An AC/DC PFC converter, comprising: a rectifier, an AC input for providing an input voltage and an input current to the input of the rectifier, wherein the rectifier is arranged for rectifying the input voltage to obtain a rectified input voltage; a half bridge inverter for receiving the rectified input voltage and comprising a first switch and a second switch, wherein a first output is defined from a node between the switches; an LLC circuit (20,24,26,27) coupled to the first output and having a second output for supplying a converter output voltage and current, wherein a voltage across a capacitor of the LLC circuit is provided as an electrical feedback parameter, wherein the electrical feedback parameter is representative of the input current, wherein the capacitor is arranged for acting as a resonance capacitor; and a control circuit configured to generate a gate drive signal for controlling the switching of the first switch and the second switch in dependence on the electrical feedback parameter, 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 outer control loop configured to set a threshold level for the electrical feedback parameter proportional to an integration of an output voltage error (Δvo) and multiplication by the rectified voltage without measurement of the input current, and an inner control loop for comparing the electrical feedback parameter with the threshold to derive the gate drive signal and to provide power factor correction. a rectifier, an AC input for providing an input voltage and an input current to the input of the rectifier, wherein the rectifier is arranged for rectifying the input voltage to obtain a rectified input voltage; a half bridge inverter for receiving the rectified input voltage and comprising a first switch and a second switch, wherein a first output is defined from a node between the switches; an LLC circuit (20,24,26,27) coupled to the first output and having a second output for supplying a converter output voltage and current, wherein a voltage across a capacitor of the LLC circuit is provided as an electrical feedback parameter, wherein the electrical feedback parameter is representative of the input current, wherein the capacitor is arranged for acting as a resonance capacitor; and a control circuit configured to generate a gate drive signal for controlling the switching of the first switch and the second switch in dependence on the electrical feedback parameter, 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 outer control loop configured to set a threshold level for the electrical feedback parameter proportional to an integration of an output voltage error (Δvo) and multiplication by the rectified voltage without measurement of the input current, and an inner control loop for comparing the electrical feedback parameter with the threshold to derive the gate drive signal and to provide power factor correction.