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