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

A method of controlling a DC-DC step-up converter including at least one power switch and an energy storage inductor, comprising:

• comparing a signal representing a converter output voltage to a first threshold;
• generating a first comparison flag based on the converter output voltage comparison;
• comparing a signal representing a voltage across the energy storage inductor to a second threshold;
• generating a second comparison flag based on the energy storage inductor voltage comparison;
• controlling the at least one power switch based upon the first comparison flag and the second comparison flag;
• and
• stepwise adjusting the second threshold based upon the first comparison flag and the second comparison flag to limit a ripple on the converter output voltage.

A DC-DC step-up converter comprising:

• a first comparator to compare a signal representing a converter output voltage with a first threshold, and to generate a first comparison flag based on the converter output voltage signal comparison;
• a second comparator to compare a signal representing voltage across an energy storage inductor with a second threshold, and to generate a second comparison flag based on the energy storage inductor signal comparison;
• a power switch control circuit having inputs to receive the first comparison flag and second comparison flag and to control at least one power switch;
• and
• a circuit to establish the second threshold, the circuit having inputs to receive the first comparison flag and second comparison flag and to adjust the second threshold as a function of the first and second comparison flags.

A DC-DC step-up converter comprising:

• at least one power switch;
• an energy storage inductor;
• a first comparator to compare a signal representing a converter output voltage with a first threshold, and to generate a first comparison flag based on the converter output voltage signal comparison;
• a second comparator to compare a signal representing a voltage across said energy storage inductor with a second threshold, and to generate a second comparison flag based on the energy storage inductor signal comparison;
• a power switch control circuit having inputs to receive the first comparison flag and second comparison flag and to control said at least one power switch;
• and
• a circuit to establish the second threshold, the circuit having inputs to receive the first comparison flag and second comparison flag and to adjust the second threshold as a function of the first and second comparison flags.