A SUBTHRESHOLD ANALOG MOS CIRCUIT FOR LOTKA–VOLTERRA CHAOTIC OSCILLATOR

We fabricated an analog integrated circuit (IC) that implements the Lotka–Volterra (LV) chaotic oscillator presented by Mimura and Kan-on [1986]. The LV system describes periodic or chaotic behaviors in prey–predator systems in simple mathematical form, and is suitable for analog IC implementation [Asai et al., 2003]. The proposed circuit consists of a small number of metal-oxide-semiconductor field-effect transistors (MOS FETs) operating in their subthreshold region. A new scaling factor of system variables, which was not discussed in [Asai et al., 2003], is also introduced for quantitative studies of designing practical hardware LV systems.