Power switching circuit having a Darlington connected transistor pair
AssigneeLucas Industries Limited
InventorOwen Edgar Wright
Life of this patent
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Abstract
A switching circuit has an output transistor between an input and an output conductor, and a drive transistor, the transistors being Darlington-connected. A transformer has one winding in the collector circuit of the drive transistor and another winding across the base-emitter junction of the output transistor, the windings being arranged so that a falling collector current to the drive transistor induces a reverse bias current in the base-emitter junction of the output transistor.
Claims6
A power switching circuit comprising a first supply conductor, a first output conductor, an output transistor having its collector connected to one conductor and its emitter connected to the other conductor, a drive transistor having its emitter connected to the base of the output transistor and its base connected to a control circuit and a transformer having one winding connecting the collector of the drive transistor to said one conductor and another winding connecting the emitter of the drive transistor to the emitter of the output transistor, the transformer being wound so that falling current in the collector of the drive transistor induces reverse bias current in the base-emitter junction of the output transistor.
Dependencies are inferred from the claim text.