A Jitter Amplification Phenomenon in Multisampled Digital Control of Power Converters

This paper investigates a nonlinear phenomenon related to multisampling control of power converters. The nonlinearity, manifested as increased gain regions in static modulator transcharacteristic, is caused by the discontinuity of the modulating waveform, and can result in increased jittering of the duty-cycle. The paper proposes a statistical model for predicting the jittering impact on the duty cycle variance, analytic derivations for the jittering conditions, and an anti-jittering algorithm. A numerically obtained static modulator transcharacteristic is given to illustrate the increased gain regions. Verifications, performed on a multisampled digitally controlled buck converter, show a good match between the theoretical analysis, simulations and experimental results. This paper is accompanied by videos demonstrating the jitter amplification and the algorithm operation.