HD66750 Datasheet, PDF (53/96 Pages) Hitachi Semiconductor – 128 x 128-dot Graphics LCD Controller/Driver with Four-grayscale Functions

VLCD
0.47 µF*
(B characteristics)
GND
O POFF = G ND
V LCD
VR
V 1OUT
R
V 2OUT
R0
V 3OUT
R
V 4OUT
R
V 5OUT
R
GND
HD66750/1
+
-
V1
+
-
V2
LCD
driver
+
-
V3
+
-
V4
+
-
V5
GND
V ci
C1+
C1-
C2+
C2-
C3+
C3-
C4+
C4-
C5+
C5-
C6+
C6-
V LOUT
B ooster
HD66750/1
SEG1 to SEG128
CO M1 to CO M12
Note: A djust the capacitance value of the capacitor after the LCD p anel has b een mounted.
The capacitors connected to V 1OUT to V 5OUT/GND should b e more the V lcd voltage.
The voltage of these capacitors should b e determined with fluctuation of voltage.
Figure 35 External Power Supply Circuit for LCD Drive Voltage Generation
When an Internal Booster and Internal Operational Amplifiers are Used
To supply LCD drive voltage using the internal booster, circuits should be connected as shown in figure 36.
Here, contrast can be adjusted through the CT bits of the contrast control instruction. Temperature can be
compensated either through the CT bits or by controlling the reference voltage for the booster (Vci pin)
using a thermistor.
Note that Vci is both a reference voltage and power supply for the booster. The reference voltage must
therefore be adjusted using an emitter-follower or a similar element so that sufficient current can be
supplied. In this case, Vci must be equal to or smaller than the V_CC level.
53