Continuous-time feedback in floating-gate MOS circuits

We present the negative- and positive-feedback circuit configurations of continuous-time floating-gate MOS circuits. We start by reviewing the dynamics of our pFET and nFET single-transistor synapses. We present the range of possible stabilizing and destabilizing types of feedback in circuits with one floating-gate synapse, including data from nFET and pFET synapses. We then show examples of competitive and cooperative behavior in multiple-synapse circuits. We present experimental data from circuits fabricated in the 2-/spl mu/m n-well CMOS process available through MOSIS. We see similar experimental effects in 1.2and 0.5-/spl mu/m processes.