DVS for on-chip bus designs based on timing error correction

On-chip buses are typically designed to meet performance constraints for worst-case conditions, including process corner, temperature, IR-drop, and neighboring net switching pattern. This can result in significant performance slack at more typical operating conditions. We propose a dynamic voltage scaling (DVS) technique for buses, based on a double sampling latch which can detect and correct for delay errors without the need for retransmission. The proposed approach recovers the available slack at non-worst-case operating points through more aggressive voltage scaling and track changing conditions by monitoring the error recovery rate. Voltage margins needed in traditional designs to accommodate worst-case performance conditions are therefore eliminated, resulting in a significant improvement in energy efficiency. The approach was implemented for a 6 mm memory read bus operating at 1.5 GHz (0.13 μm technology node) and was simulated for a number of benchmark programs. Even at the worst-case process and environment conditions, energy gains of up to 17% are achieved, with error recovery rates under 2.3%. At more typical process and environment conditions, energy gains range from 35% to 45%, with a performance degradation under 2%. An analysis of optimum interconnect architectures for maximizing energy gains with this approach shows that the proposed approach performs well with technology scaling.