Compensated drive circuit adjusting for changes in the threshold voltage
of a drive transistor and for aging of an OLED device, comprising: a data
line carrying analog data representative of the brightness level, and a
select line; 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
and current proportional to the applied voltage will flow through the
drain and source electrodes through the OLED device; circuitry for
measuring first and second parameters associated with the drive circuitry
and responsive to the measured first and second parameters for computing
offset voltages to adjust for changes in the threshold voltage of the
drive transistors and for aging of the OLED device.