Patent ID: 7800558

Claim:
Display driver control circuitry for controlling a display driver for an electroluminescent display, the display comprising a plurality of electroluminescent display elements, the driver including a plurality of substantially constant current generators for simultaneously driving said plurality of display elements, each said constant current generator being configured for regulating the current on an associated display drive line driving a set of said electroluminescent display elements, the display driver control circuitry comprising: a drive voltage sensor for sensing a voltage on a first line in which the current is regulated by said constant current generator; a voltage controller coupled to said drive voltage sensor for controlling the voltage of a supply for said constant current generator in response to said sensed voltage, and configured to control said supply voltage to increase the efficiency of said display driver, wherein said voltage controller is configured to reduce said supply voltage when this will not substantially reduce said regulated current and/or said display brightness; a drive voltage sensor for sensing the voltage on each said display drive line; a maximum voltage detector to detect a maximum voltage from among the voltages sensed on each of said display drive lines; a difference detector to detect a difference between said maximum voltage and said supply voltage; and a comparator to compare said difference with a threshold defining an estimated compliance limit of a said constant current generator, and wherein said voltage controller is responsive to an output of said comparator to control said supply voltage such that a said constant current generator driving said drive line having said detected maximum voltage operates in the vicinity of the compliance limit of the said constant current generator.