TMR Flip-Flop Test Mode With State Restoration
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Solution Overview
Problem
Existing triple modular redundancy (TMR) systems face challenges in performing fault detection during operation without disrupting the normal functioning of integrated circuits, as built-in self-tests (LBIST) result in loss of information and inability to resume operation in the previous state post-test.
Innovation Solution
A method and architecture that utilize a majority vote circuit with an odd number of flip-flops, allowing for a test mode where one flip-flop is tested while others are frozen, with automatic restoration of the previous state after the test, enabling fault detection without disrupting normal operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a built-in self-test (LBIST) is performed during operation of the integrated circuit, then fault detection capability is improved, but the information contained in each electronic component is lost and the circuit cannot continue operation in its previous state
Solution Approach 1:
The integrated circuit is divided into multiple independent electronic components (first, second, and third components) that can be tested individually. Each component can be placed into test mode independently while others continue normal operation, allowing fault detection without complete system shutdown or information loss.
Solution Approach 2:
The test mode is applied locally to only the electronic component being tested, while other components maintain their normal operational state. This localized testing approach allows fault detection in one component without affecting the operational state or information in other components.
2Reliability
If triple modular redundancy (TMR) is implemented to reduce error probability, then reliability is improved, but device complexity increases due to replication of circuits
Solution Approach 1:
The electronic components are designed to serve multiple functions: they operate in normal mode during regular circuit operation and can be switched to test mode for fault detection. This multi-functionality allows the same hardware to provide both operational and diagnostic capabilities without requiring separate dedicated test circuits.
Solution Approach 2:
The electronic components can dynamically switch between normal operational mode and test mode based on control signals. This dynamic capability allows the system to adapt its behavior for different operational requirements without permanent structural changes or additional complexity.
Data Source
AI summary
A method for managing operation of a logic component is provided, with the logic component including a majority vote circuit and an odd number of flip-flops equal to at least three. The method includes, following a normal operating mode of the logic component, placing a flip-flop in a test mode, and injecting a test signal into a test input of the flip-flop being tested while a logic state of the other flip-flops is frozen. A test signal output is analyzed. At the end of the test, the logic component is placed back in the normal operating mode. The majority vote circuit restores a value of the output signal from the logic component that existed prior to initiation of the test.