Patent ID: 7834824

Claim:
A display driver for an active matrix electroluminescent display, the display comprising a plurality of electroluminescent pixels each pixel comprising a pixel driver circuit and a display element, each said pixel driver circuit including a drive field effect transistor having a gate connection for driving the associated display element in accordance with a voltage on the gate connection to produce a driving current through said display element, the display driver comprising: a display element brightness controller configured to provide an output to drive a said gate connection to control the electroluminescent output from a said pixel; a voltage sensor to sense a said voltage on said gate connection; and a power controller coupled to said voltage sensor for controlling an adjustable voltage power supply to each of said plurality of electroluminescent pixels, said power controller configured to read a sensed voltage on each said pixel gate connection within a predetermined period to identify a display element having a maximum brightness relative to others of said display elements within said predetermined period, wherein said display element brightness controller and said power controller are configured to, respectively and concurrently within a period, increase said voltage on said gate connection of said pixel having said identified display element and to reduce said power supply voltage, to a point where the voltage of said adjustable voltage power supply is just sufficient to maintain a current to said identified display element substantially equal to a predetermined current corresponding to a current that is produced in said identified display element prior to said increasing of said voltage on said gate connection and said reducing of said power supply voltage, said increasing and said reducing in response to a said sensed voltage on said gate connection of said pixel having said identified display element, wherein said increasing and said reducing are performed as long as said sensed voltage on said gate connection is determined to be less than a maximum available voltage for outputting from said brightness controller to said display element and until said voltage on said gate connection substantially reaches said maximum available voltage.