Panasonic KX-TGA950B, Service Manual

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KX-TG9581B/KX-TG9582B/KX-TGA950B
4.4. Circuit Operation (Handset)
4.4.1. Outline
Handset consists of the following ICs as shown in Block Diagram (Handset) (P.15).
• DECT BBIC ( B ase B and IC): IC1
- All data signals (forming/analyzing ACK or CMD signal)
- All interfaces (ex: Key, Detector Circuit, Charge, DC/DC Converter, EEPROM, LCD, RF Power Amp.)
- PLL Oscillator
- Detector
- Compress/Expander
- Reception
- Integrated 1.9 GHz PA for DECT
• QSPI FLASH MEMORY: IC4
- Main Program D/L Area
• EEPROM: IC3
- Temporary operating parameters (for RF, etc.)
4.4.2. Power Supply Circuit/Reset Circuit
Circuit Operation:
When power on the Handset, the voltage is as follows;
BATTERY(2.2 V ~ 2.6 V: BATT+)
→
F1
→
Q1 (1.8 V), IC1-44pin (3.0V)
The Reset signal generates IC1 (71 pin) and 1.8 V.
4.4.3. Charge Circuit
Circuit Operation:
When charging the handset on the charger, the charge current is as follows;
In this way, the BBIC on Handset detects the fact that the battery is charged.
The charge current is controlled by switching Q9 of Handset.
Refer to Fig.101 in Power Supply Circuit (P.10).
1.8 V
Reset
(IC1_61pin)
B
(Charger) --> (Handset) --> R8 --> Q 3 --> F1 --> BATTERY (+) -->
BATTERY(-) --> R45 --> GND --> CHARGE-(Handset) --> CHARGE-(Charger)