Control of electroluminescent displays

摘要

A controller 2 is provided for use with a multi-segment electroluminescent display 1. Control signals C1-C5 control a plurality of half H-bridges H1-H5, the terminals of the half H-bridges being connected respectively to ground 10 and to a high voltage DC supply 9 so that the half H-bridges each provide an AC voltage. One of said half H-bridges provides a common output Vcommon and the remaining H-bridges provide drive voltages V1-V4 for the segments of the display. During each cycle, the controller 2 causes the drive outputs V1-V4 to either be in phase or in anti-phase with the common output Vcommon. This selectively turns the segments on and off at a rate much higher than the human eye can perceive. The brightness of the segments is controlled by varying the proportion of the time that each segment is illuminated.