Behavioral Modeling of Transistor-Level Circuits using Automatic Abstraction to Hybrid Automata
Ahmad Tarrafa and Lars Hedrichb
Goethe University Frankfurt, Germany
atarraf@em.cs.uni-frankfurt.de
bhedrich@em.cs.uni-frankfurt.de
ABSTRACT
Accurate abstracted behavioral modeling of analog circuits is still an open problem, especially when the abstraction process is automated. In this paper we present an automated abstraction technique of transistor level circuits with full SPICE accuracy alongside a significant simulation speed-up. The methodology computes a hybrid automaton which is transformed into a behavioral model in Verilog-A. The resulting hybrid automaton exhibits linear behavior as well as the technology dependent nonlinear e.g. limiting behavior. The accuracy and speed-up of the methodology is evaluated on several transistor level circuits ranging from simple operational amplifiers up to a complex industrial OTA-based Gm/C filter. Finally, we formally verify the equivalence between the generated model and the original circuit.
Keywords: Abstraction, Verification, Hybrid automaton, Verilog-A, Behavioral modeling.
