DOWNLOAD Panasonic KX-TG6451RUT / KX-TGA641RUT Service Manual ↓ Size: 3.14 MB | Pages: 94 in PDF or view online for FREE

Model
KX-TG6451RUT KX-TGA641RUT
Pages
94
Size
3.14 MB
Type
PDF
Document
Service Manual
Brand
Device
Telephone / DIGITAL CORDLESS PHONE
File
kx-tg6451rut-kx-tga641rut.pdf
Date

Panasonic KX-TG6451RUT / KX-TGA641RUT Service Manual ▷ View online

11
KX-TG6451RUT/KX-TGA641RUT
4.3.
Block Diagram (Cordless Handset)
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
IC801
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
IC1
IC3
 56
LCD-BACK  LIGHT
KEY   LED
BELL  LED
52
68
73
74
80
LDO_CTRL
KX-TGA641 BLOCK DIA
GRAM (CORDLESS HANDSET)
12
KX-TG6451RUT/KX-TGA641RUT
4.4.
Circuit Operation (Cordless Handset)
4.4.1.
Outline
Cordless Handset consists of the following ICs as shown in Block Diagram (Cordless Handset) (P.11).
• 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 Power Amp.)
- PLL Oscillator
- Detector
- Compress/Expander
- Reception
• RF Power Amp: IC801
- Amplifier for transmission
• EEPROM: IC3
- Temporary operating parameters (for RF, etc.)
4.4.2.
Power Supply Circuit/Reset Circuit
Circuit Operation:
When power on the Cordless Handset, the voltage is as follows;
BATTERY(2.2 V ~ 2.6 V: BATT+) 
→ F1 → Q2 (1.8 V), IC1-43pin (2.5V)
The Reset signal generates IC1 (61 pin) and 1.8 V.
4.4.3.
Charge Circuit
Circuit Operation:
When charging the Cordless Handset on the Charger Unit, the charge current is as follows;
DC+(6.5 V) 
→ F1 → R1 → CHARGE+(Charger) → CHARGE+(Cordless Handset) → L4 → Q4 → D7→ F1 → BATTERY+... Bat-
tery... 
BATTERY- 
→ L8 → R45 → GND → L5 → CHARGE-(Cordless Handset)→ CHARGE-(Charger) → GND → DC-(GND)
In this way, the BBIC on Cordless Handset detects the fact that the battery is charged.
The charge current is controlled by switching Q9 of Cordless Handset.
4.4.4.
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.
4.4.5.
Speakerphone
The hands-free loudspeaker at SP+ and SP- is used to generate the ring alarm.
13
KX-TG6451RUT/KX-TGA641RUT
4.5.
Circuit Operation (Charger Unit)
4.5.1.
Power Supply Circuit
The power supply is as shown.
14
KX-TG6451RUT/KX-TGA641RUT
4.6.
Signal Route
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