Switched-Inductor Power Supplies: Compact Control Loops

Switched-inductor power supplies are pervasive in electronics. This is because they deliver a large fraction of the power they draw from the input source with an output voltage or current that is largely independent of the load. Keeping the output voltage or current steady this way is ultimately the responsibility of the feedback controller. This talk uses insight and intuition to show how pulse-width-modulated (PWM) and hysteretic loops switch the inductor, offset the current or voltage they control, and respond to load dumps. The presentation also shows how summing comparators work and how they can contract, offset, and compensate (for reduced offset) these control loops. With this background and understanding in hand, designing compact feedback controllers for switched-inductor power supplies is more straightforward.