NPU Runtime Function Testing for Defect Isolation
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Solution Overview
Problem
Neural processing units (NPUs) in critical systems like autonomous vehicles and drones may operate erratically due to minor defects not detected during pre-shipment testing, which can be exacerbated by fatigue or physical stress, leading to unpredictable AI outcomes.
Innovation Solution
A method for performing runtime tests on NPUs, utilizing a component tester to scan test functional components, including memory instances and processing elements, to detect defects and isolate faulty components, ensuring continued operation and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pre-shipment testing is performed on NPU components, then manufacturing defects can be detected, but minor or minute defects may remain undetected and cause erratic operation during runtime
Solution Approach 1:
The patent applies preliminary action by implementing runtime testing capabilities that continuously monitor and test NPU components during operation. The test controller is pre-configured to perform scan tests on functional components, detecting defects that pre-shipment testing missed. This proactive approach catches minor defects before they cause erratic AI operation in mission-critical systems.
Solution Approach 2:
The patent implements feedback by creating a closed-loop testing system where the test controller continuously monitors functional components during runtime, compares test results against expected behavior, and identifies defects in real-time. This feedback mechanism enables the system to detect and report minor defects that escaped pre-shipment testing, improving overall reliability through continuous verification.
2Reliability
If scan test is performed on first group of memory instances, then defects in those memory instances can be detected, but the NPU operation may be interrupted
Solution Approach 1:
The patent applies segmentation by dividing memory instances into multiple groups (first group, second group, third group) that can be tested independently. The test controller selectively applies scan tests to specific groups based on operational requirements. This segmentation allows defect detection in targeted memory groups without requiring complete system shutdown, maintaining productivity while ensuring reliability.
Solution Approach 2:
The patent implements periodic action by scheduling scan tests on different memory instance groups at different runtime intervals. Instead of testing all memory instances simultaneously (which would interrupt operation), the system periodically tests specific groups when operational demands allow, balancing defect detection needs with continuous productivity requirements.
3Reliability
If multiple functional components are tested simultaneously, then defect detection coverage is improved, but system complexity and test coordination difficulty increase
Solution Approach 1:
The patent applies segmentation by organizing functional components into distinct testable groups under a hierarchical test controller structure. Each group can be tested independently or in coordinated sequences, reducing the complexity of simultaneous multi-component testing. The test controller manages these segmented groups through structured test protocols, achieving comprehensive coverage without overwhelming system complexity.
Data Source
AI summary
A neural processing unit (NPU) for testing a component during runtime is provided. The NPU may include a plurality of functional components including a first functional component and a second functional component. At least one of the plurality of functional components may be driven for calculation of an artificial neural network. Another one of the plurality of functional components may be selected as a component under test (CUT). A scan test may be performed on the at least one functional component selected as the CUT. A tester for detecting a defect of an NPU is also provided. The tester may include a component tester configured to communicate with at least one functional component of the NPU, select the at least one functional component as a CUT, and perform a scan test for the selected CUT.