Panasonic KX-TCD450RUM / KX-A145RUM / KX-TCD450RUT / KX-A145RUT Service Manual ▷ View online
21 BLOCK DIAGRAM (HANDSET)
31
CPU
IC1
IC10
BBIC
A/D
D/A
Analog
Front
End
Front
End
Speech
Encoding
Encoding
Speech
Decoding
Decoding
DSP
ADPCM
Codec
Filter
Codec
Filter
BMC
RF
Interface
Interface
MIC
EEPROM
IC3
SDA
SCL
64
65
5
6
SYRI
RSSI
SYEN
RXDA
TXDA
14
10
46
21
11
RF
Module
Module
ANT
BATTERY
TERMINAL
TERMINAL
TP3
TP4
CHARGE
CIRCUIT
CIRCUIT
CHARGE
CHARGE DETECT
SWITCHED
SUPPLY
SUPPLY
CHARGE
CONTACTS
CONTACTS
TP5
4.0V
VDDBAT
VDDLR
SWITCH
29
XTAL
10.368
MHz
KEYPAD
BACKLIT
KEYPAD LEDS
KEYPAD LEDS
COLUMNS
ROWS
LCD
ON SWITCH
36
25
32
34
35
79
80
26
KX-A145RUM/RUT BLOCK DIAGRAM (HANDSET)
INH/RS 67
CS/CE 63
DISDATA 86
EARPIECE
SPEAKER
40
39
47
15~19
51~53, 57, 58
24
Burst
Encoding
Encoding
Burst
Decoding
Decoding
+
TP6
D20
DISCLK 50
AMPLIFIER
IC4
43
Headset
JACK
SP_AMP
69
Flash
Memory
Memory
IC2
ADR 00~18
CE, OE, WR
DAT 00~07
Q7, Q8
Q1
X1
SP-PHONE LED
61
KX-TCD450RUM / KX-A145RUM / KX-TCD450R UT / KX-A145RUT
22 CIRCUIT OPERATION (HANDSET)
22.1. Outline
Handset consists of the following ICs as shown in BLOCK DIAGRAM (HANDSET) (P.61).
·
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 Module: IC10
−
−
−
−
PLL Oscillator
−
−
−
−
Detector
−
−
−
−
Compress/Expander
−
−
−
−
Amplifier for transmission and reception
·
Flash Memory: IC2
−
−
−
−
Program Code
·
EEPROM: IC3
−
−
−
−
Temporary operating parameters (for RF, etc)
22.2. Power Supply Circuit/Reset Circuit
Circuit Operation:
When power on the Handset, the voltage is as follows;
BATTERY(2.2 V ~ 2.6V: TP3)
→
+4V(4V)
→
IC10(6, 27), D20
→
IC1(35)
→
IC1(37, 22, 1, 84, 61) (2.65V)
The Reset signal generates IC1,C58 and 2.65V.
22.3. Charge Circuit
Circuit Operation:
When charging the handset on the Base Unit, the charge current is as follows;
DC+(5.5V ~ 6V)
→
D4
→
R43, R44
→
L4
→
CHARGE+(Base)
→
CHARGE+(Handset)
→
Q7
→
F1
→
BATTERY+ ... Battery
... BATTERY-
→
R14
→
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 Q7 of Handset.
Refer to Fig.101 in Power Supply Circuit (P.59).
22.4. 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) < 2.3V
The BBIC detects this level and "
" starts flashing and "battery alarm" starts ringing.
·
Power Down
Battery voltage: V(Batt) < 2.2V
The BBIC detects this level and power down.
22.5. Speakerphone and Headset Jack
The hands-free loudspeaker at SP+ and SP- is used to generate the ring alarm. IC4 is used to switch off the telephone
loudspeaker and is used to amplify the signal to drive the hands-free loudspeaker. They are selected using the SP_AMP line
from pin 69 of the BBIC. 2.5mm headset jack is also available.
loudspeaker and is used to amplify the signal to drive the hands-free loudspeaker. They are selected using the SP_AMP line
from pin 69 of the BBIC. 2.5mm headset jack is also available.
62
KX-TCD450RUM / KX-A145RUM / KX-TCD450R UT / KX-A145RUT
23 CIRCUIT OPERATION (CHARGER UNIT)
23.1. Power Supply Circuit
The power supply is as shown.
63
KX-TCD450RUM / KX-A145RUM / KX-TCD450R UT / KX-A145RUT
24 SIGNAL ROUTE
64
KX-TCD450RUM / KX-A145RUM / KX-TCD450R UT / KX-A145RUT
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