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- Temporary operating parameters (for RF, etc.)
19.2. Power Supply Circuit/Reset Circuit
Circuit Operation:
When power on the Handset, the voltage is as follows;
BATTERY(2.2 V ~ 2.6V: J1)
The Reset signal generates IC1 (78) and 1.8V.
19.3. Charge Circuit
Circuit Operation:
When charging the handset on the Base Unit, the charge current is as follows;
DC+(5.5V ~ 6V)
D1
F1
BATTERY+ ... Battery ... BATTERY-
(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 of Handset.
Refer to Fig.101 in
Power Supply Circuit
19.4. 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)
The BBIC detects this level and "
- Power Down
Battery voltage: V(Batt)
The BBIC detects this level and power down.
19.5. Speakerphone and Headset Jack
The hands-free loudspeaker at SP+ and SP- is used to generate the ring alarm. IC2 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 70 of the BBIC. 2.5mm headset
jack is also available.
20. CIRCUIT OPERATION (CHARGER UNIT)
L1, D1, Q2 (1.8V)
R4, R5
CHARGE+(Base)
R43
().
2.3V ± 50mV
2.2V ± 50mV
Q3 (2.7V)
Q1 (4.0V)
CHARGE+(Handset)
GND
CHARGE-(Handset)
" starts flashing.
43
L4
Q4
D7
CHARGE-
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