Overload protection circuit for network supply stage

摘要

The circuit responds to an overcurrent at the output of the network supply stage, or a short-circuit at the pulse width modulator control device for the switching transistor within the latter. The fault current is detailed in the voltage drop (Ua) across a current sensing resistor (Rsense), coupled to a peak value rectifier (VC) providing a voltage profile (Up) compared with a reference voltage for automatic cut-out of the control device after a timed delay.Pref. cut-out is effected via an electronic switch (E5) activated via a delay element (V2) coupled to the output of the voltage comparator.