystal display (LCD), for selectively outputting either a plurality of gamma voltage output signals or a high voltage output signal and a low voltage output signal, the apparatus comprising: a first switching device set for delivering gamma voltage input signals, wherein the first switching device set includes a plurality of voltage signal input nodes for respectively receiving the gamma voltage input signals; a second switching device set for delivering a high voltage input signal and a low voltage input signal, wherein the second switching device set includes a high voltage signal input node for receiving the high voltage input signal and a low voltage signal input node for receiving the low voltage input signal; a resistor string having a plurality of resistors and coupled to the first switching device set and the second switching device set, for selectively outputting either the gamma voltage output signals according to the gamma voltage input signals or a high voltage output signal according to the high voltage input signal and a low voltage output signal according to the low voltage input signal; and a switch selecting device coupled to the first switching device set and the second switching device set, wherein when the switch selecting device outputs a first signal, the first switching device set will deliver the gamma voltage input signals to the resistor string, and when the switch selecting device outputs a second signal, the second switching device set will deliver the high voltage input signal and the low voltage input signal to the resistor string; wherein the switch selecting device outputs a first signal when the liquid crystal display operates in a normal mode, and a second signal when the liquid crystal display operates in an idle mode or a power saving mode.