HD44780U Hitachi Semiconductor (acquired by Renesas), HD44780U Datasheet - Page 38

• Manufacturer Part Number: HD44780U
• Description: Dot Matrix Liquid Crystal Display Controller/driver
• Manufacturer: Hitachi Semiconductor (acquired by Renesas)

HD44780U
Power Supply for Liquid Crystal Display Drive
Various voltage levels must be applied to pins V1 to V5 of the HD44780U to obtain the liquid crystal
display drive waveforms. The voltages must be changed according to the duty factor (Table 10).
VLCD is the peak value for the liquid crystal display drive waveforms, and resistance dividing provides
voltages V1 to V5 (Figure 23).
Table 10
Power Supply
V1
V2
V3
V4
V5
204
Duty Factor and Power Supply for Liquid Crystal Display Drive
1/4 bias
(1/8, 1/11 duty cycle)
Figure 23 Drive Voltage Supply Example
V
V1
V2
V3
V4
V5
CC
1/8, 1/11
1/4
V
V
V
V
V
CC
CC
CC
CC
CC
–1/4 VLCD
–1/2 VLCD
–1/2 VLCD
–3/4 VLCD
–VLCD
V
CC
–5 V
(+5 V)
R
R
R
R
VR
VLCD
1/5 bias
(1/16, duty cycle)
Duty Factor
V
V1
V2
V3
V4
V5
CC
1/16
Bias
1/5
V
V
V
V
V
CC
CC
CC
CC
CC
V
–1/5 VLCD
–2/5 VLCD
–3/5 VLCD
–4/5 VLCD
–VLCD
CC
–5 V
(+5 V)
VR
R
R
R
R
R
VLCD