Philips Semiconductors
Product specification
Universal LCD driver for low multiplex
rates
PCF8566
handbook, full pagewidth
Tframe
VDD
BP0
(VDD
+
VLCD)/2
VLCD
VDD
BP1
(VDD
+
VLCD)/2
VLCD
VDD
Sn
VLCD
VDD
Sn
+
1
VLCD
(a) waveforms at driver
Vop
Vop/2
state 1
0
−V
op/2
−V
op
Vop
Vop/2
state 2
0
−V
op/2
−V
op
(b) resultant waveforms
at LCD segment
MGG394
LCD segments
state 1
state 2
At any instant (t):
Vstate 1(t) = VS (t)
−
VBP0(t)
n
V
Von(rms) = op
√10
= 0.791Vop
4
Vstate 2(t) = VS (t)
−
VBP1(t)
n
Vop
√2
= 0.354Vop
Voff(rms) =
4
Fig.5 Waveforms for 1 : 2 multiplex drive mode with
1
⁄
2
bias: V
op
= V
DD
−
V
LCD
.
1998 May 04
9