Battery protection circuit

专利名称：Battery protection circuit发明人：John J. Collins申请号：US06/145900申请日：19800502公开号：US04342953A公开日：19820803

摘要：A battery protection circuit particularly for portable lamps employing

rechargeable batteries is provided to prevent overdischarge of the batteries and includesa bulb drive transistor connecting a bulb across the battery with a switch interposedbetween one side of the battery and the bulb, a voltage sensing resistor connected toone side of the switch, a regenerative switch connected between the sensing resistor andthe other side of the battery, and the regenerative switch including an output terminalconnected by a base resistor to the base of the drive transistor. The regenerative switchincludes a pair of transistors connected and cooperating such that when one of thetransistors is turned on, the other is caused to be turned on, the transistors, further,maintaining each other on. As the dropout voltage of the battery is approached, the basedrive of the drive transistor decreases which causes the bulb to become dim to therebywarn of the discharged state of the battery. At the dropout voltage, the voltage acrossthe sensing resistor, which is substantially in parallel with the base-emitter junction ofone of the switch transistors, is reduced to a level which is not sufficient to maintain thesensing transistor on whereby the switch transistors are turned off, resulting in the turn-off of the drive transistor so that the battery is protected from overdischarge.

申请人：NICHOLL BROTHERS, INC.

代理机构：Fishburn, Gold and Litman

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