Panasonic KX-TG8105RU, Service Manual

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KX-TG8105RU/KX-TG8106RU/KX-TGA810RU
4.2. Circuit Operation (Base Unit)
4.2.1. Outline
Base Unit consists of the following ICs as shown in Block Diagram (Base Unit) (P.7).
• DECT BBIC ( B ase B and IC): IC7
- Handling all the audio, signal and data processing needed in a DECT base unit
- Controlling the DECT specific physical layer and radio section (
B urst M odule C ontroller section)
- ADPCM code filter for speech encoding and speech decoding (DSP section)
- Echo-cancellation and Echo-suppression (DSP section)
- Any tones (tone, sidetone, ringing tone, etc.) generation (DSP section)
- DTMF receiver (DSP section)
- Clock Generation for RF Module
- ADC, DAC, timer, and power control circuitry
- All interfaces (ex: RF module, EEPROM, LED, Analog Front End, etc.)
• RF Module: IC10
- PLL Oscillator
- Detector
- Compress/Expander
- First Mixer
- Amplifier for transmission and reception
• EEPROM: IC5
- Temporary operating parameters (for RF, etc.)
• Additionally,
- Power Supply Circuit (+3.3V, +2.5V, +1.8V output)
- Crystal Circuit (10.368MHz)
- Charge Circuit
- Telephone Line Interface Circuit
4.2.2. Power Supply Circuit
The power is supplied to the DECT BBIC, RF Module, EEPROM and Charge Contact from AC Adaptor (+6.5V) as shown in
Fig.101. The power supply is as follows;
• DECT BBIC (IC7):
CN2 (+6.5V)
→
IC1
→
Q9
→
IC7
CN2 (+6.5V)
→
IC1
→
Q8
→
IC7
• RF Module (IC10):
CN2 (+6.5V)
→
IC1
→
Q9
→
IC10 (PLL)
CN2 (+6.5V)
→
IC1
→
Q10
→
IC10 (Power AMP)
• EEPROM (IC5):
CN2 (+6.5V)
→
IC1
→
Q9
→
IC5
• Charge Contact (TP16):
CN2 (+6.5V)
→
R55, R56
→
TP16
<Fig.101>