Adaptive performance compensation with in-situ timing error prediction for subthreshold circuits

This paper presents an adaptive technique for compensating manufacturing and environmental variability in subthreshold circuits using ldquocanary Flip-Floprdquo that can predict timing errors. A 32-bit Kogge-Stone adder whose performance was controlled by body-biasing was fabricated in a 65 nm CMOS process. Measurement results show that the adaptive control can compensate PVT variations and improve energy-efficiency of subthreshold circuits significantly compared to worst-case design and operation with guardbanding.