Panasonic KX-A142EXM - Page 59

21. BLOCK DIAGRAM (HANDSET)
22. CIRCUIT OPERATION (HANDSET)
22.1. Outline
Handset consists of the following ICs as shown in BLOCK DIAGRAM (HANDSET) ().
- DECT BBIC (Base Band IC): IC1
- All data signals (forming/analyzing ACK or CMD signal)
- All interfaces (ex: Key, Detector Circuit, Charge, DC/DC Converter,
EEPROM, LCD)
- RF Module: IC3
- PLL Oscillator
- Detector
- Compress/Expander
- Amplifier for transmission and reception
- EEPROM (IC2)
- Temporary operating parameters (for RF, etc.)
Note:
Refer to EEPROM LAYOUT (HANDSET) ().
22.2. Power Supply Circuit/Reset Circuit
Circuit Operation:
When power on the Handset, the voltage is as follows;
BATTERY(2.2 V ~ 2.6V: TP3) TP14(4V) IC3(6, 27), D3 IC1(37) IC1(39, 63) (2.65V)
The Reset signal generates R19, C23 and 2.65V.
22.3. Charge Circuit
Circuit Operation:
- When charging the handset on the Base Unit, the charge current is
as follows;
DC+(5.5V ~ 6V) D4 R43, R44 CHARGE+(Base) CHARGE+
(Handset) L4 Q2 F1 BATTERY+ ... Battery ... BATTERY-
R21 GND L5 CHARGE-(Handset) CHARGE-(Base)
GND DC-(GND)
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1/2/2015
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