An AC-voltage-to-DC-voltage conversion circuit, comprising: four first bidirectional switches (S1, S2, S3, S4) forming a first H bridge, first and second input nodes of the bridge being respectively coupled to first and second nodes of application of the AC voltage; a transformer comprising a primary winding and a secondary winding, magnetically coupled, first and second ends of the primary winding being respectively coupled to first and second output nodes of the first bridge; a first inductance series-connected with the first bridge between the first input node of the bridge and the first node of application of the AC voltage; a second inductance series-connected with the first bridge, between the first output node of the bridge and the first end of the primary winding; and a control circuit capable of controlling the bridge alternately to a first configuration where the switches (S1, S3) of a first diagonal of the bridge are on and the switches of a second diagonal (S2, S4) of the bridge are off, and to a second configuration where the switches (S1, S3) of the first diagonal are off and the switches (S2, S4) of the second diagonal are on, the control circuit being capable, during a phase of transition between the first and second configurations, of successively: turning on a first switch of the second diagonal (S2, S4), while holding the first switch of the first diagonal (S1, S3) and the second switch of the first diagonal (S1, S3) in the on state and the second switch of the second diagonal (S2, S4) in the off state; turning off a first switch of the first diagonal (S1, S3) when the current flowing through this switch takes a zero value; turning on the second switch of the second diagonal (S2, S4), while holding the first switch of the second diagonal (S2, S4) and the second switch of the first diagonal (S1, S3) in the on state and the first switch of the first diagonal (S1, S3) in the off state; and turning off the second switch of the first diagonal (S1, S3) when the current flowing through this switch takes a zero value. four first bidirectional switches (S1, S2, S3, S4) forming a first H bridge, first and second input nodes of the bridge being respectively coupled to first and second nodes of application of the AC voltage; a transformer comprising a primary winding and a secondary winding, magnetically coupled, first and second ends of the primary winding being respectively coupled to first and second output nodes of the first bridge; a first inductance series-connected with the first bridge between the first input node of the bridge and the first node of application of the AC voltage; a second inductance series-connected with the first bridge, between the first output node of the bridge and the first end of the primary winding; and a control circuit capable of controlling the bridge alternately to a first configuration where the switches (S1, S3) of a first diagonal of the bridge are on and the switches of a second diagonal (S2, S4) of the bridge are off, and to a second configuration where the switches (S1, S3) of the first diagonal are off and the switches (S2, S4) of the second diagonal are on, the control circuit being capable, during a phase of transition between the first and second configurations, of successively: turning on a first switch of the second diagonal (S2, S4), while holding the first switch of the first diagonal (S1, S3) and the second switch of the first diagonal (S1, S3) in the on state and the second switch of the second diagonal (S2, S4) in the off state; turning off a first switch of the first diagonal (S1, S3) when the current flowing through this switch takes a zero value; turning on the second switch of the second diagonal (S2, S4), while holding the first switch of the second diagonal (S2, S4) and the second switch of the first diagonal (S1, S3) in the on state and the first switch of the first diagonal (S1, S3) in the off state; and turning off the second switch of the first diagonal (S1, S3) when the current flowing through this switch takes a zero value. turning on a first switch of the second diagonal (S2, S4), while holding the first switch of the first diagonal (S1, S3) and the second switch of the first diagonal (S1, S3) in the on state and the second switch of the second diagonal (S2, S4) in the off state; turning off a first switch of the first diagonal (S1, S3) when the current flowing through this switch takes a zero value; turning on the second switch of the second diagonal (S2, S4), while holding the first switch of the second diagonal (S2, S4) and the second switch of the first diagonal (S1, S3) in the on state and the first switch of the first diagonal (S1, S3) in the off state; and turning off the second switch of the first diagonal (S1, S3) when the current flowing through this switch takes a zero value.