LCD control unit - has multiplexed operation control with facility to operate under wide range of ambient temp.

摘要

A control voltage circuit for liquid crystal display systems of the type employed in digital wristwatches is designed to maintain a correct multiplexed control mode for a range of ambient temperatures. The liquid crystal display (1) includes an unregulated supply (3) and has an oscillator circuit to control the timing of the multiplexed (2) mode of operation. The unregulated voltage supply is controlled by a voltage control stage (5) that includes a constant voltage stage (6). A voltage doubling stage (4) connects with the multiplexer. The voltage control stage, voltage doubler and multiplexer are produced in a single integrated circuit (34).