Method for DC-DC boost insulated switching conversion including - operating the conversion through a transformer which includes a first winding and a second winding with a lower number of turns than the first winding and a central tap in the second winding separating it into first and second half-windings (13a, 13b) between the central tap and first and second outer terminals - applying a continuous input voltage to convert to a node and from there to said central tap of said second winding through an energy storage reactive circuit, in particular an inductor, - performing a switching by first and second main switches (M3, M4) to selectively connect said first or second outer terminals of said first or second half-windings (13a, 13b) to a fixed voltage reference - performing a limitation (P1, P2) of an in-rush current in said reactive circuit at power-on, said operation of limitation of an in-rush current (P1, P2) in said reactive circuit includes selectively connecting during said power-on phase each of said first or second outer terminals of said first or second half-windings (13a, 13b) to said node by means of respective first or second circuit branches (P1, P2), said branches each including at least a series diode (56, 57) that conducts current towards said node and an additional controlled transistor switch (M2, M1) under the control of an additional driving signal (Vc, Vd) driving, in the context of a power-on mode, said switches according to the following phases: - in a first phase (Fl) closing said first main switch and said first additional switch, keeping them closed until a current in the reactive storage circuit reaches a limit current value (Ip), which is in particular measured or estimated, keeping open said second main switch and said second additional switch (Ml); - in a second phase, opening said first main switch, keeping closed said first additional switch in order to let a current flow to the input node; - in a third phase closing said second main switch and said second additional switch, keeping them closed until the current in the reactive storage circuit reaches the limit current value (Ip) or for the time apt to reach said limit current value (Ip), keeping open said first main switch and said first additional switch; - in a fourth phase, opening said second main switch, keeping closed said second additional switch in order to let a current flow to the input node. characterized in that when, during a normal driving mode, a saturation condition of the transformer is detected, opening or holding open the first main switch and the second main switch and close or keep closed both additional switches (M2, M1), in order to let the reactive circuit discharge through both circuit branches (P1, P2) till reaching a current safety value. - operating the conversion through a transformer which includes a first winding and a second winding with a lower number of turns than the first winding and a central tap in the second winding separating it into first and second half-windings (13a, 13b) between the central tap and first and second outer terminals - applying a continuous input voltage to convert to a node and from there to said central tap of said second winding through an energy storage reactive circuit, in particular an inductor, - performing a switching by first and second main switches (M3, M4) to selectively connect said first or second outer terminals of said first or second half-windings (13a, 13b) to a fixed voltage reference - performing a limitation (P1, P2) of an in-rush current in said reactive circuit at power-on, - in a first phase (Fl) closing said first main switch and said first additional switch, keeping them closed until a current in the reactive storage circuit reaches a limit current value (Ip), which is in particular measured or estimated, keeping open said second main switch and said second additional switch (Ml); - in a second phase, opening said first main switch, keeping closed said first additional switch in order to let a current flow to the input node; - in a third phase closing said second main switch and said second additional switch, keeping them closed until the current in the reactive storage circuit reaches the limit current value (Ip) or for the time apt to reach said limit current value (Ip), keeping open said first main switch and said first additional switch; - in a fourth phase, opening said second main switch, keeping closed said second additional switch in order to let a current flow to the input node.