frequency to retain the triangular shape of the inductor current. It will be assumed in the following, therefore, that.the output signal of amplifier A, includes a remnant of the inductor current triangular waveform (except for possible curvature of the corners) multiplied by a constant (kJ. In CM realisation (Fig. 2), the output of the error amplifier V;, modified by a 'compensation slope' Mc [1] is compared to the inductor current IL having a rising slope k,ml' a falling slope k,m2 and low frequency component A. The average SIM D' generator SIM