ST7567 View Datasheet(PDF) - Unspecified
Part Name
Description
MFG CO.
'ST7567' PDF : 73 Pages View PDF
ST7565S
The Voltage Regulator Circuit
The step-up voltage generated at VOUT outputs the LCD
driver voltage V5 through the voltage regulator circuit.
Because the ST7565S chips have an internal high-accuracy
fixed voltage power supply with a 64-level electronic volume
function and internal resistors for the V5 voltage regulator,
systems can be constructed without having to include
high-accuracy voltage regulator circuit components.
(VREG thermal gradients approximate -0.05%/°C)
(A) When the V5 Voltage Regulator Internal Resistors Are Used
Through the use of the V5 voltage regulator internal resistors
and the electronic volume function the liquid crystal power
supply voltage V5 can be controlled by commands alone
(without adding any external resistors), making it possible to
adjust the liquid crystal display brightness. The V5 voltage
can be calculated using equation A-1 over the range where
| V5 | < | VOUT |.
( ) V5 =
1+
Rb
Ra
VEV
( ) ( ) =
1+
Rb
Ra
1-
α
162
VREG
[ ( ) ] ∵ VEV =
1-
α
162
VREG
Internal Ra
VDD
VEV(constant voltage supply+electronic volume)
V5
Internal Rb
Figure 8
Ver 0.3c
33/72
2002/07/22
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