POWER THYRISTOR CONTROL DEVICE Russian patent published in 1997 - IPC

FIELD: electronic control devices. SUBSTANCE: control device has first voltage supply whose negative lead is connected to power thyristor cathode and positive lead, to additional transistor base through emitter-collector junction and to main transistor emitter through current-limiting resistor; main transistor base is connected to additional transistor emitter and its collector, to cutoff transistor base; positive lead of second voltage supply is connected to power thyristor cathode and negative lead, to collector of cutoff transistor whose base-collector junction is shorted out by first resistor and base-emitter junction, by diode whose anode is connected, in addition, to collectors of main and additional transistors; base-emitter junction of main transistor is shorted out by second resistor and limiting transistor base is connected to main transistor emitter through series-connected third and fourth resistors whose common point of connection is connected through capacitor to positive lead of first voltage supply; additional transistor base is connected to output of optocoupler-input relay unit having hysteresis characteristic. EFFECT: improved reliability of control. 1 dwg