Abstract: A current monitoring circuit for use with an inductor having a magnetizing phase and a de-magnetizing phase is presented. The current monitoring circuit has a voltage controlled oscillator and a first counter. The voltage controlled oscillator generates a clock signal based on a voltage across the inductor. The first counter generates a counter value using the clock signal. The current monitoring circuit may be implemented as part of a switched mode power supply having an inductor coupled to a pair of power switches and a controller adapted to generate a control signal to control the pair of power switches based on the counter value.