Hardware-Software Co-Design of Scalable, Energy-Efficient Analog Recurrent Computations

Fuente: arXiv
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Auteurs principaux: Fyon, Arthur, Brandoit, Julien, Mendolia, Loris, Ernst, Damien, Redouté, Jean-Michel, Drion, Guillaume
Format: Preprint
Publié: 2026
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author Fyon, Arthur
Brandoit, Julien
Mendolia, Loris
Ernst, Damien
Redouté, Jean-Michel
Drion, Guillaume
author_facet Fyon, Arthur
Brandoit, Julien
Mendolia, Loris
Ernst, Damien
Redouté, Jean-Michel
Drion, Guillaume
contents Always-on AI applications, from environmental sensors to biomedical implants, require ultra-low power consumption. Analog circuits offer a path to sub-microwatt inference, yet existing analog implementations are limited to feedforward architectures: extending them to recurrent dynamics has been considered impractical due to noise accumulation through temporal feedback. We demonstrate that this barrier can be overcome through hardware-software co-design. Specifically, we identify that Bistable Memory Recurrent Units (BMRUs), a class of Recurrent Neural Networks (RNNs) with discrete-valued outputs and hysteretic dynamics, admit an ultra-low power current-mode analog implementation which we design from first principles. The resulting circuit establishes a one-to-one correspondence between each learned parameter and a circuit element. The discrete outputs suppress analog noise by at least 20-fold at each cell boundary, breaking the noise accumulation that prevents analog recurrence. We reformulate BMRUs for first-quadrant operation with fixed thresholds, enabling the direct correspondence while preserving expressivity and trainability. Transistor-level simulations in 180 nm Complementary Metal-Oxide-Semiconductor (CMOS) show near-perfect agreement between software predictions and circuit-level behavior, with the software model thereby serving as a high-fidelity simulator of the physical hardware at low computational cost. We leverage this fidelity to conduct large-scale noise immunity and power scaling analyses: the power cost of adding recurrence scales linearly with state dimension, while the feedforward layers dominating total power scale quadratically, meaning recurrence is added at linear marginal cost relative to the feedforward backbone. End-to-end keyword spotting achieves sub-microwatt inference at the RNN core.
format Preprint
id arxiv_https___arxiv_org_abs_2605_15216
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Hardware-Software Co-Design of Scalable, Energy-Efficient Analog Recurrent Computations
Fyon, Arthur
Brandoit, Julien
Mendolia, Loris
Ernst, Damien
Redouté, Jean-Michel
Drion, Guillaume
Hardware Architecture
Machine Learning
Always-on AI applications, from environmental sensors to biomedical implants, require ultra-low power consumption. Analog circuits offer a path to sub-microwatt inference, yet existing analog implementations are limited to feedforward architectures: extending them to recurrent dynamics has been considered impractical due to noise accumulation through temporal feedback. We demonstrate that this barrier can be overcome through hardware-software co-design. Specifically, we identify that Bistable Memory Recurrent Units (BMRUs), a class of Recurrent Neural Networks (RNNs) with discrete-valued outputs and hysteretic dynamics, admit an ultra-low power current-mode analog implementation which we design from first principles. The resulting circuit establishes a one-to-one correspondence between each learned parameter and a circuit element. The discrete outputs suppress analog noise by at least 20-fold at each cell boundary, breaking the noise accumulation that prevents analog recurrence. We reformulate BMRUs for first-quadrant operation with fixed thresholds, enabling the direct correspondence while preserving expressivity and trainability. Transistor-level simulations in 180 nm Complementary Metal-Oxide-Semiconductor (CMOS) show near-perfect agreement between software predictions and circuit-level behavior, with the software model thereby serving as a high-fidelity simulator of the physical hardware at low computational cost. We leverage this fidelity to conduct large-scale noise immunity and power scaling analyses: the power cost of adding recurrence scales linearly with state dimension, while the feedforward layers dominating total power scale quadratically, meaning recurrence is added at linear marginal cost relative to the feedforward backbone. End-to-end keyword spotting achieves sub-microwatt inference at the RNN core.
title Hardware-Software Co-Design of Scalable, Energy-Efficient Analog Recurrent Computations
topic Hardware Architecture
Machine Learning
url https://arxiv.org/abs/2605.15216