Display driver circuits

A power controller for a display driver for an electroluminescent display, the display comprising a plurality of electroluminescent display elements each associated with a display element driver circuit, each said display element driver circuit including a drive transistor having a control connection for driving the associated display element in accordance with a voltage on the control connection, the power controller comprising:

• a memory storing processor control code;
• a processor coupled to the memory for executing said processor control code;
• a sensed voltage input for sensing a voltage on a said control connection;
• and
• a control signal output for controlling an adjustable power supply for providing an adjustable voltage to said electroluminescent display to power said drive transistors for driving said display elements;
• said processor control code comprising instructions for controlling the processor to read said sensed voltage input and to output a control signal to adjust said power supply in response to said sensed voltage.

A method of operating an active matrix electroluminescent display, the display comprising a plurality of pixels each with an associated pixel driver, the display having a power supply and plurality of control lines for setting the brightness of each pixel, the method comprising:

• setting the brightness pixels of the display using said control lines;
• monitoring control lines of the display;
• and
• reducing said power supply responsive to said monitoring.