Protecting overcurrent of power-switching element in switching power supply

Abstract

Abstract PURPOSE: To protect a power-switching element by immediately turning it off when an overcurrent flowing through the power switching element exceeds a specified value. CONSTITUTION: A gate 13 is inserted between the output terminal of a pulse-width modulator 3 and the input terminal 4 which generates driving pulses to be applied to be applied to a power-switching element 5. An overcurrent signal is sensed by a current transformer CT, and the output is generated from a comparator 6 when the overcurrent signal exceeds a specified value determined by a reference voltage. The output sets a latch 12. The gate 13 is turned off at an instant the latch 12 is set, and the output pulses from the pulse-width modulator 3 is cut off by the gate 13. The driving pulses from the driver 4 becomes zero, and the power-switching element is turned off. COPYRIGHT: (C)1980,JPO&Japio

Inventors

• 👤 Ryoji Imazeki
• 👤 Masayuki Hattori
• 👤 Shigeo Nakamura

Bibliographic Details