Enhancing Reliability of Analog Neural Network Processors

Recently, analog and mixed-signal neural network processors have been extensively studied due to their better energy efficiency and small footprint. However, analog computing is more vulnerable to circuit nonidealities such as process variation than their digital counterparts. On-chip calibration circuits can be adopted to measure and compensate for those effects, but it leads to unavoidable area and power overheads. In this brief, we propose a variation and noise-tolerant learning algorithm and postsilicon process variation compensation technique which does not require any additional monitoring circuitry. The proposed techniques reduce the accuracy degradation in the corrupted fully connected network down to 1% under large amount of variations including 10% unit capacitor mismatch, 8-mV rms comparator noise and 20-mV rms comparator offset.