MBIST Adaptive Port for Non-Destructive In-Field Memory Testing
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Solution Overview
Problem
Current memory testing technologies, such as MBIST, cannot be performed in-field during operational mode due to the lengthy testing time required, which disrupts system operation and is destructive to stored data.
Innovation Solution
A BIST adaptive port (BAP) interface enables non-destructive in-field memory testing by storing operational data in registers during testing, allowing periodic testing without disrupting system functionality and enabling predictive error repair.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MBIST testing is performed on memory addresses, then fault detection capability is improved, but testing time becomes too long to fit within acceptable testing window
Solution Approach 1:
The patent divides the memory testing process into segments by implementing periodic in-field testing that operates on subsets of memory addresses rather than testing all addresses continuously. The testing is performed in periodic intervals during normal system operation, allowing fault detection capability to be maintained while fitting testing within acceptable time windows during operational mode.
Solution Approach 2:
The patent implements periodic testing where MBIST operations are performed at regular intervals during normal system operation rather than requiring continuous or exhaustive testing. This periodic approach allows the system to maintain reliability through regular fault detection while keeping individual testing windows short enough to fit within acceptable time constraints during operational mode.
2Reliability
If MBIST testing is performed on memory locations, then fault detection capability is improved, but operational data stored in memory is destroyed
Solution Approach 1:
The patent introduces an intermediary mechanism where operational data to be tested is first copied to a buffer or temporary storage location before MBIST testing is performed. This intermediary step allows the testing process to access and test the data without directly manipulating the original operational data in memory, thereby preventing data destruction while maintaining fault detection capability.
Solution Approach 2:
The patent implements a copying approach where data from operational memory locations is copied to a separate buffer or temporary storage area before testing. The MBIST operations then test this copied data rather than the original operational data, ensuring that any testing operations cannot destroy the actual operational data while still enabling comprehensive fault detection through algorithmic testing.
3Reliability
If memory testing is performed after system build and before deployment, then testing can be completed thoroughly, but system operational mode testing is not possible
Solution Approach 1:
The patent implements a universal testing approach where the MBIST controller and testing algorithms are designed to function in multiple modes: both pre-deployment testing mode and in-field operational mode. The same testing infrastructure and algorithms can be used whether the system is being tested before deployment or during operational mode, providing versatility while maintaining testing completeness through the use of comprehensive test patterns and algorithms.
Solution Approach 2:
The patent implements dynamic testing capability where the MBIST system can adapt its operation based on the system state. The testing can be initiated, paused, or configured differently depending on whether the system is in pre-deployment or operational mode. This dynamic approach allows thorough testing to be performed in both contexts by adjusting the testing parameters and timing to match the operational requirements of each mode.
Data Source
AI summary
A BIST (built-in self-test) adaptive port (BAP) interface enables an in-field MBIST (memory BIST). The BAP enables non-destructive testing of the memory locations. The BAP includes registers to store contents of the memory device during the in-field MBIST on the memory device. The BAP can store the starting address of the next infield periodic testing and operational data from a selected memory address in the registers while the MBIST controller performs the test on the memory address. The system can then restore the operational contents of the memory after the test is complete.