An Efficient Method to Simulate Threshold-Crossing Events

In this work, a new and efficient method is developed to simulate threshold-crossing events (for example, the cross event in Verilog-A/MS). The method converges directly to the solution at the crossing without the need of computing additional timepoints. The violated cross condition is solved together with the circuit equations as one system of nonlinear equations and the timestep is treated as an independent variable. This method has very little overhead and can be easily integrated into an existing simulation flow. Simulation results show good convergence rate-less than two extra Newton iterations needed to accurately locate the crossing. This method could speedup transient simulation significantly when there are a large number of threshold-crossing events.