
22
KX-TG6641B/KX-TG6643B/KX-TG6644B/KX-TG6645B/KX-TGA660B
4.8.
Behavior of Electric Power Failure
In case that the power from AC adaptor is lost and lose radio waves, BBIC (IC1) turns IC6 ON since handset presumes that
base unit's power is failed.
Base unit detects that power voltage of AC a5.5V is OFF at IC351, then turns Q351 ON.
It's possible to use the units during the power failure, supplying power to VBAT of base unit from battery of handset through IC6,
CHG terminal and Q351.
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.20)
The route for this is as follows: DC+pin of J1(+)
→
F1
→
R1
→
pad
→
Handset
→
CHARGE-pad
→
DC-pin of J1(-).
IC6
Handset
BATT+
BATT_
Base Unit
Q351
VBAT
IC351
VIN
VOUT
COUT
BBIC
IC1
R45
CHG-
CHG+
D1
R354
R355
R351
R352
3
VOUT
VIN
VSS
+5.5V
R1
TP1
TP2
J1
AC Adaptor
F1