AN EFFICIENT NONQUASI-STATIC DIODE MODEL FOR CIRCUIT SIMULATION

Based on the partitioned-charge-based modeling approach, a general nonquasi-static dynamic charge element is derived to simulate both transient behavior and high-frequency characteristics of semiconductor diode. A new model parameter tau is introduced to describe the dynamic charge redistribution time for a diode. By partitioning the total base charge into quasi-static (QS) and nonquasi-static (NQS) terms, a single-tau (level 2) diode model is first derived. By further dividing the NQS charge, a double-tau (level 3) diode model is proposed to describe different reverse recovery processes. In addition, a voltage-dependent equation is incorporated to the double-tau model into account for the dynamic charge partitioning. We show that the SPICE diode (level-1) model is included by setting tau to zero as a special case of the proposed models. The new diode model has been implemented in MISIM, a model independent SPICE-like simulation framework. Significant improvement in accuracy over the traditional SPICE diode model in both time and frequency domain has been demonstrated, while achieving the same or even better simulation speed and reliability.