UPD78F1502AGK-GAK-AX Datasheet, PDF (721/1031 Pages) Renesas Technology Corp – 16-Bit Single-Chip Microcontrollers

78K0R/Lx3
CHAPTER 16 LCD CONTROLLER/DRIVER
Figure 16-32. Examples of LCD Drive Power Connections (Internal Voltage Boosting Method)
(a) 1/3 bias method
(b) 1/4 bias method
VDD
VDD
Drive voltage
generator
Internal reference
voltage generator
3xVLC2
VLC0
2xVLC2
VLC1
VLC2
C2
VLC3/P02^Note
C3 C4
CAPH
C1
CAPL
Drive voltage
generator
Internal reference
voltage generator
4xVLC3
3xVLC3
VLC0
VLC1
2xVLC3
VLC2
VLC3
CAPH ^{C2 C3 C4 C5}
C1
CAPL
Note VLC3 can be used as port (P02).
Remark Use a capacitor with as little leakage as possible.
In addition, make C1 a nonpolar capacitor.
Remark Use a capacitor with as little leakage as possible.
In addition, make C1 a nonpolar capacitor.
16.8.3 Capacitor split method
The 78K0R/Lx3 microcontrollers contain an internal voltage reduction circuit for generating LCD drive power supplies.
The internal voltage reduction circuit and external capacitors (0.47 μF±30%) are used to generate an LCD drive voltage.
Only 1/3 bias mode can be set for the capacitor split method.
Different from the external resistance division method, there is always no current flowing with the capacitor split method,
so current consumption can be reduced.
Table 16-11. LCD Drive Voltages (Capacitor Split Method)
Bias Method
LCD Drive Voltage Pin
VLC0
VLC1
VLC2
VLC3
VDD
2/3 x VDD
1/3 x VDD
1/3 Bias Method
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R01UH0004EJ0501 Rev.5.01
705
Jun 20, 2011