NJU6624CFG1 データシートの表示（PDF） - Japan Radio Corporation

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NJU6624CFG1

14-CHARACTER 1-LINE DOT MATRIX LCD CONTROLLER DRIVER with SMOOTH SCROLL FUNCTION

Japan Radio Corporation  

NJU6624C

(5)LCD display

(5-1)Bleeder Resistance

Each LCD driving voltage ( V1, V2, V3, V4 ) is LCD driving high voltage input to the VLCD1 terminal, generated by

the E.V.R. and high impedance bleeder resistance.

The bleeder resistance is set 1/4 bias suitable for 1/8 duty ratio.

The capacitor connected between VLCD2 and VSS is needed for stabilizing VLCD. The determination of the each

capacitance requires to operate with the LCD panel actually.

LCD Driving Voltage vs Duty Ratio

Power Duty Ratio

1/8

supply

Bias

1/4

V LCD

VLCD2- VSS

VLCD is the maximum amplitude for LCD driving voltage.

VLCD1

VLCD2

V1

V2

V4

VSS

+

+

+

+

Internal NJU6624

E.V.R.(16Step)

5K

VLCD

4K

V1

4K

V2 (V3)

4K

V4

4K

VSS

VLCD

(5-2)Relation between oscillation frequency and LCD frame frequency

As the NJU6624C incorporate oscillation capacitor and resistor for CR oscillation, 145kHz oscillation is available

without any external components.

The LCD frame frequency example mentioned below is based on 145kHz oscillation.(1clock =6.90us)

224clocks

Icon 1

2

3

.............. 7 K e y Icon 1

2

3

.............. 7 K e y Icon 1 2

VLCD

V1

COM1 V2

V4

VSS

1 frame

1 frame

1 frame = 6.90(us) x 224 x 8 = 12.36(ms)

Frame frequency = 1 / 12.36(ms) = 79.50(Hz)

Key scan time = 220.70(uS)

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