Protective circuit for switching regulator

Abstract

Abstract PURPOSE: To protect switching transistor by the procedure in which by detecting the collector-emitter saturated voltage of transistor when it exceeds a predetermined value, the pulse width of high frequency pulse is eliminated by control circuit and electrification of transistor is shut off. CONSTITUTION: The Zener diode D z is connected through resistor in parallel to between the collector and emitter of the switching transistor 3, and when the collector and emitter saturated voltage of the transistor 3 exceeds the Zener voltage, the transistor 7 for detection is electrified and the pulse width of high frequency pulse is made zero by the control circuit 6, making the switching transistor 3 non- energized. Since this is a collector-emitter saturated voltage detection type, voltage applied to switching transistor which was so far not detected is high and thus protection is made possible in the region where current flowing in switching transistor is small. COPYRIGHT: (C)1979,JPO&Japio

Inventors

• 👤 Takehisa Sato

Bibliographic Details