METHOD AND APPARATUS FOR DETERMINING THE CONTROL ELECTRODE TO CATHODE JUNCTION VOLTAGE OF A CONTROL TURN-OFF SEMICONDUCTOR DEVICE AND USE OF SUCH DETERMINED VOLTAGE IN THE CONTROL OF THE DEVICE

摘要

METHOD AND APPARATUS FOR DETERMINING THE CONTROL ELECTRODE TO CATHODE JUNCTION VOLTAGE OF A CONTROL TURN-OFF SEMICONDUCTOR DEVICE AND USE OF SUCH DETERMINED VOLTAGE IN THE CONTROL OF THE DEVICE An apparatus and method relative to the operating of a control turn-off semiconductor device provide for determining the actual control electrode to cathode voltage upon the application of a turn-off control signal by adjusting the apparent value of that voltage by a value representing the voltage drop due to inductance in lead lines. The thusly adjusted value is employed to develop an output signal which indicates that the device has been turned off. In a further embodiment, the output signal may also be employed to reduce the value of the control signal from a first, relatively high value to a second, relatively low value.