Abstract: An improved drive circuit for operating an electroluminescent display includes a circuit for biasing column and row drivers to maximize the energization voltage for illuminated pixels without reducing the contrast of the display. Interface circuitry is also provided for detecting the beginning of valid data for each line to be displayed, checking the selected display mode of the line and adjusting the timing of a system clock to completely and uniformly display characters in the 40-column, 80-column or graphics display mode.