1. An AC/DC PFC converter, comprising:an AC input;
a half bridge inverter comprising a first switch and a second switch, wherein a first output is defined from a node between the switches;
a self-oscillating resonant circuit coupled to the first output and having a second output for providing a converter output voltage or current and wherein the self-oscillating resonant circuit is arranged for providing an electrical feedback parameter; and
a self-oscillating control circuit for generating a gate drive signal for controlling the switching of the first switch and second switch in dependence on the electrical feedback parameter in order to control the converter output voltage or current, wherein a high gate drive signal turns on one switch and turns off the other switch and a low gate drive signal turns off the one switch and turns on the other switch, wherein the control circuit comprises:
an input for receiving a threshold value for the electrical feedback parameter;
an output circuit for generating the gate drive signal based on a comparison of the electrical feedback parameter with the threshold in a first mode; and
a timeout circuit arranged to provide a restart signal for restarting switching of the gate drive in a second mode wherein the electrical feedback parameter fails to achieve the desired threshold.