Behavior Of Electric Power Failure; Circuit Operation (Charger Unit) - Panasonic KX-TG3711BXB Service Manual

KX-TG3711BX/KX-TG3712BX/KX-TG3719BX/KX-TGA371BX
4.9.

Behavior of Electric Power Failure

In case that the power from AC adaptor is lost and lose radio waves, BBIC (IC1) turns Q11 and Q10 ON since handset
presumes that base unit's power is failed.
Base unit detects that power voltage of AC adaptor +5.5V 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.
BATT+
BATT_
R45

4.10. 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)
AC Adaptor
The route for this is as follows: DC+pin of J1(+) → F1 → R1 → CHARGE+pad → Handset → CHARGE-pad → DC-pin of J1(-).
Handset
Q10
R11
Q12
R14
Q11
R6
R13
GND GND
71
BBIC
IC1
F1
(+)
J1
(-)
Base Unit
CHG+
Q351
R354
CHG-
R355
VOUT
R1
TP1 (CHARGE+pad)
TP2 (CHARGE- pad)
22
VBAT
+5.5V
IC351
R351
VIN
VSS
R352