ML-PTA: A Two-Stage ML-Enhanced Framework for Accelerating Nonlinear DC Circuit Simulation With Pseudo-Transient Analysis

Direct current (DC) analysis lies at the heart of integrated circuit design in seeking DC operating points. Although pseudo-transient analysis (PTA) methods have been widely used in DC analysis in both industry and academia, their initial parameters and stepping strategy require expert knowledge and labor tuning to deliver efficient performance, which hinders their further applications. In this paper, we leverage the latest advancements in machine learning to deploy PTA with more efficient setups for different problems. More specifically, active learning, which automatically draws knowledge from other circuits, is used to provide suitable initial parameters for PTA solver, and then calibrate on-the-fly to further accelerate the simulation process using TD3-based reinforcement learning (RL). To expedite model convergence, we introduce dual agents and a public sampling buffer in our RL method to enhance sample utilization. To further improve the learning efficiency of the RL agent, we incorporate imitation learning to improve reward function and introduce supervised learning to provide a better dual-agent rotation strategy. We make the proposed algorithm a general out-of-the-box SPICE-like solver and assess it on a variety of circuits, demonstrating up to 3.10$\boldsymbol\times$ reduction in NR iterations for the initial stage and 285.71$\boldsymbol\times$ for the RL stage.