RA8816 Datasheet, PDF (35/68 Pages) RAIO Technology Inc. – 144x65 Character/Graphic LCD Driver Specification

Preliminary Version 1.6
6-4-1 Booster Circuit
RA8816
144x65 Character/Graphic LCD Driver
VDD
C1P
C1M
C2P
C2M
C3P
VLCD
VSS
4X Step-up Voltage Circuit
VDD
C1P
C1M
C2P
C2M
C3P
VLCD
VSS
3X Step-up Voltage Circuit
VDD
C1P
C1M
C2P
C2M
C3P
VLCD
VSS
2X Step-up Voltage Circuit
VLCD=4xVDD=12V
VLCD=3xVDD=9V
VDD=3V
VDD=3V
VSS=0V
4X Step-up Voltage Relationships
VSS=0V
3X Step-up Voltage Relationships
VLCD=2xVDD=6V
VDD=3V
VSS=0V
2X Step-up Voltage Relationships
Figure 6-24: Application circuit of Booster
The RA8816 built-in a Booster which create 2~4 times of “V_DD-V_SS” that we called “VLCD”. The
VLCD is supply the power for next stage curcuit – Voltage Regulator and internal Driver cuicuit. If
connect an 1uF capacitor on pin C1P and C1M, then the VLCD is eaual to 2*VDD. If the pin C2P
and C2M also connect n 1uF capacitor then the VLCD is 3*VDD. If the pin C3P and C1M connect n
1uF capacitor then the VLCD is 4*VDD. Refer to the following description of Figure 6-24.
Because the RA8816 supports maximumn LCD panel is 144x65. Therefore sometimes you can get
the good display quality that base on lower power such as 5V only. In that case, user only need to
connect 5V to VDD, VLCD, C1P and C2P. And you do not need to add capacitor on C1P/C1M and
C2P/C2M.
The clock source of Booster is also control by register DRCR_B. Please refer to the description of
REG[12h] in Chapter 5-2. Normally, if use the internal Driver Power, then the application circuit is
follow Figure 6-25. If use external VLCD, that means do not use the internal Booster, then the
connection is show as Figure 6-26.
RAiO TECHNOLOGY INC.
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www.raio.com.tw