Charge Circuit; Battery Low/Power Down Detector; Speakerphone; Circuit Operation (Charger Unit) - Panasonic PRL Series Service Manual

4.8.3.

Charge Circuit

Circuit Operation:
When charging the handset on the Base Unit, the charge current is as follows;
DCP(5.5 V)  F301  R371  R372  D362  CHARGE+(Base)  CHARGE+(Handset)  R8  Q3  F1 
BATTERY+... Battery...
BATTERY-  R45  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 Q9 of Handset.
Refer to Fig.101 in Power Supply Circuit/Reset Circuit (P.14).
CHG +
CHG -
GND
4.8.4.

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 "
• Power Down
Battery voltage: V(Batt) 2.0 V ± 50 mV
The BBIC detects this level and power down.
4.8.5.

Speakerphone

The hands-free loudspeaker at SP+ and SP- is used to generate the ring alarm.
4.9.

Circuit Operation (Charger Unit)

Charge control is executed at handset side so that the operation when using charger is also controlled by handset.
Refer to Circuit Operation (Handset) (P.22)
AC Adaptor
The route for this is as follows: DC+pin of J1(+)  CHARGE+pad  Handset  CHARGE-pad  DC-pin of J1(-).
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Q2
C27
R2
R8
R4 Q4
47K
R6
10K
Q9
GND
R7
100K
" starts flashing.
J1
KX-PRL260/KX-PRL262/KX-PRD260/KX-PRD262/KX-PRLA20
Q3
BATT +
BATTERY
2CELL
BATT -
R45
GND
CHG CTRL (33)
CHG DET (34)
23
BBIC
IC1
TP1
TP2