For feedback Handle we Commonly use a self changing PWM circuit, which widens the heartbeat width all through reduced battery or high load, and narrows it proportionately all through no load or optimum battery ailments. For your reference, efficient permeability of typical transformer core ferrites Employed in SMPS would http://glider-rocker-chair65319.bluxeblog.com/22665080/the-greatest-guide-to-ferrite-bead-symbol