Common driver (hd61203), Bias voltage generator – Seiko Instruments G1216B1N000-3D0E User Manual
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AN.No.G1216B1N000-3D0E
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Y-address counter
This counter sets the address by instruction and is automatically advanced by the read/write
operation. Counting is performed by looping the values 0 to 63.
2.3 Common driver (HD61203)
The common driver is a 64 drive output CMOS IC. Incorporating an oscillation circuit, this driver
generates the common signal and timing signals (LC AC drive control, and one-frame timing signal)
necessary for the LC display, and controls the display by supplying the timing signals to the segment
drivers.
2.4 Bias voltage generator
Six levels of standard voltage Va to Vf are applied to the drivers as a bias voltage. This voltage is
generated by resistance division of Vopr and driven by a voltage follower through an operational
amplifier.
C
R
1
V
opr
V
DD
1 / 9 bias: R
2
= (9
4) R
1
= 5 R
1
V
a
V
b
V
c
V
d
V
e
V
f
Operational
Amplifier
Figure 7 Bias Voltage Generator
C
R
1
C
R
2
C
R
1
C
R
1
+
+
+
+
V
LC