2015 Volume 6 Issue 4 Pages 570-581
In order to develop large-scale nonlinear dynamical systems using CMOS integrated circuits, we propose a core circuit for coupled map lattice (CML) models. The characteristics of the core circuits in the lattice on a chip are not generally equal, which is caused by CMOS device mismatches, including parasitic capacitance and wiring resistance. The proposed circuit solves this problem; it compensates for a DC offset voltage variation by holding it at a capacitor, and also for current variation by adjusting the bias voltage of a current source automatically so as to bring the current close to a target value. The proposed core circuit has been designed and fabricated using TSMC 0.25 µm CMOS technology. The measurement results using the fabricated circuit have shown that the bit precision is more than 8 bits, even if there is a DC offset voltage of 100 mV or a bias-voltage change of 100 mV in a switched current source.