A controller includes a comparator having an inverting input coupled to a voltage converter output, a non-inverting input coupled to a voltage source, and an output. The controller includes a timer having a start input coupled to the converter that indicates that current through a converter inductor is less than a threshold; a stop input coupled to the comparator output; and an output having a digital value corresponding to the time between receiving asserted signals at start input and at stop input. The controller includes a time comparator having a first input coupled to the timer output and a second input to receive a time value. The time comparator asserts one of its outputs based on the digital and time values. The controller includes an accumulator coupled to the time comparator outputs, the accumulator configured to maintain, increase, or decrease an output value based on the asserted time comparator output.