17 CIRCUIT OPERATION (HANDSET)
17.1. Outline
Handset consists ofthe following ICs as shown in
BLOCK DIAGRAM (HANDSET)
(P.51).
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•
•
•
DECT BBIC (
B
ase
B
and IC): IC1
−
−
−
−
All data signals (forming/analyzing ACK or CMD signal)
−
−
−
−
All interfaces (ex: Key, Detector Circuit, Charge, DC/DC Converter, EEPROM, LCD)
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•
•
•
RF Module: CN6
−
−
−
−
PLL Oscillator
−
−
−
−
Detector
−
−
−
−
Compress/Expander
−
−
−
−
Amplifier for transmission and reception
•
•
•
•
EEPROM: IC3
−
−
−
−
Temporary operating parameters (for RF, etc.)
17.2. Power Supply Circuit/Reset Circuit
Circuit Operation:
When power on the Handset, the voltage is as follows;
BATTERY(2.2 V ~ 2.6 V: J1)
→
L1, D1
→
Q2 (1.8 V), Q3 (2.5 V), Q1 (3.3 V)
The Reset signal generates IC1 (53 pin) and 1.8 V.
17.3. Charge Circuit
Circuit Operation:
When charging the handset on the Base Unit, the charge current is as follows;
DC+(5.5V ~ 6V)
→
D1
→
R4, R5
→
(Base)
→
(Handset)
→
L4
→
Q4
→
D7
→
F1
→
...
Battery... BATTERY-
→
R43
→
GND
→
L5
→
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 Q5 ofHandset.
Refer to Fig.101 in
Power Supply Circuit
(P.49).
17.4. 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;
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•
•
•
Battery Low
Battery voltage: V (Batt)
2.25V ± 50mV
The BBIC detects this level and “
” starts flashing.
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•
•
•
Power Down
Battery voltage: V (Batt)
2.0V ± 50mV
The BBIC detects this level and power down.
Refer to
Check Point (Handset)
(P.37).
17.5. Speakerphone
The hands-free loudspeaker at SP+ and SP- works as a ringer/alarm as well.
Refer to
Troubleshooting for Speakerphone (Handset)
(P.40).
52
KX-TG1283BXS / KX-TG1283B XT / KX-TCA122CXS / KX-TCA122CXT / KX-TCA121CXS / KX-TCA121CXT
Содержание KX-TG1283BXS
Страница 54: ...19 SIGNAL ROUTE 54 KX TG1283BXS KX TG1283BXT KX TCA122CXS KX TCA122CXT KX TCA121CXS KX TCA121CXT ...
Страница 55: ...55 KX TG1283BXS KX TG1283BXT KX TCA122CXS KX TCA122CXT KX TCA121CXS KX TCA121CXT ...
Страница 64: ...22 2 Handset 64 KX TG1283BXS KX TG1283BXT KX TCA122CXS KX TCA122CXT KX TCA121CXS KX TCA121CXT ...
Страница 76: ...27 2 KX TCA121CXS CXT 76 KX TG1283BXS KX TG1283BXT KX TCA122CXS KX TCA122CXT KX TCA121CXS KX TCA121CXT ...
Страница 78: ...28 3 Charger Unit 78 KX TG1283BXS KX TG1283BXT KX TCA122CXS KX TCA122CXT KX TCA121CXS KX TCA121CXT ...
Страница 89: ...Memo 89 KX TG1283BXS KX TG1283BXT KX TCA122CXS KX TCA122CXT KX TCA121CXS KX TCA121CXT ...