Patent ID: 6597210
Filing Date: 2003-07-22
Classification: H02M,H03K,Y02B

Abstract:
A circuit for driving a bipolar junction transistor (BJT) used as a controlled rectifier (CR), comprising:a mode signal input; a drive circuit coupled to said mode signal input and having an input adapted for coupling to the collector and emitter of a BJT CR and an output adapted for coupling to the base of that BJT CR, said drive circuit including a sensing pathway for sensing the collector to emitter voltage (VCE) of that BJT CR and being configured to produce a CR BJT base drive current (IB) at said output and to operate in at least a first and a second mode of operation based on the state of a signal at said mode signal input; wherein in said first mode, said drive circuit senses VCE and generates, when the sensed VCE is greater than an offset value, a positive base drive current that is at least in part proportional to the sensed VCE minus said offset value, and wherein in said second mode, said drive circuit produces a base drive current to turn-off that BJT CR.