A robust envelope following method applicable to both non-autonomous and oscillatory circuits

In this paper, we propose a novel envelope-following method which is uniformly applicable to both non-autonomous and oscillatory circuits. A key feature of our technique is the use of an efficient minimum least squares solution technique to solve an underdetermined envelope system directly. This leads to a general purpose approach which is much easier to solve than previous phase condition based envelope-following method, improving numerically robustness dramatically. We validate our method on a variety of autonomous and non-autonomous circuits, including a PLL in transition to lock. The new method provides speedups of 1-2 orders of magnitude over transient simulation, while obtaining results that are equally or more accurate.