Power-Aware Dynamic Encoding for Scan Test Compression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current design-for-test (DFT) methodologies in electronic design automation (EDA) tools face challenges in minimizing test data volume and power dissipation during the test mode, particularly due to limitations in decompressor schemes that affect the efficiency of test data compression and the toggling rate in scan-in operations.
Innovation Solution
The proposed solution involves an EDA tool that incorporates design-for-test circuitry with a power-aware decompressor scheme, utilizing a combination of static and dynamic test stimulus sources and programmable controllers to selectively enable dynamic test stimuli, reducing toggling rates and power consumption by grouping scan cells and using circular registers to generate decompressed test stimuli based on superpositions of static and dynamic test sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dynamic test stimulus sources are used to improve test coverage and encoding efficiency, then test coverage and encoding efficiency are improved, but power consumption and toggling rates increase
Solution Approach 1:
The patent implements a hybrid decompressor that dynamically switches between static and dynamic test stimulus sources based on the specific test requirements. The system uses programmable controllers to selectively enable dynamic test stimuli only when needed for specific scan cells, rather than applying dynamic stimulation universally. This dynamic adaptation allows the system to optimize between test coverage and power consumption on a per-scan-cell basis.
Solution Approach 2:
The patent applies different test stimulus characteristics to different groups of scan cells based on their specific testing requirements. By dividing scan cells into groups and applying dynamic stimulation only to specific groups that require it, the system achieves high test coverage where needed while minimizing power consumption in areas where static stimulation suffices. This localized approach to test stimulus application resolves the contradiction between comprehensive testing and power efficiency.
2Quantity of substance
If decompressor schemes are used to compress test data volume, then test data volume is reduced, but power dissipation during test mode increases due to higher toggling rates
Solution Approach 1:
The hybrid decompressor dynamically adjusts the level of compression and stimulation based on the specific test requirements. Rather than applying maximum compression uniformly, the system adaptively selects between static and dynamic decomposition modes, enabling high compression ratios where applicable while reducing toggling activity to minimize power dissipation during test operations.
Solution Approach 2:
The patent changes the operational parameters of the decompressor by selectively enabling dynamic test stimuli for specific scan cell groups while maintaining static stimulation for others. This parameter adjustment allows the system to optimize the balance between compression efficiency and power dissipation, achieving significant test data volume reduction without incurring the full power penalty of universal dynamic stimulation.
3Productivity
If high encoding efficiency is achieved through dynamic encoding, then test application efficiency is improved, but overheating and supply voltage noise increase
Solution Approach 1:
The system dynamically controls the application of test stimuli to achieve high encoding efficiency only where and when necessary. By using programmable controllers to selectively enable dynamic test stimuli for specific scan cells rather than applying it universally, the system maintains high test application efficiency for critical areas while limiting the generation of harmful effects like overheating and voltage noise to minimal necessary levels.
Data Source
AI summary
Dynamic power-aware encoding method and apparatus is presented based on a various embodiments described herein. The experimental results confirmed that a desirable reduction in the toggling rate in the decompressed test stimulus is achievable by reasonable overhead (ATPG time, hardware overhead and pattern inflation) typically without degradation of a compression ratio. The performed experimental evaluation confirms that the described embodiments can support aggressive scan compression, efficient dynamic pattern compaction and a reduction of toggling rate in the decompressed test stimulus.