Method of controlling a step-up DC-DC converter and related converter

摘要

The value of the maximum current through an energy storage inductor of a DC-DC step-up converter is increased stepwise up to attain a maximum pre-established value. A relatively low current threshold is thus set in presence of a load that absorbs a relatively small current and a higher current threshold when the load absorbs a relatively large current. The output voltage of the converter and the inductor voltage are compared with respective thresholds, thus depending from the result of these distinct comparisons, the ripple of the output voltage of the converter is effectively limited by adjusting the comparison threshold of the inductor voltage. The number of occurrences of the output voltage of the converter reaching its respective threshold is down counted and the number of occurrences of the inductor voltage reaching its respective threshold is up-counted: when the resulting count attains a certain value, the comparison threshold of the inductor voltage is incremented and the counting is reset.