A buck converter having an input (in) and an output (out) and comprising: a high-side switch, a low-side switch, a protection switch (7,7') and a shutter switch, each of said switches having a respective control terminal and respective first and second main terminals; the first main terminal of the low-side switch being connected to a ground, the first main terminal of the high side switch and the second main terminal of the low side switch being connected to a converter node, the second main terminal of the high-side switch being connected to the second main terminal of the protection switch (7,7') and the first main terminal of the protection switch being connected to an input node (in) such that the high-side switch and the protection switch (7, 7') are in anti-series, the first main terminal of the shutter switch being connected, directly or indirectly, to the control terminal of the protection switch (7,7') the control terminal of the shutter switch being electrically coupled, directly or indirectly, to the input node (in), and the second main terminal of the shutter switch being directly connected to the output (out), wherein either (a) the buck converter further comprises a bootstrap supply arrangement arranged for supplying the control terminal of the protection switch, and the protection switch is a NMOS transistor and the control terminal of the shutter switch is electrically directly coupled to the input node (in); or (b) the protection switch is a PMOS transistor and the control terminal of the shutter switch is electrically coupled to the input node (in) by a floating supply (V float) for providing an offset voltage from a voltage at the input node (in). a high-side switch, a low-side switch, a protection switch (7,7') and a shutter switch, each of said switches having a respective control terminal and respective first and second main terminals; the first main terminal of the low-side switch being connected to a ground, the first main terminal of the high side switch and the second main terminal of the low side switch being connected to a converter node, the second main terminal of the high-side switch being connected to the second main terminal of the protection switch (7,7') and the first main terminal of the protection switch being connected to an input node (in) such that the high-side switch and the protection switch (7, 7') are in anti-series, the first main terminal of the shutter switch being connected, directly or indirectly, to the control terminal of the protection switch (7,7') the control terminal of the shutter switch being electrically coupled, directly or indirectly, to the input node (in), and the second main terminal of the shutter switch being directly connected to the output (out), wherein either (a) the buck converter further comprises a bootstrap supply arrangement arranged for supplying the control terminal of the protection switch, and the protection switch is a NMOS transistor and the control terminal of the shutter switch is electrically directly coupled to the input node (in); or (b) the protection switch is a PMOS transistor and the control terminal of the shutter switch is electrically coupled to the input node (in) by a floating supply (V float) for providing an offset voltage from a voltage at the input node (in). (a) the buck converter further comprises a bootstrap supply arrangement arranged for supplying the control terminal of the protection switch, and the protection switch is a NMOS transistor and the control terminal of the shutter switch is electrically directly coupled to the input node (in); or (b) the protection switch is a PMOS transistor and the control terminal of the shutter switch is electrically coupled to the input node (in) by a floating supply (V float) for providing an offset voltage from a voltage at the input node (in).