NXP Semiconductors
PCF8576C
Universal LCD driver for low multiplex rates
7.4.2 1:2 Multiplex drive mode
When two backplanes are provided in the LCD, the 1:2 multiplex mode applies. The
PCF8576C allows the use of 1⁄2 bias or 1⁄3 bias (see Figure 9 and Figure 10).
BP0
BP1
Sn
Sn+1
VLCD
VLCD / 2
VSS
VLCD
VLCD / 2
VSS
VLCD
VSS
VLCD
VSS
state 1
state 2
VLCD
VLCD / 2
0V
−VLCD / 2
−VLCD
VLCD
VLCD / 2
0V
−VLCD / 2
−VLCD
Tfr
LCD segments
state 1
state 2
(a) Waveforms at driver.
(b) Resultant waveforms
at LCD segment.
mgl746
Fig 9.
Vstate1(t) = VSn(t) − VBP0(t).
Von(RMS) = 0.791VLCD.
Vstate2(t) = VSn(t) − VBP1(t).
Voff(RMS) = 0.354VLCD
Waveforms for the 1:2 multiplex drive mode with 1⁄2 bias
PCF8576C
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 10 — 22 July 2010
© NXP B.V. 2010. All rights reserved.
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