Schaltnetzteil mit Überstromschutzschaltung

摘要

A switching power supply having an overcurrent protective circuit which includes a detection resistor for detecting the primary current of a transformer to produce a detected voltage, a reference voltage circuit for producing a reference voltage, and an amplifier. The amplifier produces an overcurrent protective signal when the detected voltage exceeds the reference voltage, and supplies the overcurrent protective signal to the control terminal of a switching device which switches the primary current so that a drive signal for the switching device is decreased when an overcurrent of the secondary current occurs. The overcurrent is limited to a value equal to or less than the rated current of the switching power supply without an instantaneous interruption of the power.