NXP Semiconductors
PCF8533
Universal LCD driver for low multiplex rates
7.4.4 1:4 multiplex drive mode
The 1:4 multiplex drive mode is used when four backplanes are provided in the LCD as
shown in Figure 8.
PCF8533_4
Product data sheet
BP0
BP1
BP2
BP3
Sn
Sn+1
Sn+2
Sn+3
state 1
state 2
VLCD
2VLCD / 3
VLCD / 3
VSS
VLCD
2VLCD / 3
VLCD / 3
VSS
VLCD
2VLCD / 3
VLCD / 3
VSS
VLCD
2VLCD / 3
VLCD / 3
VSS
VLCD
2VLCD / 3
VLCD / 3
VSS
VLCD
2VLCD / 3
VLCD / 3
VSS
VLCD
2VLCD / 3
VLCD / 3
VSS
VLCD
2VLCD / 3
VLCD / 3
VSS
VLCD
2VLCD / 3
VLCD / 3
0V
−VLCD / 3
−2VLCD / 3
−VLCD
VLCD
2VLCD / 3
VLCD / 3
0V
−VLCD / 3
−2VLCD / 3
−VLCD
Tfr
(a) Waveforms at driver.
(b) Resultant waveforms
at LCD segment.
Fig 8.
Vstate1(t) = VSn(t) − VBP0(t).
Von(RMS) = 0.577VLCD.
Vstate2(t) = VSn(t) − VBP1(t).
Voff(RMS) = 0.333VLCD.
Waveforms for the 1:4 multiplex drive mode with 1⁄3 bias
LCD segments
state 1
state 2
mgl749
All information provided in this document is subject to legal disclaimers.
Rev. 04 — 5 March 2010
© NXP B.V. 2010. All rights reserved.
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