System to protect switch mode DC/DC converters against overload current

摘要

A method and circuit arrangement for sensing the output current in a switch mode power converter in order to provide protection arrangements which are responsive to overload or short circuit conditions. In a switch mode power converter including an inductor for providing output current to a load circuit, the inductor having an inherent resistance, a filter circuit is coupled to both the first terminal of the inductor and to the second terminal of the inductor. The filter circuit provides the DC component of the voltage across the inherent resistance of the inductor to an error amplifier. The error amplifier provides an output signal representing the output current, and the output signal is used to adjust an operating parameter of the switching circuit, e.g. duty cycle.