Patent ID: 8305371
Filing Date: 2012-11-06
Classification: G09G

Abstract:
1. An apparatus for generating a VCOM voltage in a display device, comprising: a first buffer amplifier that is biased with a high rail voltage and a low rail voltage for generating the VCOM voltage; a second buffer amplifier that is configured to generate the high rail voltage at an output node of the second buffer amplifier not coupled to an external capacitor; a charge pump that generates the low rail voltage by charge pumping directly from an external power supply voltage, and wherein the high rail voltage generated by the second buffer amplifier is applied on the charge pump for generating the low rail voltage; a third buffer amplifier having an input with a first input voltage from a first multiplexer applied thereon and having another input coupled to an output of the third buffer amplifier that is also coupled to an input of the first buffer amplifier; and a fourth buffer amplifier having an input with a second input voltage from a second multiplexer applied thereon and having another input coupled to an output of the fourth buffer amplifier that is also coupled to another input of the first buffer amplifier.