23
KX-TG6841B/KX-TG6842B/KX-TG6843B/KX-TG6844B/KX-TG6845B/KX-TG6873B/KX-TGA680B
4.8.
Behavior of Electric Power Failure
In case that the power from AC adaptor is lost and lose radio waves, BBIC (IC1) turns Q11 ON since handset presumes that
base unit's power is falied.
Base unit detects that power voltage of AC a5.5V is OFF, 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
Q10, 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.21)
The route for this is as follows: DC+pin of J1(+)
→
pad
→
Handset
→
CHARGE-pad
→
DC-pin of J1(-).
Handset
BATT+
BATT_
Base Unit
Q351
VBAT
Power Supply
at AC failure
(Q10,Q11,Q12)
BBIC
IC1
R45
CHG-
CHG+
R351
R352
3
Power Down
DET
(Q352,Q353)
+5.5V
TP1
TP2
J1
AC Adaptor