Non-multiplexed LCD drive circuit

摘要

A liquid crystal display circuit (9) comprises a recirculating shift register (14) having serial input and output terminals for receiving and generating binary data in bit serial format and a plurality of intermediate parallel output terminals for coupling display data to a liquid crystal display (LCD) (10). Display data are loaded into the shift register (14) during a display update mode and recirculated for display by the LCD (10) during a data refresh mode. Loading and recirculation of display data are controlled by logic circuitry (16) in a feedback loop (15, 17) of the recirculating shift register (14). To minimize DC buildup on the LCD (10), data inversion provided in the feedback loop causes periodic polarity reversal of data during recirculation. In addition, a shift register reset circuit (28) monitors the continuity of data being supplied to the LCD (10) for display. The reset circuit (28) resets the shift register (14) in response to discontinuities in input data flow to further minimize DC buildup.