A method of operating a converter, wherein the converter comprises: a transformer having a first winding and a second winding; a first full-bridge coupled to the first winding of the transformer and comprising a first leg and a second leg; and a rectifier circuit coupled to the second winding of the transformer; an auxiliary circuit comprising an auxiliary inductor, an auxiliary capacitor, an auxiliary transistor and a diode or a synchronous rectifier, wherein the auxiliary inductor is coupled to the rectifier circuit, the auxiliary transistor is coupled between a first node of the auxiliary capacitor and the auxiliary inductor, and the diode or the synchronous rectifier is coupled between a second node different from the first node of the auxiliary capacitor and the auxiliary inductor, the method comprising: injecting an auxiliary current (I aux) into the rectifier circuit via the auxiliary inductor, wherein the injected auxiliary current (I aux) causes a voltage across a first transistor of the first leg of the first full-bridge to decrease; wherein the step of injecting an auxiliary current (I aux) is performed by the following steps: turning on the auxiliary transistor before or during a dead time of the first leg of the full-bridge coupled to the first winding of the transformer to inject the auxiliary current; turning off the auxiliary transistor during the dead time of the first leg of the full-bridge coupled to the first winding of the transformer; turning on the first transistor of the first full-bridge after a safety phase during which the auxiliary transistor is turned off and the first transistor and a second transistor of the first leg of the first full-bridge are turned off. wherein the converter comprises: a transformer having a first winding and a second winding; a first full-bridge coupled to the first winding of the transformer and comprising a first leg and a second leg; and a rectifier circuit coupled to the second winding of the transformer; an auxiliary circuit comprising an auxiliary inductor, an auxiliary capacitor, an auxiliary transistor and a diode or a synchronous rectifier, wherein the auxiliary inductor is coupled to the rectifier circuit, the auxiliary transistor is coupled between a first node of the auxiliary capacitor and the auxiliary inductor, and the diode or the synchronous rectifier is coupled between a second node different from the first node of the auxiliary capacitor and the auxiliary inductor, a transformer having a first winding and a second winding; a first full-bridge coupled to the first winding of the transformer and comprising a first leg and a second leg; and a rectifier circuit coupled to the second winding of the transformer; an auxiliary circuit comprising an auxiliary inductor, an auxiliary capacitor, an auxiliary transistor and a diode or a synchronous rectifier, wherein the auxiliary inductor is coupled to the rectifier circuit, the auxiliary transistor is coupled between a first node of the auxiliary capacitor and the auxiliary inductor, and the diode or the synchronous rectifier is coupled between a second node different from the first node of the auxiliary capacitor and the auxiliary inductor, the method comprising: injecting an auxiliary current (I aux) into the rectifier circuit via the auxiliary inductor, wherein the injected auxiliary current (I aux) causes a voltage across a first transistor of the first leg of the first full-bridge to decrease; wherein the step of injecting an auxiliary current (I aux) is performed by the following steps: turning on the auxiliary transistor before or during a dead time of the first leg of the full-bridge coupled to the first winding of the transformer to inject the auxiliary current; turning off the auxiliary transistor during the dead time of the first leg of the full-bridge coupled to the first winding of the transformer; turning on the first transistor of the first full-bridge after a safety phase during which the auxiliary transistor is turned off and the first transistor and a second transistor of the first leg of the first full-bridge are turned off. turning on the auxiliary transistor before or during a dead time of the first leg of the full-bridge coupled to the first winding of the transformer to inject the auxiliary current; turning off the auxiliary transistor during the dead time of the first leg of the full-bridge coupled to the first winding of the transformer; turning on the first transistor of the first full-bridge after a safety phase during which the auxiliary transistor is turned off and the first transistor and a second transistor of the first leg of the first full-bridge are turned off.