DISPLAY DRIVER

摘要

An LC display driver IC suitable to drive source voltage signals to a liquid crystal display, and including an LCD source driver that can convert video image data into a selected one of N gamma-compensated analog gray-level source voltages corresponding to a respective one of the N gamma-compensated reference voltages, and drive out the selected gamma-compensated source voltage. The LCD display driver includes a gamma reference circuit configured to generate the N gamma-compensated reference voltages based on at least one pre-defined gamma curve that includes N (0 to N−1) gamma-compensated reference voltage values divided into M regions defined by M+1 breakpoint voltages, including a range resistor string having a set of R voltage taps that are substantially uniformly spaced, and M+1 range/region digital-to-analog converters (DACs), where each range/region DAC is coupled to a respective subset M+1 of the R voltage taps of the range resistor string, where at least some of the M+1 subsets of voltage taps overlap, and where each range/region DAC is configured to output a respective breakpoint voltage based on the respective subset of voltage taps, including a breakpoint voltage BP(1) from range/region DAC M=1 and a breakpoint voltage BP(M+1) from a range/region DAC M+1, and including intermediate breakpoint voltages BP(2) to BP(M) from respective intermediate range/region DACs. M+1 range/region buffer amplifiers coupled to respective range/region DACs, and configured to output respective buffered breakpoint voltages BP(1) to BP(M+1). An output circuit can generate the N gamma-compensated reference voltages, and includes a reference resistor string having a set of N reference voltage taps, and including M+1 breakpoint locations coupled to receive respective breakpoint voltages from respective range/region buffer amplifiers, with a first end location coupled to receive the breakpoint voltage BP(1), a second end location coupled to receive the breakpoint voltage BP(M+1), and intermediate breakpoint locations coupled to receive the intermediate breakpoint voltages BP(2) to BP(M), and the N reference voltage taps can be divided into M subsets corresponding to the M regions of the gamma curve, each of the M subsets of reference voltage taps forming a respective voltage divider. N output selector circuits, each coupled to a respective one of the N reference voltage taps, can output a corresponding one of the N gamma-compensated reference voltages based on a respective reference voltage tap and the associated voltage divider.

主权项

1. A circuit suitable to drive source voltage signals to a liquid crystal display (LCD), comprising:
an LCD display driver integrated circuit (IC), including an LCD source driver circuit configured to
convert the video image data into a selected one of N gamma-compensated analog gray-level source voltages corresponding to a respective one of the N gamma-compensated reference voltages, anddrive out the selected gamma-compensated source voltage; the LCD display driver including a gamma reference circuit configured to generate the N gamma-compensated reference voltages based on at least one pre-defined gamma curve that includes N (0 to N−1) gamma-compensated reference voltage values divided into M regions defined by M+1 breakpoint voltages, including
a range resistor string having a set of R voltage taps that are substantially uniformly spaced;M+1 range/region digital-to-analog converters (DACs), wherein
each range/region DAC is coupled to a respective subset M+1 of the R voltage taps of the range resistor string, where at least some of the M+1 subsets of voltage taps overlap, and wherein
each range/region DAC is configured to output a respective breakpoint voltage based on the respective subset of voltage taps, includinga breakpoint voltage BP(1) from range/region DAC M=1 and a breakpoint voltage BP(M+1) from a range/region DAC M+1, and includingintermediate breakpoint voltages BP(2) to BP(M) from respective intermediate range/region DACs;M+1 range/region buffer amplifiers coupled to respective range/region DACs, and configured to output respective buffered breakpoint voltages BP(1) to BP(M+1); andan output circuit configured to generate the N gamma-compensated reference voltages, including
a reference resistor string having a set of N reference voltage taps, and including
M+1 breakpoint locations coupled to receive respective breakpoint voltages from respective range/region buffer amplifiers, with a first end location coupled to receive the breakpoint voltage BP(1), a second end location coupled to receive the breakpoint voltage BP(M+1), and intermediate breakpoint locations coupled to receive the intermediate breakpoint voltages BP(2) to BP(M),such that the N reference voltage taps are divided into M subsets corresponding to the M regions of the gamma curve, each of the M subsets of reference voltage taps forming a respective voltage divider; andN output selector circuits, each coupled to a respective one of the N reference voltage taps, and configured to output a corresponding one of the N gamma-compensated reference voltages based on a respective reference voltage tap and the associated voltage divider.