A half bridge resonant converter, comprising: - a pair of DC voltage lines comprising a high voltage line and a low voltage line; - a half bridge inverter comprising a high side switch and a low side switch in series between the high voltage line and the low voltage line, wherein an output of the half bridge inverter is defined from a node between the high side switch and the low side switch; - a resonant circuit coupled to the output of the half bridge inverter via a series capacitor; - a first generating circuit for generating a first supply voltage from the high voltage line and from the voltage at the node wherein the first generating circuit comprises: - a first input for receiving a voltage between the node and the resonant circuit; - a charge pump circuit for converting an AC voltage at the first input into a DC voltage and storing it on a first output capacitor (Co) as an output of the first generating circuit at the first supply voltage; and - a supply transistor between the high voltage line and the output of the first generating circuit for charging the output capacitor (Co) before the start-of-oscillation occurs; - a second generating circuit for generating a second supply voltage from the low voltage line and from the voltage at the node; - a first control circuit for generating a gate drive signal for controlling the switching of the high side switch in dependence on an electrical feedback parameter, wherein the first control circuit has as its reference voltage supply the voltage at the node and the first supply voltage greater than the voltage at the node; and - a second control circuit for generating a gate drive signal for controlling the switching of the low side switch in dependence on the electrical feedback parameter, wherein the second control circuit has as its reference voltage supply the low voltage line and the second supply voltage greater than the voltage at the low voltage line. - a pair of DC voltage lines comprising a high voltage line and a low voltage line; - a half bridge inverter comprising a high side switch and a low side switch in series between the high voltage line and the low voltage line, wherein an output of the half bridge inverter is defined from a node between the high side switch and the low side switch; - a resonant circuit coupled to the output of the half bridge inverter via a series capacitor; - a first generating circuit for generating a first supply voltage from the high voltage line and from the voltage at the node wherein the first generating circuit comprises: - a first input for receiving a voltage between the node and the resonant circuit; - a charge pump circuit for converting an AC voltage at the first input into a DC voltage and storing it on a first output capacitor (Co) as an output of the first generating circuit at the first supply voltage; and - a supply transistor between the high voltage line and the output of the first generating circuit for charging the output capacitor (Co) before the start-of-oscillation occurs; - a second generating circuit for generating a second supply voltage from the low voltage line and from the voltage at the node; - a first control circuit for generating a gate drive signal for controlling the switching of the high side switch in dependence on an electrical feedback parameter, wherein the first control circuit has as its reference voltage supply the voltage at the node and the first supply voltage greater than the voltage at the node; and - a second control circuit for generating a gate drive signal for controlling the switching of the low side switch in dependence on the electrical feedback parameter, wherein the second control circuit has as its reference voltage supply the low voltage line and the second supply voltage greater than the voltage at the low voltage line. - a first input for receiving a voltage between the node and the resonant circuit; - a charge pump circuit for converting an AC voltage at the first input into a DC voltage and storing it on a first output capacitor (Co) as an output of the first generating circuit at the first supply voltage; and - a supply transistor between the high voltage line and the output of the first generating circuit for charging the output capacitor (Co) before the start-of-oscillation occurs; - a second generating circuit for generating a second supply voltage from the low voltage line and from the voltage at the node; - a first control circuit for generating a gate drive signal for controlling the switching of the high side switch in dependence on an electrical feedback parameter, wherein the first control circuit has as its reference voltage supply the voltage at the node and the first supply voltage greater than the voltage at the node; and - a second control circuit for generating a gate drive signal for controlling the switching of the low side switch in dependence on the electrical feedback parameter, wherein the second control circuit has as its reference voltage supply the low voltage line and the second supply voltage greater than the voltage at the low voltage line.