A method and system for controlling a voltage used for precharging current-driven
elements in a matrix, and a method of manufacturing a device to perform this function.
Elements are driven during successive scan cycles, each having a precharge period
and an exposure period. The elements conduct current during conduction periods,
which typically have variable length within exposure periods. Conduction voltages
are sensed at earlier times (e.g., near the beginning) and later times (e.g., near
the end) within conduction periods. A precharge voltage is adapted based on a comparison
of the earlier and later sensed conduction voltages, typically so as to reduce
any average difference and thereby cause the voltage during exposure to be consistent.