Limit-cycle oscillation (LCO) generation by altering a digital transfer function of a feedback loop element

A switching power converter circuit, comprising:

• a magnetic storage element;
• a switching circuit coupled to the magnetic storage element for energizing the magnetic storage element;
• a capacitive storage element coupled to the magnetic storage element, wherein the capacitive storage element is charged by a current transferred from the magnetic storage element to provide an output terminal adapted for coupling to a load;
• a sensing circuit for sensing at least one of a current or a voltage provided at the output terminal;
• a control circuit having an input coupled to an output of the sensing circuit and an output coupled to the switching circuit, for controlling the switching circuit according to a feedback path from an output of the sensing circuit to an input of a modulator that controls the switching circuit, wherein the feedback path includes at least one digital element, and wherein the control circuit is responsive to a control signal to alter a transfer function of the at least one digital element within the feedback path to cause generation of a limit-cycle oscillation within the feedback path;
• and
• a limit-cycle oscillation measurement circuit for measuring characteristics of the limit-cycle oscillation, whereby characteristics of the switching power converter are obtained.