Patent ID: 7355574

Claim:
A compensated drive circuit adjusting for changes in the threshold voltage of a drive transistor and for aging of an OLED device, comprising: a. a data line carrying analog data representative of the brightness level desired from the OLED device, and a select line; b. the drive transistor connected to a power supply and to the OLED device such that when the select line is activated and a voltage from the data line is applied to the gate electrode of such transistor, current proportional to the applied voltage will flow through the drain and source electrodes through the OLED device; c. means for measuring first and second parameters associated with the drive circuitry, the first parameter being a function of the voltage across the OLED device, and the second parameter being a function of the current passing through the OLED device; and d. means responsive to the measured first and second parameters for computing offset voltages to be applied to the data line analog voltages to adjust for changes in the threshold voltage of the drive transistors and for aging of the OLED device.