This paper proposes an autotuning technique for digitally controlled voltage-mode dc-dc converters based on the model reference approach. The proposed solution uses the difference between the measured system impulse response and the reference one, determined by the desired dynamic performances, and minimizes the error function acting on the regulator parameters. Two different approaches have been investigated for the evaluation of the impulse response: a deterministic one, based on duty cycle impulse, and a statistical one, based on white noise injection. Compared to existing approaches, this solution has the advantage of simplicity, small-signal processing and on-line tuning capabilities. Experimental investigation has been performed on a 20 A, 1.5V synchronous buck converter, and both simulation and experimental results confirm the effectiveness of the proposed solution.
