초록 ▼

A battery charging circuit is provided with a thermally controlled cut-off switch whose normally closed contacts are in series with the main terminals of a thyristor. The thyristor is switched ON on commencement of battery charging by the charging of a capacitor C1, which remains charged even when t

A battery charging circuit is provided with a thermally controlled cut-off switch whose normally closed contacts are in series with the main terminals of a thyristor. The thyristor is switched ON on commencement of battery charging by the charging of a capacitor C1, which remains charged even when the contacts of the cut-off switch open as a result of the battery temperature rising upon completion of charging. Consequently, the thyristor remains latched OFF by the capacitor even when the contacts of the cut-off switch close, and can only be turned ON again by disconnecting the battery or power supply, disconnection of the battery or power supply causing capacitor C1 to discharge through a charge maintenance by-pass circuit connected in parallel with the thermal switch and thyristor.

대표청구항 ▼

In a battery charging circuit which includes a thermal cut-off switch arranged to open in order to cut-off a main charging current from a power supply to a rechargeable battery when a temperature sensed by the switch exceeds a predetermined temperature, the improvement comprising: a semiconductor sw

In a battery charging circuit which includes a thermal cut-off switch arranged to open in order to cut-off a main charging current from a power supply to a rechargeable battery when a temperature sensed by the switch exceeds a predetermined temperature, the improvement comprising: a semiconductor switching element connected in series between the switch and the power supply; means including a switch by-pass resistor circuit connected in parallel to the thermal cut-off switch and semiconductor switching element for providing a reduced charging current to the battery when the main changing current is interrupted because the thermal cut-off switch has opened; and means including a latch circuit for preventing said semiconductor switching element from conducting said main charging current to the switch after the switch has closed until the main charging current and reduced charging current are both interrupted, wherein said latch circuit comprises a capacitor connected in parallel to said semiconductor switching element between said switch and said power supply, and also between said switch and a trigger gate of the semiconductor switching element, said capacitor thereby being arranged to charge upon commencement of battery charging in order to switch ON said switching element before said switch has opened, and means for preventing said capacitor from discharging and thereby latching the switching element in an OFF state after the switch has opened irrespective of the state of the thermal cut-off switch, until said interruption of both the main and reduced charging currents.