Switching circuit for battery charger - with converter, control unit and memory storing voltages from comparator with two reference levels

摘要

The switching circuit is for a battery charger, which supplies current to the battery via a switch controlling the supply and a converter. The control unit of the circuit opens the switch on the basis of a voltage derived from the battery. The switch is opened via a relay. The voltage derived from the battery is compared with one reference voltage (17) and then with a higher second reference voltage. The circuit contains a flip-flop (25), which is switched to one state by the output voltage of one section of the comparator (13) when the derived voltage is lower than the first reference voltage. It is switched to the second stage (18) if the derived voltage is higher than the second reference voltage. The last state is maintained when the derived voltage lies between the two reference voltages. Both input and output circuits contain Zener diodes (20,38).