A resonant converter having a primary side for receiving a DC voltage from an input power supply and a secondary side for providing a DC output voltage, the resonant converter comprising: a first converter switch; a second converter switch coupled in series with the first converter switch, wherein the first and second converter switches (410, 312) are provided across the input power supply; a switching transformer with a primary side winding and a secondary side winding, wherein the primary side winding is coupled in parallel with the second converter switch, the switching transformer configured to transfer energy from the primary side winding to the secondary side winding of the switching transformer; a resonant tank associated with the primary side winding of the switching transformer; a signalling transformer with a primary side winding and a secondary side winding, wherein the secondary side winding of the signalling transformer is connected to the secondary side winding of the switching transformer and wherein the secondary side winding of the signalling transformer is configured to transfer a signal from the secondary side winding of the signalling transformer to the primary side winding of the signalling transformer; and a primary side controller configured to control the first and second converter switches (410, 312) in response to the signal received at the primary side winding of the signalling transformer, wherein the switching transformer has a first secondary side winding and a second secondary side winding and the signalling transformer has a first secondary side winding and a second secondary side winding, wherein a first terminal of the first secondary side winding of the switching transformer is coupled to a first terminal of the second secondary side winding of the switching transformer and to ground, a second terminal of the first secondary side winding of the switching transformer is coupled to a first terminal of the first secondary side winding of the signalling transformer, a second terminal of the second secondary side winding of the switching transformer is coupled to a first terminal of the second secondary side winding of the signalling transformer, wherein a second terminal of the first secondary side winding of the signalling transformer is coupled to a load terminal and a second terminal of the second secondary side winding of the signalling transformer is coupled to the load terminal, wherein the load terminal is respectively coupled to the first and second secondary side windings (438a, 438b) of the signalling transformer by first and second rectifiers (442, 444) and wherein the polarity of the first rectifier is the same as the polarity of the second rectifier. a first converter switch; a second converter switch coupled in series with the first converter switch, wherein the first and second converter switches (410, 312) are provided across the input power supply; a switching transformer with a primary side winding and a secondary side winding, wherein the primary side winding is coupled in parallel with the second converter switch, the switching transformer configured to transfer energy from the primary side winding to the secondary side winding of the switching transformer; a resonant tank associated with the primary side winding of the switching transformer; a signalling transformer with a primary side winding and a secondary side winding, wherein the secondary side winding of the signalling transformer is connected to the secondary side winding of the switching transformer and wherein the secondary side winding of the signalling transformer is configured to transfer a signal from the secondary side winding of the signalling transformer to the primary side winding of the signalling transformer; and a primary side controller configured to control the first and second converter switches (410, 312) in response to the signal received at the primary side winding of the signalling transformer, wherein the switching transformer has a first secondary side winding and a second secondary side winding and the signalling transformer has a first secondary side winding and a second secondary side winding, wherein a first terminal of the first secondary side winding of the switching transformer is coupled to a first terminal of the second secondary side winding of the switching transformer and to ground, a second terminal of the first secondary side winding of the switching transformer is coupled to a first terminal of the first secondary side winding of the signalling transformer, a second terminal of the second secondary side winding of the switching transformer is coupled to a first terminal of the second secondary side winding of the signalling transformer, wherein a second terminal of the first secondary side winding of the signalling transformer is coupled to a load terminal and a second terminal of the second secondary side winding of the signalling transformer is coupled to the load terminal, wherein the load terminal is respectively coupled to the first and second secondary side windings (438a, 438b) of the signalling transformer by first and second rectifiers (442, 444) and wherein the polarity of the first rectifier is the same as the polarity of the second rectifier.