Circuit Simulation Variability Modeling

The patent segments the continuous distribution of device performance into discrete histograms with multiple bins representing different performance levels (e.g., fast, typical, slow). Each histogram is divided into sub-ranges with defined probabilities, allowing the simulator to model manufacturing variability without requiring exhaustive simulation of every possible device combination. This segmentation enables accurate prediction of circuit behavior under variability while maintaining computational feasibility.

The patent applies partial action by selectively modeling variability at the histogram level rather than simulating every individual device variation. The simulator uses probabilistic histograms to represent device performance distributions and samples from these histograms during simulation, capturing the essential effects of manufacturing variability without the computational burden of exhaustive individual device modeling. This approach provides sufficient accuracy for reliability assessment while maintaining simulation efficiency.

The patent applies local quality by allowing different histogram configurations and binning strategies for different circuit components based on their specific variability characteristics. Each component can have its own tailored histogram model with appropriate number of bins and probability distributions, rather than forcing a uniform complex model across all components. This enables accurate variability capture for each component while keeping individual models manageable and computationally tractable.