A Power Efficient System Design Methodology Employing Approximate Arithmetic Units

In this work a power efficient approximate system design methodology is introduced and its performance is demonstrated by a 2D-DCT implementation on Spartan 3 FPGA. The method is applicable to any system with arithmetic computation regardless of their architecture, because it utilizes the existing approximate arithmetic units. The novelty of the proposed method is its system analysis approach starting from the highest level and exploring through the sub-blocks down to the basic arithmetic units. It first evaluates a given system block diagram and sets the desired performance limits of each processing block to achieve the desired ultimate quality metric. Then, the arithmetic power consumption is minimized by employing the appropriate arithmetic units which are chosen by linear/non-linear programming with linear constraint solver. The tests on 2D-DCT implementation show a power reduction of 8% for a 0.01 dB PSNR loss for 128x128 images, on the average.