A Fast Pruning Technique for Low-Power Inexact Circuit Design

Inexact Circuits are circuits in which the accuracy of the output can be traded for cost savings (energy, area and/or delay). In the context of advanced technology scaling and power density increase, inexact circuits appear to be very promising as a solution. In this paper, we present a novel pruning technique developed as a logic level method to select and prune parts of a digital circuit. The error is computed at each pruning step using probabilistic error propagation and Hamming distance computation, making the evaluation possible at runtime. The technique was validated on several parallel adder architectures. Experimental results proved the efficiency of the technique with Energy-Delay-Area product reduction of 1.8× for less than 10−4% of relative error on the considered benchmarks at 45-nm technology node.