A 10-bit Resistor-Floating-Resistor-String DAC (RFR-DAC) for High Color-Depth LCD Driver ICs

Abstract

This work proposes a novel resistor-floating-resistor-string digital-to-analog converter (RFR-DAC) architecture with a 10-bit resolution for liquid crystal display (LCD) driver applications. The proposed architecture improves the linearity of DAC, unifies its channel performance, and achieves a 10-bit resolution with a compact die size smaller than those of the state-of-the-art 10-bit DACs. The proposed RFR-DAC combines a 6-bit RDAC and a 4-bit FR-DAC (floating-resistor-string DAC) to offer unique two-voltage-selection and one-voltage-selection schemes without the need of unity-gain buffers to isolate parallel-connected resistor strings. A stacked floating class-AB control is also devised to bias the last output buffer stage. The 10-bit RFR-DAC prototypes are implemented using 0.35-μm/0.5-μm CMOS technology with the worst DNL/INL = 0.11/0.92 LSB via a two-voltage-selection scheme; and 1.37/1.45 LSB via a one-voltage-selection scheme.