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One advance in technology could have a big impact on PDN design: the incorporation
of nonlinear solutions in DC-to-DC converters. By using simple, nonlinear features
or more advanced nonlinear functions such as model predictive control, it may be
possible to design PDNs that use fewer components while more effectively regulating
transient voltage fluctuations. One challenge for PDN designers is that when using
nonlinear features, you can no longer use the target impedance or other frequency
domain methodologies for your design because these approaches assume a linear
time invariant behavior.
The industry is working on incorporating nonlinear features into their models for
simulations, but achieving a high enough degree of fidelity between the models and the
physical circuits is still a work in progress. With less confidence in the models using
nonlinear solutions, we tend to overdesign the PDN to give ourselves some elbow room
in case the nonlinear behaviors are not as good as we would need them to be, and then
optimize the solution for cost in the lab. That sacrifices some of the density advantage
we might gain from nonlinear components. As nonlinear modeling improves, we hope to
be able to design smaller PDNs with fewer components.
'' As nonlinear
modeling
improves, we
hope to be able
to design smaller
PDNs with fewer
components."