Variable-Bit Neural Engine Circuit for Lower Power AI Compute

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Solution Overview

Problem

Existing neural network computations consume significant CPU bandwidth and power due to extensive operations, affecting the performance and speed of electronic devices.

Innovation Solution

A neural engine circuit with multiple multiply circuits operating in different modes to adjust bit width dynamically, allowing parallel and combined computations for efficient power and bandwidth management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If CPU and main memory are used to instantiate and execute machine learning systems, then ease of configuration and instantiation is improved, but CPU bandwidth consumption and power consumption increase significantly

Engineering Contradiction:
Improveease of configurationVSAvoidpower consumption
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The system divides the machine learning execution into two segments: configuration management handled by the CPU (maintaining ease of configuration) and actual computational operations handled by the neural engine circuit (reducing CPU bandwidth and power consumption). The neural engine circuit includes dedicated multiply circuits that perform computations independently of the CPU.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A buffer circuit is introduced as an intermediary between the CPU and the neural engine circuit. The buffer circuit receives configuration data from the CPU and feeds input data to the neural engine circuit, allowing the CPU to offload computational tasks while maintaining configuration flexibility through software updates.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If CPU and main memory are used to execute machine learning operations, then flexibility in model instantiation is improved, but overall device performance and computation speed deteriorate

Engineering Contradiction:
Improveflexibility in model instantiationVSAvoidcomputation speed
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The system segments functionality so that the neural engine circuit is dedicated to high-speed computation while the CPU maintains flexibility for configuration. The neural engine circuit includes multiple multiply circuits that can process data in parallel, significantly increasing computation speed compared to CPU-only execution.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The neural engine circuit is designed with multiple multiply circuits that can operate in different modes (first mode with first bit width, second mode with second bit width), providing versatility for different computational requirements while maintaining high performance. This multi-functionality allows the same hardware to handle various machine learning operations efficiently.

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

3Productivity

If multiple multiply circuits operate in parallel to increase computation speed, then productivity is improved, but device complexity increases

Engineering Contradiction:
Improvecomputation speedVSAvoidcircuit complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

Multiple multiply circuits are merged into a single neural engine circuit that can operate in different modes. In the first mode, multiple multiply circuits operate independently in parallel to process multiple data elements simultaneously. In the second mode, the same circuits operate as a combined computation circuit for higher bit width operations. This merging approach achieves high productivity without proportionally increasing overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentUS12505338B2Dynamic variable bit width neural processor
Publication Date: 2025.12.23 APPLE INC
  • US12505338B2 patent drawing
  • US12505338B2 patent drawing
  • US12505338B2 patent drawing

AI summary

Embodiments relate to an electronic device that includes a neural processor having multiple neural engine circuits that operate in multiple modes of different bit width. A neural engine circuit may include a first multiply circuit and a second multiply circuit. The first and second multiply circuits may be combined to work as a part of a combined computation circuit. In a first mode, the first multiply circuit generates first output data of a first bit width by multiplying first input data with a first kernel coefficient. The second multiply circuit generates second output data of the first bit width by multiplying second input data with a second kernel coefficient. In a second mode, the combined computation circuit generates third output data of a second bit width by multiplying third input data with a third kernel coefficient.