Neural Network Arithmetic Device with Dynamic Activation Function Circuit

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Solution Overview

Problem

Existing arithmetic devices for neural networks face challenges in efficiently processing and optimizing activation functions, particularly in managing errors and improving accuracy across different input ranges.

Innovation Solution

The proposed arithmetic device incorporates a multiplying-accumulating (MAC) operator and an activation function (AF) circuit with a look-up table. The AF circuit adjusts the number of logic level combinations of the input distribution signal based on the input range of the activation function, using a table input signal generator and an output distribution signal selector to optimize the output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a fixed look-up table is used for activation function processing, then device complexity is reduced, but measurement precision and manufacturing precision deteriorate due to error accumulation across different input ranges

Engineering Contradiction:
Improveactivation function circuit complexityVSAvoidactivation function accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The activation function input range is divided into multiple segments or regions. Each segment has its own optimized look-up table or processing parameters. This segmentation allows the system to maintain high precision across the entire input range by treating each segment with specialized handling, rather than using a single fixed table that must compromise for all ranges.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The look-up table structure is made dynamic by adjusting the number of logic level combinations based on the input range. The system dynamically selects or configures different table configurations depending on the current input distribution, allowing optimization for each specific range while maintaining overall system accuracy.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If the number of logic level combinations is uniformly distributed, then device complexity is minimized, but manufacturing precision worsens due to error variations across different input ranges

Engineering Contradiction:
Improvelogic level combination managementVSAvoidactivation function output accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

Different input ranges are assigned different numbers of logic level combinations based on their error characteristics. Ranges with higher error rates receive more logic level combinations for finer granularity and better precision, while ranges with lower error rates use fewer combinations. This local optimization approach improves overall accuracy without uniformly increasing complexity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system changes the parameter of logic level combination count based on the input range being processed. By dynamically adjusting this parameter according to the specific input distribution and error characteristics of each range, the system optimizes precision for each segment while managing overall complexity.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If a simplified activation function processing method is used, then productivity is improved, but measurement precision deteriorates due to increased error rates

Engineering Contradiction:
Improveneural network processing speedVSAvoidactivation function accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The system applies partial precision optimization by using variable numbers of logic level combinations only where needed - specifically in input ranges that exhibit higher error rates. For ranges with acceptable error margins, a simpler processing approach is used. This selective application of complexity maintains high productivity while improving precision only where necessary.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS20250181317A1Arithmetic devices for neural network
Publication Date: 2025.06.05 SK HYNIX INC
  • US20250181317A1 patent drawing
  • US20250181317A1 patent drawing
  • US20250181317A1 patent drawing

AI summary

An arithmetic device includes a multiplying-accumulating (MAC) operator and an activation function (AF) circuit. The MAC operator performs a MAC arithmetic operation for weight data and vector data to generate an arithmetic result signal. The AF circuit stores a look-up table for an activation function, adjusts a number of logic level combinations of an input distribution signal that correspond to each logic level combination of the output distribution signal, among a plurality of logic level combinations of the output distribution signal, based on an input range of the activation function. The AF circuit selects and outputs the output distribution signal that corresponds to the input distribution signal based on the look-up table. The input range of the activation function is based on a relative number of errors that occur.