An apparatus for establishing and applying a voltage to precharge current-driven elements in a matrix. During ordinary scan cycles, a conduction voltage is sensed while the elements conduct a selected current. One or more such sensed conduction voltages are combined to provide a basis for a precharge voltage. Conduction and transient errors are determined, and are compensated for by offsetting the final precharge voltage from the conduction voltage basis. The final precharge voltage is provided to one or more columns during a precharge period of the scan cycle.