Design of Low-Power Approximate Logarithmic Multipliers with Improved Accuracy

Arab Nezhad, Mojtaba; Mahani, Ali

doi:10.22055/jaree.2021.36119.1018

Document Type : Research article

Authors

Department of Electrical Engineering, Shahid Bahonar University of Kerman, Kerman 7616913439, Iran

https://doi.org/10.22055/jaree.2021.36119.1018

Abstract

Approximate computing is considered a promising way to design high-performance and low-power arithmetic units recently. This paper proposes an energy-efficient logarithmic multiplier for error-tolerant applications. The proposed multiplier uses a novel technique to calculate the powers of two products to reduce critical path complexity. Also, a correction term is provided to improve the multiplier accuracy. Additionally, the use of approximate adders in our design is investigated, and optimal truncation length is obtained through simulations. We evaluated our work both in accuracy and hardware criteria. Experiments on a 16-bit proposed multiplier with approximate adder show that power-delay product (PDP) is significantly reduced by 34.05% compared to the best logarithmic multipliers available in the literature, while the mean relative error distance (MRED) is also decreased by 21.1%. The results of embedding our multiplier in the dequantization step of the JPEG standard show that the image quality is improved in comparison with other logarithmic multipliers. In addition, a subtle drop in image quality compared to utilizing exact multipliers proves the viability of our design.

Highlights

• A new multiplication algorithm that uses less hardware resources than previous designs and is, therefore, more power-efficient.
• A correction term that improves the multiplier error characteristic.
• A new method to calculate the product of the power of number two, which reduces the critical path delay significantly.
• Using approximate adders in the proposed design has been investigated.

Keywords

Main Subjects

Electronics

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