source terminal of the transistor mh1 and a drain terminal of the transistor mh2 are connected to the first terminal of a load l1 from which an output signal vout1 is obtained the second terminal of the load l1 being connected to the earth terminal the transistors mh1 and mh2 are controlled by means of a device 205 produced in integrated form in a chip of semiconductor material comprising a block 210 which is connected to a gate terminal of the transistors mh1 and mh2 and which generates two switching control signals sh1 and sh2 for the transistors mh1 and mh2 respectively a block 250 which receives as inputs one or more filtered reference quantities qref 39 and the control signal sh2 generates a dead time signal sd this signal is used by the control block 210 to keep both of the transistors mh1 and mh2 cut off for a predetermined period td dead time so as to prevent current peaks in these transistors during the switching stages the dead time block 250 also generates a filtering signal sf1 which is used as in the previous embodiment by the switch 122 and by the service block 140 this embodiment of the present invention is particularly advantageous since it enables the filtering signal sf1 to be produced by a simple modification of a pre existing circuit block without the need for a suitable filtering block 135 in fig1 a in order to explain the operation of the system of fig2 a reference.