PCF8566
NXP Semiconductors
Universal LCD driver for low multiplex rates
7.4.3 1:3 Multiplex drive mode
When three backplanes are provided in the LCD, the 1:3 multiplex drive mode applies as
shown in Figure 8.
T
fr
V
LCD
2V
LCD segments
/ 3
LCD
/ 3
BP0
BP1
BP2
Sn
V
V
LCD
SS
state 1
state 2
V
LCD
2V
/ 3
LCD
/ 3
V
V
LCD
SS
V
LCD
2V
/ 3
LCD
/ 3
V
V
LCD
SS
V
LCD
2V
/ 3
LCD
/ 3
V
V
LCD
SS
V
LCD
2V
/ 3
LCD
/ 3
Sn+1
V
V
LCD
SS
V
LCD
2V
/ 3
LCD
/ 3
Sn+2
V
V
LCD
SS
(a) Waveforms at driver.
V
LCD
2V
/ 3
LCD
/ 3
V
LCD
0 V
−V
state 1
/ 3
LCD
−2V
/ 3
LCD
−V
LCD
V
LCD
2V
/ 3
/ 3
LCD
V
LCD
0 V
−V
state 2
/ 3
LCD
−2V
/ 3
LCD
−V
LCD
(b) Resultant waveforms
at LCD segment.
mgl748
Vstate1(t) = VSn(t) − VBP0(t).
Von(RMS) = 0.638VLCD
.
Vstate2(t) = VSn(t) − VBP1(t).
Voff(RMS) = 0.333VLCD.
Fig 8. Waveforms for the 1:3 multiplex drive mode with 1⁄3 bias
PCF8566_7
© NXP B.V. 2009. All rights reserved.
Product data sheet
Rev. 07 — 25 February 2009
13 of 48
NXP [ NXP ]
