Table of Contents
Advertisement
14. Dot Matrix LCD Controller (H8/3854 Group)
14.3.12 LCD Drive Bias Selection Circuit
The ideal bias value that gives the best contrast is calculated using the equation shown below. If
drive is performed at a bias value lower than the optimum, contrast will deteriorate, but the LCD
drive voltage (the potential difference between V1 and V
) can be kept low. If the output voltage
SS
falls and the LCD display becomes faint as batteries wear out, for instance, the display can be
made clearer by decreasing the LCD drive bias.
1
Optimum bias value for 1/N duty drive =
N + 1
Notes: 1. When using 1/5 bias, leave the V3OUT and V4OUT pins open.
2. When using 1/4 bias, short the V3OUT and V4OUT pins.
Rev.3.00 Jul. 19, 2007 page 402 of 532
REJ09B0397-0300
Advertisement
Table of Contents
