Panasonic KX-T7636RU Service Manual ▷ View online
10.2. LCD CIRCUIT
LCD data are outputted from pin 57, 58, 59,10 and 12 of IC3 to LCD module.
IC8 is an inverter for a charge pump circuit which outputs the voltage necessary for LCD driving.
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IC8 is an inverter for a charge pump circuit which outputs the voltage necessary for LCD driving.
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• 4.5V from -1.2V generated at IC8 as a reference to +3.3V of the power supply voltage is pressurized four times in the LCD
module and used as LCD driving voltage (approx. 18V).
LCD contrast is set by electronic volume in the LCD module.
The type of the LCD module is distinguished by pin 62 of IC3.
The type of the LCD module is distinguished by pin 62 of IC3.
Pin 62 of IC3
L
KX-T7636
24 digits * 6 lines
H
KX-T7630/KX-T7633
24 digits * 3 lines
The lighting of the backlight is controlled by Q1.
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• IC3-pin 56 H→Q1-ON→Backlight ON
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• IC3-pin 56 L→Q1-OFF→Backlight OFF
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KX-T7636RU-B
10.3. LED CIRCUIT
The lighting of the LED is controlled by pin 19 to 28 (Row) and pin 11 to 16 (Colum) of IC5.
The LED lights up in a dynamic lighting system.
The duty ratio is 1/8 (ON time 1.5ms).
The LED lights up in a dynamic lighting system.
The duty ratio is 1/8 (ON time 1.5ms).
Only D107 of LED for CO7 lights up in a static lighting system.
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• IC5-pin 55 H : CO7 Green ON
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• IC5-pin 55 L : CO7 Green OFF
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• IC5-pin 56 H : CO7 Red ON
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• IC5-pin 56 L : CO7 Red OFF
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KX-T7636RU-B
10.4. RESET CIRCUIT
Reset Signal is outputted from IC1 and inputted into IC3 and IC5 at the connection of TEL cord.
10.5. POWER SUPPLY CIRCUIT
This circuit converts the voltage supplied from PBX into the power supply voltage of +3.3V by IC6 (Switching Regulator IC).
IC10 controls the power supply circuit as below to turn IC6 on in low consumption current at starting up.
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IC10 controls the power supply circuit as below to turn IC6 on in low consumption current at starting up.
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• Input Voltage approx. 20V or less →IC10-pin 1 L →IC6 OFF
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• Input Voltage approx. 20V or more →IC10-pin 1 HiZ→IC6 ON
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KX-T7636RU-B
10.6. DATA COMMUNICATION
Function
The data communication circuit serves the following functions:
Information exchanger between PBX and proprietary telephone, key input information as well as data for the LED control, LCD
control, voice data, etc. This information is continuously exchanged at all times.
Information exchanger between PBX and proprietary telephone, key input information as well as data for the LED control, LCD
control, voice data, etc. This information is continuously exchanged at all times.
Circuit Operation
The data received from PBX is inputted to the comparator (pin 68) built in IC5 through Pulse Trans T1. The threshold voltage
of the comparator is determined by R62 to 64 and inputted to pin 67 and 29.
The data to PBX is outputted from pin 70 and 71 of IC5, drives T1 by Transistor Q2 and transmitted.
of the comparator is determined by R62 to 64 and inputted to pin 67 and 29.
The data to PBX is outputted from pin 70 and 71 of IC5, drives T1 by Transistor Q2 and transmitted.
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KX-T7636RU-B
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