## Optimizing Dominant Time Constant in RC CircuitsL. Vandenberghe, S. Boyd, and A. El Gamal
Full report: rc.pdf Final paper: rc_final.pdf Matlab code for the examples. To run these Matlab scripts, you need CVX.
We propose to use the dominant time constant of a resistor-capacitor (RC)
circuit as a measure of the signal propagation delay through the circuit. We
show that the dominant time constant is a quasiconvex function of the
conductances and capacitances, and use this property to cast several
interesting design problems as convex optimization problems, specifically,
semidefinite programs (SDPs). For example, assuming that the conductances and
capacitances are affine functions of the design parameters (which is a common
model in transistor or interconnect wire sizing), one can minimize the power
consumption or the area subject to an upper bound on the dominant time
constant, or compute the optimal tradeoff surface between power, dominant time
constant, and area. We will also note that, to a certain extent, convex
optimization can be used to design the topology of the interconnect wires. This
approach has two advantages over methods based on Elmore delay optimization.
First, it handles a far wider class of circuits, |