Large Lcd Display Buffering Driver Circuit

  
Large LCD devices of 1 or more exhibit a large driving capacitance to the driver circuits. To solve this problem, the drive circuit shown (see the figure) introduces a buffer amplifier for each of the three common lines. Each amplifier can be programmed independently for a quiescent current of 10, 100, or 1000 jllA. In this application, the bias network applies a voltage that sets the three quiescent currents to 100 uA. The display driver and triple op amp operate between 5 V and ground, and the COM signals range from 5 V to ~ 1 V. To ensure that these signals remain within the amplifiers` common-mode range, the signals are attenuated by one-half and the buffers operate at a gain of two.
Large Lcd Display Buffering Driver Circuit - schematic

The circuit drives eight 1-inch displays, and is suitable for ambient temperature variations of 15uF or less. At the highest expected temperature, R1 should be adjusted so that no off segments are visible.




Leave Comment

characters left:

New Circuits

.