| 摘要 |
<p>A bipolar junction transistor (BJT) (Q1) used as a controlled rectifier (CR) that is driven and controlled by an electronic circuit, such that when (in a first mode of operation) the collector- emitter voltage (VCE) is above an offset voltage (vceos) the circuit drives the base of sr bjt (Q1) with a base current proportional to the difference between vce and vceos, turning the cr bjt (Q1) on with a base current proportional to the collector current w hen the vce of the CR BJT falls below vceos the drive circuit turns on a second transistor coupled between the base and collector of cr bjt (Q1) to turn the CR BJT rapidly off and maintains it in the off stat as collector voltage reverses. When the vce of the CR BJT (Q1) exceeds a threshold voltage above the normal conduction vce range, the control circuit increases the base drive current to accelerate the CR BJT (Q1) turn on process. A second mode of operation occurs in the presence of an 'off' drive command to the cr, which turns the CR off when the collector voltage is above the emittar voltage. Turn off of the cr is now accomplished with a third transistor coupled between the base and emitter of the CR BJT (Q1).</p> |
