A control device for a switching power supply.

A control device controls a switching converter. The converter has an input alternating supply voltage, a regulated direct voltage on the output terminal, and a switch connected to an inductor. The control device controls the closing and opening time period of said switch for each cycle and receives a first input signal representative of the current flowing through one element of the converter. The control device comprises a counter configured to count a time period, a comparator configured to compare said first input signal with a second signal, digital control block configured to control the closing and opening of said switch and to activate said counter to start the counting of said time period when the said first input signal crosses said second signal, with said switch being closed. The digital control block is configured to open the switch when the counter finishes the counting of said time period.