DOWNLOAD Panasonic KX-TG6451CAT / KX-TGA641RUT Service Manual ↓ Size: 3.14 MB | Pages: 94 in PDF or view online for FREE

8

Base unit consists of the following ICs as shown in Block Diagram (Base Unit) (P.7).

• DECT BBIC (Base Band IC): IC501

- Handling all the audio, signal and data processing needed in a US DECT base unit
- Controlling the US DECT specific physical layer and radio section (Burst Module Controller 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 Tranceiver (LNA Mixer IF Filter, Modulator/Demodulator, PLL, Vco)

• EEPROM: IC561

- Temporary operating parameters (for RF, etc.)

• FLASH MEMORY: IC541

- Voice Prompt (TAM) D/L Area
- ICM/OGM/MEMO Recording Area

• TAM Companion: IC201

- Voice data compression and decompression
- Speaker Amp

• Additionally,

- Power Supply Circuit (+4.0 V, +3.3 V, +2.5 V, +1.8 V output)
- Crystal Circuit (10.368 MHz)
- Telephone Line Interface Circuit

9

The power is supplied to the BBIC,TAM Companion,Power AMP,LCD module,EEPROM,Flash Memory,LED,LCD backlight from
AC Adaptor(+6.5V) as shown in Fig 1.
When power line failure, the power is supplied to BBIC,TAM companion,EEPROM from telephone line instead of AC Adaptor
through D138 and Q341.

• BBIC (IC501) 

• TAM Companion (IC201) 

AC adaptor 

→ F301 → D301→ IC301 → D353 → IC201 (VDDPA 3.2V)

• RF Power AMP (IC801) 

AC adaptor 

→ F301 → D301→ IC304 → Q608 → IC801 (VCC)

• EEPROM (IC561) 

• Flash memory (IC541)

AC adaptor 

→ F301 → D301→ IC301 → D311 → IC501 (BAT:CP_VOUT1) → IC541 (VDD 3.0V)

• LCD module

AC adaptor 

→ F301 → D301→ IC301 → D311 → IC501 (BAT:CP_VOUT1) → CN1 → LCD module (VDD 3.0V)

• LED

AC adaptor 

→ F301 → D301→ IC301 → D311 → IC501 (BAT:CP_VOUT1) → CN1 → LED (3.0V)

• LCD backlight

AC adaptor 

→ F301 → D301 → IC301→ CN2 → LCD backlight (3.5V)

<Fig.1>

10

• Bell signal detection
• CLIP signal detection
• ON/OFF hook and pulse dial circuit

In standby mode,Q111/Q115 is open to cut the DC Loop current and decrease the ring load.
When ringing voltage appears at the TIP and RING, AC ring voltages transferred as followings;
CLIP signal detection

TIP 

→ C181 → R182 → R185 → IC501(26)(BBIC-CIDINn)

RING 

→ C191 → R192 → R195 → IC501(27)(BBIC-CIDINp)

TIP 

→ C181 → R182 → C184 → R186 → C187 → IC501(30)(BBIC-RINGING)

When power line failure (Because this case is no power to IC501)
TIP 

→ C164 → D161(2) → D161(1) →  IC101(1:5) → R167 → RINGERP

RING 

← D161(3) ← D161(4) ← Q162(c:e) ← IC101(2:8) ← RINGERM

ON hook:
Q111/Q115 is open to cut the DC loop current and voice signal, caused by the following control:
Hook switch (between hook2-4 and hook2-6) is opened and IC501(29)(Hook CTRL) is Low, (and Q114 is open), then Q112 is
OFF,so Q111/115 is OPEN
OFF hook:
Q111/Q115 is ON to make the DC loop current and be possible to transfer voice signal, caused by the following control:
Hook switch (between hook2-4 and hook2-6) make and IC501(29)(Hook CTRL) is High. (and Q114 is open), then Q112 is ON.

The audio signal from Mic (for SP-phone and Corded Handset) is converted from Analog to digital in TAM companion IC(IC201),
then is transfered to BBIC(IC501) through PCM interface.
In BBIC(IC501), these data is converted to Analog, then send out tel line through tel line interface.
On the other hand, the audio signal from tel line is converted from Analog to digital in BBIC(IC501), then is transfered to TAM
companion IC(IC201) through PCM interface.
In TAM companion IC(IC201) ,these data is converted to Analog, then sound out from speaker.
Refer to the fig.2.

<Fig.2>

BBIC(IC501) inclueds the RF transceiver circuit. (LNA,Mixer, IF filter, modulator/Demodulator,PLL, VCO etc).
This RF transceiver is interfaced  with Power-AMP(IC801) and Antenna circuit.

During pulse dialling the hookswitch (Q3, Q4) is used to generate the pulses using the HOOK control signal, which is set high
during pulses. To force the line impedance low during the “pause” intervals between dial pulses, the PULSE_DIAL signal turns
on Q2.

11

SPEAKER

RECEIVER

MIC

CHARGE

CIRCUIT

Q4, Q9, R7Q4,

Q9,

R7

CHARGE

CONTACTS

CHARGE(+)

CHARGE(-)

CHARGE_CTRL

CHARGE

EEPROM

SCL

SDA

BATTERY

TERMINAL

D7

VBAT

J1

J2

1.8 V

Q2

1.8 V

LCD

CD

RESET

CSB

SDA

 SCL

CPU

Analog

Front

End

D/A

A/D

33

35

15

16

19

20

32

31

57

58

 36

13

43

42

63

54

55

66

ADPCM

Codec

Filter

DSP

Speech

Decoding

Speech

Encoding

BMC

Burst

Decoding

RF PA

ANT1

Burst

Encoding

RF

PLL

MOD/DEMOD

5

3

4

3

6

7

8

9

2

77

78

75

RXn

RXon

ANT1

DA801

RXp

TXp

TXn

Pon

PSEL

TXon

VDD-PADRY

9

10

XTAL

X1

10.368

MHz

BATTERY

44

ON SWITCH

KEYPAD

Charge

Pump

ROWS

COLUMNS

CP3.0V

CP4.0V

48, 49, 50, 51

22, 23, 24, 25, 26

BBIC

 56

LCD-BACK  LIGHT

KEY   LED

BELL  LED

52

68

73

74

80

LDO_CTRL

KX-TGA641 BLOCK DIA

GRAM (CORDLESS HANDSET)