ST7565P datasheet(33/71 Pages) SITRONIX

33 / 71 page

ST7565P

Ver 2.1b

33/71

2009/09/14

The Voltage Regulator Circuit

The step-up voltage generated at VOUT outputs the LCD

driver voltage V0 through the voltage regulator circuit.

Because the ST7565P chips have an internal high-accuracy

fixed voltage power supply with a 64-level electronic volume

function and internal resistors for the V0 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 V0 Voltage Regulator Internal Resistors Are Used

Through the use of the V0 voltage regulator internal resistors

and the electronic volume function the liquid crystal power

supply voltage V0 can be controlled by commands alone

(without adding any external resistors), making it possible to

adjust the liquid crystal display brightness. The V0 voltage

can be calculated using equation A-1 over the range where |

V0 | < | VOUT |.

(

)

VEV

V0 =

(

)

(1 -

162 )

VREG

[∵ VEV = (1 -

162 )

VREG

]

Internal Ra

VEV(constant voltage supply+electronic volume)

VSS

Internal Rb

Figure 8

ST7565P Datasheet(PDF) 33 Page - Sitronix Technology Co., Ltd.