Transient simulation of integrated circuits in the charge-voltage plane

Transient simulation has traditionally been performed in the current-voltage plane (with current and voltage as variables) for verification of integrated circuits and systems. This paper introduces techniques for efficient and accurate transient simulation in the charge-voltage plane (with charge and voltage as variables). For integrated circuits, both simulation cost and overhead to increase accuracy are drastically reduced by performing simulations in the charge-voltage plane. Adaptively controlled explicit simulation in charge-voltage plane is used to demonstrate the feasibility of the approach. Solution of circuit equations in the charge-voltage plane is 10-20 times more efficient than in the current-voltage plane. Furthermore, simulation accuracy can be increased at an incremental cost. As a result, ACES in the charge-voltage plane provides speedups of 300×-5000× or more over traditional circuit simulators with little or no loss in circuit timing accuracy, and simulates circuits containing more than million transistors