Philips Semiconductors
LCD driver for low multiplex rates
Product specification
OM4068
Table 3 LCD drive modes: summary of characteristics
LCD DRIVE
NUMBER OF
MODE BACKPLANES LEVELS
LCD BIAS
CONFIGURATION
Static
1
1:2
2
1:3
3
2
static
3
1⁄2
4
1⁄3
V-----o--V-f-f--O-(--r-Pm----s---)-
0
0.354
0.333
V-----o--V-n---O(--r--Pm----s---)
1
0.791
0.638
D = V-V----oo---fn-f--(-(-r-r-mm----ss---))-
−
2.2236
1.915
LCD drive mode waveforms
The static LCD drive mode is used when a single backplane is provided in the LCD. Backplane and segment drive
waveforms for this mode are shown in Fig.5.
handbook, full pagewidth
VLCD
BP1
VSS
SEG N
(off)
VLCD
VSS
VLCD
SEG N + 1
(on)
VSS
Tframe
VLCD
0V
−VLCD
VLCD
0V
−VLCD
SEG − BP1
MBK819
BACKPLANE
DRIVER OUTPUT
BP1
SEGMENTS
SEG N SEG N + 1
off
on
Fig.5 Static drive mode waveforms (VOP = VLCD − VSS).
1998 Jun 18
10