Circuit Optimization Using the Simplex Algorithm

A large fraction of the circuit design engineer’s time is spent in optimiza-tion of circuit parameters. An optimization program for SPICE circuit design using the Simplex algorithm is described. This technique can relieve the engi-neer from much of the tedium involved in circuit optimization. Any number of parameters, such as resistor values, currents and transistor sizes, may be automat-ically adjusted to optimize an objective measure of circuit performance. To date, a wide variety of circuits have been optimized, including: several MODFET digital cells, an HP3X high-speed output stage, HP3X and HBT com-parators and an HBT sample and hold. Ke y performance measures have been improved up to 1.5x over hand designs by a skilled engineer. This paper describes the Simplex algorithm and demonstrates it’s applica-tion to circuit design. Some pitfalls and heuristics for designing viable objective functions are discussed