H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
H03K17/08—Modifications for protecting switching circuit against overcurrent or overvoltage
H03K17/082—Modifications for protecting switching circuit against overcurrent or overvoltage by feedback from the output to the control circuit
H03K17/0826—Modifications for protecting switching circuit against overcurrent or overvoltage by feedback from the output to the control circuit in bipolar transistor switches