Designer-like Automated Circuit Sizing for Multiloop LDO

Manual circuit sizing is an iterative process that negatively impacts the productivity and work satisfaction of experienced analog circuit designers. Thus, many automated circuit sizing methods have been proposed recently. However, they have poor performances on highly unstable circuits for which most of the simulations fail to converge. We propose a simple, yet powerful technique that can be used in conjunction with the state-of-the-art optimization algorithms for circuit sizing. This technique is inspired by the analog designers’ way of working. First, the algorithm finds the stability region by optimizing for the nominal corner, then it takes the other operating corners into consideration for the rest of the optimization process. We test our sizing method on a multiloop LDO for which the classical automated sizing methods cannot find circuit configurations that meet the specifications.