Lcd Controller/Driver External Voltage Divider - Fujitsu Semiconductor Controller MB89950/950A Hardware Manual

12.2.2

LCD Controller/Driver External Voltage Divider

External voltage divider can also be used with devices that have internal voltage divider.
Display brightness can be adjusted by a variable resistor(VR) connected between the
V and V3 pins.
CC
I External voltage divider
When you do not wish to use the internal voltage divider, external voltage divider resistors can be
connected at the LCD drive voltage supply pins (V1 to V3). Figure 12.2-5 "External voltage divider
connection" shows connection for external voltage divider for the two biasing modes, and Table 12.2-1
"LCD drive voltages and biasing modes" lists the corresponding LCD drive voltages.
MB89950/950A series
1/2 bias
Table 12.2-1 LCD drive voltages and biasing modes
V1 to V3: Voltages at pins V1 to V3.
VLCD: LCD operating voltage
Figure 12.2-5 External voltage divider connection
Vcc
VR
V3
R
V2
V1
R
Bias
1/2 bias
1/3 bias
CHAPTER 12 LCD CONTROLLER/DRIVER
V
LCD
MB89950/950A series
1/3 bias
LCD drive voltages
V3
VLCD 1/2VLCD
VLCD 2/3VLCD
Vcc
VR
V3
R
V2
V
LCD
R
V1
R
V2
1/2VLCD
1/3VLCD
V1
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