Method of controlling a DC-DC convertor in discontinuous mode

A method of controlling a DC-DC converter, wherein the DC-DC converter includes an induction coil as a reactive element for supplying, in cooperation with a set of at least two alternately operating switches, an output voltage with a higher, equal or lower level than a level of an input voltage provided by a continuous voltage source, wherein the induction coil has terminals, and wherein the method includes the following steps:

• (a) in each successive control cycle, performing a first phase wherein a first control signal controls at least a first switch to make the first switch conductive and to increase a current through the induction coil during a first determined duration;
• and
• (b) after the first phase, performing a second phase, wherein a second control signal controls at least a second switch to make the second switch conductive and to decrease current through the induction coil during a second adjustable duration, wherein detection means is disposed to detect, at the end of the second phase, a sign of any overvoltage across one of the terminals of the induction coil, connected to the at least two alternating operating switches and for supplying a detection signal, wherein the detection signal is maintained for a determined duration, prior to detection of another successive cycle, in a high state or a low state depending upon sign of detected overvoltage, and timing means that receive the detection signal operate to adapt, in each successive cycle, the second duration of the second phase so as to cancel out current in the induction coil at the end of the second phase.