Toward Wave Digital Filter based Analog Circuit Emulation on FPGA (Abstract Only)

Software simulation of analog and mixed-signal circuits often takes a long computing time. Unlike digital circuits that can be validated by FPGA emulation, there is no winning emulation solution for analog circuits. As the first step to applying wave digital filter (WDF) to emulate post-layout analog circuits, we present how to map linear and nonlinear components in an original circuit to WDFs with exactly same behaviors. To validate, we implement the emulation circuit (i.e., WDFs) in FPGA. To be more specific, each emulation time step is executed as a finite state machine, while all the computing resource, e.g. floating point units (FPU), are shared as a resource pool and used only when it is necessary, which result in a very small resource consumption on FPGA. Virtually perfect match is obtained between the Verilog and SPICE simulations for a number of primitive analog circuits, indicating the high accuracy of the proposed emulation. In terms of runtime, the WDF implementation is about 3-4x faster than HSPICE on a small two-stage differential amplifier circuit. And better speedup can be anticipated when it scales to larger circuits because of the underlying binary tree structure of the WDF implementation.