Panasonic KX-FLC418RU Service Manual ▷ View online
53
KX-FLC418RU
6.16. Cordless Handset Section
6.16.1. Cordless Handset Block Diagram
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
CP3.0 V
CP4.0 V
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
CORDLESS HANDSET BLOCK DIAGRAM
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KX-FLC418RU
6.16.2. Cordless Handset Circuit Operation
6.16.2.1. Outline
Cordless handset consists of the following ICs as shown in Cordless Handset Block Diagram (P.53).
• 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
- 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.)
6.16.2.2. 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+)
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.
6.16.2.3. Charge Circuit
Circuit Operation:
When charging the cordless handset on the Base Unit, the charge current is as follows;
DC+(6.5 V)
DC+(6.5 V)
→ D1 → R56 → R55 → D22 → CHARGE+(Base) → CHARGE+(Handset) → Q4 → D7→ F1 → BATTERY+...
Battery...
BATTERY-
BATTERY-
→ R45 → GND → CHARGE-(Handset)→ CHARGE-(Base) → 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.
The charge current is controlled by switching Q9 of cordless handset.
6.16.2.4. 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;
The detected voltage is as follows;
• Battery Low
Battery voltage: V(Batt) 2.25V ± 50mV
The BBIC detects this level and "
" starts flashing.
• Power Down
Battery voltage: V(Batt) 2.0V ± 50mV
The BBIC detects this level and power down.
The BBIC detects this level and power down.
6.16.2.5. Speakerphone
The hands-free loudspeaker at SP+ and SP- is used to generate the ring alarm.
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KX-FLC418RU
6.16.3. Circuit Operation (Charger Unit)
6.16.3.1. Power Supply Circuit
The power supply is as shown.
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KX-FLC418RU
6.17. HVPS (High Voltage Power Supply) Section
6.17.1. HVPS Specification
As for the developing voltage, the DC voltage and AC voltage are overlapped and output from an output terminal.
There is one terminal for transcription output and + and - are switched to be output.
There is one terminal for transcription output and + and - are switched to be output.
Charge (CHG)
Grid
Developing DC
Transfer (TRA-)
Transfer (TRA+)
Output Characteristics Constant current
Constant voltage
Constant voltage
Constant current
(Variable)
(Variable)
Constant voltage
Nominal Output Voltage 4.25KV
475±10V
220V±15V
100M
Ω
(-800V)
800V±100V
Nominal Output Current 180±15
µA
180
µA
300M
Ω
-8
µA±1µA
(-4
µA~-25µA)
PWM 58%
1000M
Ω
(0.8
µA)
Load Range
(19.4M
Ω)
100M
Ω~2000MΩ
62.5M
Ω~312MΩ
10M
Ω~1000MΩ
Constant Current
Range
Range
4.1~4.6KV
-500V~-2500V
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