Protection circuit for switched-mode power supply circuit

Abstract

Abstract PURPOSE: To prevent a switching element from being broken down by an overcurrent, by changing the duty factor of switching pulses. CONSTITUTION: A resistor 14 is provided to detect a voltage corresponding to the current flowing through the switching element 13. A monostable multivibrator MM is shifted from a stable state to an unstable on when said current has exceeded a prescribed level. The duty factor of the switching pulses P5 to be supplied to the switching element 13 is changed on the basis of a voltage, which varies with time and which is produced by the time constant circuit CR of the monostable multivibrator when it is shifted to the unstable state. The switching element is thus protected from the overcurrent due to the short circuit of a load or the like. COPYRIGHT: (C)1980,JPO&Japio

Inventors

• 👤 Tomoaki Uchida

Bibliographic Details