Transient sensitivity computation in controlled explicit piecewise linear simulation

This paper presents a general method for computing transient sensitivities using both direct and adjoint methods in controlled explicit event driven simulation algorithms that employ piecewise linear device models. Sensitivity information provides first order assessment of circuit variability with respect to design variables and parasitics, This information is particularly useful for noise analysis, timing rule generation, and circuit optimization. Techniques for incorporating transient sensitivity into adaptively controlled explicit simulation, a general piecewise linear simulator, are presented. Sensitivity computation includes algorithms to handle instantaneous charge redistribution due to the discontinuous conductance models of the piecewise linear elements, and the loss of simulation accuracy due to the nonmonotonic responses in autonomous adjoint circuits with nonzero initial conditions. Results demonstrate the efficiency and accuracy of the proposed techniques.