NJU6677 데이터 시트보기 (PDF) - Japan Radio Corporation

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NJU6677

88-common x 132-segment BIT MAP LCD DRIVER

Japan Radio Corporation  

NJU6677

(f) Oscillation Circuit

The Oscillation Circuit is a low power CR oscillator incorporating with Resistor and Capacitor. It generates

clocks for display timing signal source and voltage booster circuits. The oscillation circuit output frequency is

divided as shown in below for display clock CL.

-The relation between duty and divide

Duty

Divide

1/8

1/44

1/16

1/22

1/24

1/15

1/32

1/11

1/40

1/9

1/48

1/7

1/56,64

1/6

1/72

1/5

1/80,88

1/4

(g) Power Supply Circuit

Internal Power Supply Circuit generate the High voltage and Bias voltage for the LCD. The power Supply

Circuit consists of Voltage Booster (5-Time maximum) Circuits, Regulator Circuits, and Voltage Followers.

The internal Power Supply is designed for small size LCD panel, therefore it is not suitable for the large size

LCD panel application. If the contrast is not good in the large size LCD panel application, please supply the

external.

The suitable values of the capacitors connecting to the V1 to V5 terminals and the voltage booster circuit, and

the feedback resistors for V5 operational amplifier depend on the LCD panel. And the power consumption with

the LCD panel is depending on the display pattern. Please evaluate with actual LCD module.

The operation of internal Power Supply Circuits is controlled by the Internal Power Supply On/Off Instruction.

When the Internal Power Supply Off Instruction is executed, all of the voltage booster circuits, regulator

circuits, voltage follower circuits are turned off. In this time, the bias voltage of V1, V2, V3, V4, and V5 for the

LCD should be supplied from outside, terminals C1+, C1-, C2+, C2-, C3+, C3-, C4+, C4- and VR should be open.

The status of internal power supply is selected by T1 and T2 terminal. Furthermore the external power supply

operates with some of internal power supply function.

T1

T2

Voltage

Booster

Voltage Adj.

Buffer(V/F)

Ext.Pow Supply

C1+,C1- to

C4+,C4-

VR Term.

L

L/H

ON

ON

ON

-

H

L

OFF

ON

ON

VOUT

Open

H

H

OFF

OFF

ON

V5,VOUT

Open

Open

When (T1, T2)=(H, L), C1+, C1-, C2+, C2-,C3+, C3-, C4+, C4- terminals for voltage booster circuits are open

because the voltage booster circuits doesn't operate. Therefore LCD driving voltage to the VOUT terminal

should be supplied from outside.

When (T1, T2)=(H, H), terminals for voltage booster circuits and VR are open, because the voltage booster

circuits and Voltage adjust circuits do not operate.

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