Nickel-cadmium battery fast charger temperature control circuit

Rapid charging of nickel-cadmium batteries will cause temperature rise.
As shown in the figure, the nickel-cadmium battery quick charger temperature
control circuit can set and detect the battery temperature
to control the charging current.
    Icl~lC3 constitute the temperature control circuit , and 1C4
is the charging circuit. IC1 and IC2 are for temperature detection, and
RPi is adjusted so that the output voltage of IC1 is
slightly higher than the output voltage of IC2 by 50mV. In this way, before the temperature control is started, the potential of pin ③ of voltage comparator IC3 is higher than that of pin ②,
the output is high level, VD2 is cut off, and IC4 charges the battery with a constant current of about 1A. IC2 is attached to the surface of the battery being charged.
When the battery temperature rises to a certain temperature, that is, when the potential of pin ② is higher than the potential of pin ③, IC3 outputs low level, VD2 is turned on
, and the ADJ pin of IC4 has a low potential of about 0.7V. , the output is constant voltage, maintaining the low current charging mode, and the battery temperature also
decreases. In the same way, when the battery temperature drops to the previous temperature, constant current charging resumes.