Patent ID: 7973748

Claim:
A data driver for an OLED display, comprising: a resistor string for providing a set of gamma voltages; a plurality of digital-to-analog converters, each digital-to-analog converter for converting an input word into an output voltage selected from the gamma voltages; a plurality of converting transistors, each converting transistor for conducting a driving current and having a gate-to-source voltage determined by the output voltage from one of the plurality of digital-to-analog converters; and a plurality of threshold voltage compensation circuits, wherein each threshold voltage compensation circuit is connected between one of the plurality of converting transistors and one of the plurality of digital-to-analog converters, each of the plurality of threshold voltage compensation circuits comprising: a compensation transistor having a gate and a first source/drain coupled to a gate of the converting transistor, and a second source/drain coupled to the output voltage; and a reset switch for coupling a reset signal to the gate of the converting transistor, wherein a voltage of the reset signal is lower than a lowest gamma voltage of the gamma voltages by a threshold voltage of the compensation transistor.