Mixed-Signal Bitwise Multiplication With Split Accuracy

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Solution Overview

Problem

Mixed signal circuit designs face limitations due to the energy constraints of analog-to-digital conversion (ADC) in performing computations, particularly in neural network workloads where matrix multiplications are energy-inefficient in the digital domain but more efficient in the analog domain.

Innovation Solution

Implementing mixed signal multiply-accumulate (MS-MAC) circuitry that combines digital and analog processing to perform bitwise multiplication with varying accuracies, using different architectures for different dot product engines based on noise contributions to enhance computation accuracy and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If ADC conversion is used to perform computations in mixed signal circuitry, then digital computation capability is achieved, but energy consumption increases significantly

Engineering Contradiction:
Improvecomputation capabilityVSAvoidADC conversion energy
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The patent segments the multiplication computation into two distinct portions: a first portion performed with higher accuracy and a second portion performed with lower accuracy. This segmentation allows the system to allocate computational resources differently across different parts of the same operation, reducing overall energy consumption while maintaining necessary precision for critical calculations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by using different accuracy levels for different portions of the multiplication operation. The first portion uses higher accuracy (more bits) where precision is critical, while the second portion uses lower accuracy (fewer bits) where approximate results are sufficient. This non-uniform quality distribution optimizes the trade-off between computation capability and energy consumption.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If uniform high accuracy is used for all bitwise multiplication portions, then computation precision is maximized, but energy consumption and circuit complexity increase

Engineering Contradiction:
Improvemultiplication accuracyVSAvoidcomputation energy
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent implements local quality by assigning different accuracy levels to different portions of the multiplication operation. The first portion is computed with higher accuracy using more bits, while the second portion uses lower accuracy with fewer bits. This approach maintains necessary precision for critical calculations while reducing energy consumption and circuit complexity for less critical portions.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent divides the multiplication operation into two segments with different accuracy requirements. This segmentation allows the system to apply high precision only where necessary and use lower precision elsewhere, optimizing the balance between measurement precision and energy consumption.

Inventive Principle:
Principle #1Segmentation

3Device complexity

If all bitwise multiplication portions are performed with the same accuracy, then circuit design is simplified, but noise and bit errors increase in mixed-signal domain

Engineering Contradiction:
Improvecircuit design complexityVSAvoidcomputation reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies local quality by using different accuracy levels for different portions of the multiplication operation. This differential approach reduces noise and bit errors in the mixed-signal domain by ensuring that critical portions are computed with sufficient precision while allowing non-critical portions to use lower precision, thereby improving overall computation reliability.

Inventive Principle:
Principle #3Local quality

4Reliability

If higher accuracy is used for all multiplication operations, then noise and bit errors are reduced, but energy consumption increases

Engineering Contradiction:
Improvecomputation reliabilityVSAvoidcomputation energy
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements local quality by assigning different accuracy levels to different portions of the multiplication operation. Critical portions that require high reliability are computed with higher accuracy, while non-critical portions use lower accuracy. This selective approach reduces noise and bit errors where necessary while minimizing energy consumption overall.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent segments the multiplication operation into portions with different reliability requirements. By computing only the critical portions with high accuracy and using lower accuracy for non-critical portions, the system achieves the necessary computation reliability without the prohibitive energy cost of uniformly high-precision computation throughout.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS20230083270A1Mixed signal circuitry for bitwise multiplication with different accuracies
Publication Date: 2023.03.16 INTERNATIONAL BUSINESS MACHINE CORPORATION
  • US20230083270A1 patent drawing
  • US20230083270A1 patent drawing
  • US20230083270A1 patent drawing

AI summary

An apparatus comprises at least one processor and at least one memory including instruction code configured to, with the at least one processor, cause the apparatus at least to perform, with a first accuracy, a first portion of a bitwise multiplication of first and second digital inputs and to perform, with a second accuracy different than the first accuracy, at least a second portion of the bitwise multiplication.