Panasonic KX-F900 Service Manual page 183

KX-F900
(6) ReseUPowe_ uow.luattery LowilD
When the battery is installed in the portable hm}dset, the reset circuit consisting of R289, C255, and Q204
functions, inputting a reset signal to the CPU. This ensures that the unit will operate normally without the user's
needing to switch the power off and on. When the voltage from the batteries drops to 3.5 V, 3.5 V voltage
detector IC204 operates and inputs a battery low signal to the CPU. This causes the battery low LED to flash
on and off. If voltage continues to drop and reaches 3.2 V, 3.2 V voltage detector IC206 operates and outputs
a power down signal to the CPU. This causes power to be cut off automatically and prevents the battery from
over discharging. Q201 is a charge detector that informs the CPU whether or not the portable handset is
currently being charged. During charging, ID data is sent from the base unit. Q202 receives this ID data and
sends it to the CPU.
Circuit Diagram
[]
R289 C255
D201 'W_,_ I I r_204_:
R286 IC206 _ I "' :_
Battery_e_e [ _ I--- "L £ , R208 _>Q
Q20_ R205
R201 "_ _2_ R206
'_' .1_
R202 -£-
C204 D213
@
@
RESET
Powerdown
Bakery low
Charge
ID
183