Matsushita Electric KX-TCD952NLB, Service Manual

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11.1.11. MAIN 3V REGULATOR (SEE Fig. 29)
The BBIC measures the battery voltage on pins 58 using an internal ADC. If the battery voltage
is below 3.36 V, TC3 is switched to power off mode. R7 and C5 provide a reset pulse (TP84)
used for resetting the BBIC when power on. The +3 V supply (TP10) is fed to the BBIC, Flash
PROM, EEPROM, and Display Driver.
11.1.12. BATTERY CHARGING CIRCUIT (SEE Fig. 29)
The charge circuit is designed to operate with a constant current charger in the base. L1, L2, D2
and D4 protect against electro-static discharge (ESD). The charging current from the base is
turned on and off by T1 using a control signal from the BBIC (pin 39, TP6) via T2. R3 provides
initial current in the event of a totally flat battery, and D6 protects against the high voltage
present on the charge contacts if there is no battery in the handset. R4 and R5 provide a signal
for the BBIC to detect (pin 40) that the handset had been placed on the base charger. If the
handset is off, it will be switched on, and charging will start.
Circuit Diagram
12. ADJUSTMENT (BASE UNIT)
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