Tunable Floating-Point MACs with Selective Sub-Multiplier Activation

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Solution Overview

Problem

Existing MAC designs in deep learning accelerators face inefficiencies due to fixed precision requirements, leading to high energy consumption and inflexibility between bit-parallel and bit-serial approaches, with bit-parallel designs often processing more bits than needed and bit-serial approaches introducing latency and data movement constraints.

Innovation Solution

A tunable floating-point MAC unit that partitions operands into segments, enabling selective activation of sub-multipliers based on exponent differences to dynamically adjust precision and reduce energy consumption without architectural changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If bit-parallel MAC designs are used to maintain high performance and precision, then computation speed and accuracy are improved, but energy consumption increases due to processing more bits than needed

Engineering Contradiction:
Improvecomputation speedVSAvoidenergy consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic precision adjustment in bit-parallel MAC units by enabling/disabling sub-multipliers based on exponent differences. The system transitions from static fixed-precision architecture to dynamic variable-precision architecture, allowing the MAC unit to adapt its computational precision to actual task requirements, thereby reducing energy consumption when high precision is not needed while maintaining performance when required

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent divides the multiplier into multiple sub-multipliers that process different bit segments of the operands independently. This segmentation allows selective activation of sub-multipliers based on precision requirements, enabling the system to process only the necessary number of bits for each computation, thus reducing overall energy consumption while maintaining acceptable computational performance

Inventive Principle:
Principle #1Segmentation

2Use of energy by moving object

If bit-serial approaches are used to reduce energy consumption and adjust precision dynamically, then energy efficiency is improved, but latency increases and data movement constraints are introduced

Engineering Contradiction:
Improveenergy efficiencyVSAvoidlatency
Core Design Contradiction:
Use of energy by moving objectVSLoss of time

Solution Approach 1:

The patent segments the multiplication operation into parallel sub-multiplier units that can operate simultaneously on different bit segments. This parallel segmentation eliminates the sequential bottleneck of bit-serial approaches, allowing the system to achieve both energy efficiency through selective activation and low latency through parallel processing

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent combines dynamic precision adjustment capability with parallel bit-parallel architecture. By dynamically enabling or disabling sub-multipliers based on exponent differences while maintaining parallel processing capability, the system achieves energy efficiency without introducing the latency penalties associated with bit-serial approaches

Inventive Principle:
Principle #15Dynamics

3Device complexity

If fixed precision MAC units are used to simplify architecture, then device complexity is reduced, but adaptability to different precision requirements deteriorates

Engineering Contradiction:
Improvearchitecture simplicityVSAvoidprecision adaptability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent segments the multiplier into multiple sub-multipliers with uniform structure, allowing the same hardware architecture to support variable precision by selectively activating different segments. This segmentation approach maintains architectural simplicity while enabling adaptability, as the control logic simply needs to enable or disable appropriate sub-multipliers based on precision requirements

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent designs a universal MAC unit architecture where a single set of sub-multipliers can serve multiple precision requirements. The same hardware structure performs both high-precision and low-precision computations by dynamic activation patterns, eliminating the need for multiple dedicated MAC units with different fixed precisions

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentUS20250328311A1Systems and methods for energy-efficient, bit-parallel, multiply-accumulate for artificial intelligence and deep neural networks
Publication Date: 2025.10.23 KAXIRAS STEFANOS
  • US20250328311A1 patent drawing
  • US20250328311A1 patent drawing
  • US20250328311A1 patent drawing

AI summary

A system and method for providing a tunable floating-point multiply-accumulate (MAC) unit are disclosed. The unit maintains full arithmetic precision while enabling dynamic elimination of ineffectual computation through operand decomposition and selective activation of partial product generation logic. The disclosed MAC unit is suitable for drop-in replacement in existing deep-learning accelerators and improves energy efficiency without requiring architectural changes.