Enhanced Hybrid Temporal Computing Using Deterministic Summations for Ultra-Low-Power Accelerators

Fuente: arXiv
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Autori principali: Sachdeva, Sachin, Lu, Jincong, Li, Wantong, Tan, Sheldon X. -D.
Natura: Preprint
Pubblicazione: 2025
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author Sachdeva, Sachin
Lu, Jincong
Li, Wantong
Tan, Sheldon X. -D.
author_facet Sachdeva, Sachin
Lu, Jincong
Li, Wantong
Tan, Sheldon X. -D.
contents This paper presents an accuracy-enhanced Hybrid Temporal Computing (E-HTC) framework for ultra-low-power hardware accelerators with deterministic additions. Inspired by the recently proposed HTC architecture, which leverages pulse-rate and temporal data encoding to reduce switching activity and energy consumption but loses accuracy due to its multiplexer (MUX)-based scaled addition, we propose two bitstream addition schemes: (1) an Exact Multiple-input Binary Accumulator (EMBA), which performs precise binary accumulation, and (2) a Deterministic Threshold-based Scaled Adder (DTSA), which employs threshold logic for scaled addition. These adders are integrated into a multiplier accumulator (MAC) unit supporting both unipolar and bipolar encodings. To validate the framework, we implement two accelerators: a Finite Impulse Response (FIR) filter and an 8-point Discrete Cosine Transform (DCT)/iDCT engine. Results on a 4x4 MAC show that, in unipolar mode, E-HTC matches the RMSE of state-of-the-art Counter-Based Stochastic Computing (CBSC) MAC, improves accuracy by 94% over MUX-based HTC, and reduces power and area by 23% and 7% compared to MUX-based HTC and 64% and 74% compared to CBSC. In bipolar mode, E-HTC MAC achieves 2.09% RMSE -- an 83% improvement over MUX-based HTC -- and approaches CBSC's 1.40% RMSE with area and power savings of 28% and 43% vs. MUX-based HTC and about 76% vs. CBSC. In FIR experiments, both E-HTC variants yield PSNR gains of 3--5 dB (30--45% RMSE reduction) while saving 13% power and 3% area. For DCT/iDCT, E-HTC boosts PSNR by 10--13 dB (70--75% RMSE reduction) while saving area and power over both MUX- and CBSC-based designs.
format Preprint
id arxiv_https___arxiv_org_abs_2509_22999
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Enhanced Hybrid Temporal Computing Using Deterministic Summations for Ultra-Low-Power Accelerators
Sachdeva, Sachin
Lu, Jincong
Li, Wantong
Tan, Sheldon X. -D.
Hardware Architecture
This paper presents an accuracy-enhanced Hybrid Temporal Computing (E-HTC) framework for ultra-low-power hardware accelerators with deterministic additions. Inspired by the recently proposed HTC architecture, which leverages pulse-rate and temporal data encoding to reduce switching activity and energy consumption but loses accuracy due to its multiplexer (MUX)-based scaled addition, we propose two bitstream addition schemes: (1) an Exact Multiple-input Binary Accumulator (EMBA), which performs precise binary accumulation, and (2) a Deterministic Threshold-based Scaled Adder (DTSA), which employs threshold logic for scaled addition. These adders are integrated into a multiplier accumulator (MAC) unit supporting both unipolar and bipolar encodings. To validate the framework, we implement two accelerators: a Finite Impulse Response (FIR) filter and an 8-point Discrete Cosine Transform (DCT)/iDCT engine. Results on a 4x4 MAC show that, in unipolar mode, E-HTC matches the RMSE of state-of-the-art Counter-Based Stochastic Computing (CBSC) MAC, improves accuracy by 94% over MUX-based HTC, and reduces power and area by 23% and 7% compared to MUX-based HTC and 64% and 74% compared to CBSC. In bipolar mode, E-HTC MAC achieves 2.09% RMSE -- an 83% improvement over MUX-based HTC -- and approaches CBSC's 1.40% RMSE with area and power savings of 28% and 43% vs. MUX-based HTC and about 76% vs. CBSC. In FIR experiments, both E-HTC variants yield PSNR gains of 3--5 dB (30--45% RMSE reduction) while saving 13% power and 3% area. For DCT/iDCT, E-HTC boosts PSNR by 10--13 dB (70--75% RMSE reduction) while saving area and power over both MUX- and CBSC-based designs.
title Enhanced Hybrid Temporal Computing Using Deterministic Summations for Ultra-Low-Power Accelerators
topic Hardware Architecture
url https://arxiv.org/abs/2509.22999