KX-HDV100 - Panasonic PBX Service Manual Supplement (repair manual). Page 8

8

LCD data are output from pin 

139

 of IC302 to LCD module.

LCD contrast is set by electronic control in LCD module.
+3.3V of the power supply voltage is pressurized about four/three times in the LCD module and used as LCD driving voltage
(approx. 10V).
The driving voltage is observed at pin12(VLCDIN) of CN2.

The lighting of the backlight is controlled by Q301.
The PWM (Pulse Width Modulation) signal is output from IC302 (pin 

102

) pin and the brightness is changed according to its duty

ratio.

Reset Signal is output from IC301 and input into IC302-pin 

16

.

1

2

4

3

5

1

2

4

3

5

To Pin R1 (KEY_COL7) of IC302 

To Pin D13 (RF_SDATA_IN/SD D3) of IC302 

6

To Pin R11 (PWM0) of IC302 

To Pin A9 (SPI2CK) of IC302 

To Pin B10 (SPI2DI) of IC302 

To Pin B9 (SPI2DO) of IC302 

6

C130 

C131

R116

C134

CN2

1

CS0

2

RST

3

CD

4

SCL

5

SI

6

VDD

7

VSS

8

VB0+

9

VB0-

10

VB1-

11

VB1+

12

VLCDIN

DGND

R135

DGND

3.3V

DGND

C132

C129

DGND

R142

R141

R140

R139

L106

R137   

L108

L110

L111

C136

DGND

DGND

C137

To LCD

Q301

4.7k

47k

DGND

BL_A

DGND

Q302

5

3

4

2

6

1

BL_K

R329

R330

LED_VDD

BLB_KBLB_A

D311

R305

DGND

C326

C327

VDD3.3V

DGND

IC301

1

VSS

2

VDD

3

CD

4

OUT

DC_POWER

PWR_RST

IC302

RSTN

L12

DGND

C328