Total power reduction in CMOS circuits via gate sizing and multiple threshold voltages

Minimizing power consumption is one of the most important objectives in IC design. Resizing gates and assigning different V/sub t/'s are common ways to meet power and timing budgets. We propose an automatic implementation of both these techniques using a mixed-integer linear programming model called MLP-exact, which minimizes a circuit's total active-mode power consumption. Unlike previous linear programming methods which only consider local optimality, MLP-exact can find a true global optimum. An efficient, non-optimal way to solve the MLP model, called MLP-fast, is also described. We present a set of benchmark experiments which show that MLP-fast is much faster than MLP-exact, while obtaining designs with only slightly higher power consumption. Furthermore, the designs generated by MLP-fast consume 30% less power than those obtained by conventional, sensitivity-based methods.