Panasonic KX-TGE210B, Service Manual

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6
3.1.2. Circuit Operation (Handset)
[Changed from original section “4.9. Circuit Operation (Handset)”]
3.1.2.1. Outline
Handset consists of the following ICs as shown in Block Diagram (Handset) (P.5).
• 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
Following information data is stored
- Settings
ex : ID code, user setting
3.1.2.2. 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+) -> Q1 (1.8 V), IC1-44pin (CP3V)
The Reset signal generates IC1 (71 pin) and 1.8 V.
3.1.2.3. Charge Circuit
Circuit Operation:
When charging the handset on the Base Unit, the charge current is as follows;
DC+(5.5 V) -> R371 -> R372 -> D362 -> (Base) -> (Handset) -> -> Q3 -> ... Battery...
BATTERY- -> R45 -> GND -> CHARGE-(Handset) -> CHARGE-(Base) -> GND -> DC-(GND)
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
Power Supply Circuit/Reset Circuit (P.6).
3.1.2.4. Battery Low/Power Down Detector
Circuit Operation:
“Battery Low” and “Power Down” are detected by BBIC which check the voltage from battery.
The detected voltage is as follows;
• Battery Low
Battery voltage: V(Batt) 2.25 V ± 50 mV
The BBIC detects this level and " " starts flashing.
• Power Down
Battery voltage: V(Batt) 2.0 V ± 50 mV
The BBIC detects this level and power down.
1.8V
B
Reset
(IC1_71 pin)
Q2
R8