hd61603r ETC-unknow, hd61603r Datasheet - Page 27

• Manufacturer Part Number: hd61603r
• Description: Segment Type Lcd Driver
• Manufacturer: ETC-unknow

HD61602/HD61603
When Internal Drive Power Supply Is Used
When the internal drive power supply is used, attach C1–C4 for charge pump circuits and variable
resistance R1 for deciding display drive voltage to HD61602 as shown in Figure 20.
Internal voltage is available by setting external voltage switching bits of mode setting data 0.
Figure 21 shows voltage characteristics between VDD and VREF1. Voltage is divided at R1, and then
input into VREF2. Voltage between VDD and VREF2 is equivalent to ÆV in Figure 21, and so VLCD
can be changed by regulating the voltage.
VREF2 is usually regulated by variable resistance, but when replacing R1 with two nonvariable
resistances take VREF1 between max and min into consideration as shown in Figure 21.
Internal drive power supply is generated by using capacitance, and so large current cannot flow. When
large liquid crystal display panel is used, examine the external drive power supply.
1256
Power
LCD
R1 = 1 M variable
C1 = 0.3 F
C2–C4 = 0.3 F
C5 = 0.1 to 0.3 F
C6
1 F
r
1
C5
R1
r
C2
C3
C4
2
C6
Figure 20 Example
23–26
11
16
17
18
19
20
21
22
77
76
75
1
VDD
VSS
Vref1
Vref2
VC1
VC2
V1
V2
V3
COM
SEG0
SEG1
SEG2
2
3
(V1 – VDD)
(V1 – VDD)
+
–
HD61602
Regulator
Voltage follower
Charge
circuit
pump