Integrated Circuit Online Testing via Activity Detection
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Solution Overview
Problem
Integrated circuits, especially in safety-critical systems, may malfunction due to wear or particle damage after manufacturing tests, as existing serial scan chain testing methods are ineffective for identifying issues during operational use.
Innovation Solution
Incorporating activity detection circuitry to identify inactive functional circuits within integrated circuits, allowing for 'online' scan testing during normal operation without disrupting functionality, using serial scan chains and error detection circuitry to identify and address errors without switching to a test mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If serial scan chain testing is performed using traditional methods, then manufacturing defects can be identified, but the integrated circuit cannot be tested during operational use and may fail due to wear or particle damage
Solution Approach 1:
The serial scan chains are designed to serve dual purposes: traditional manufacturing testing and online operational testing. The same scan chain infrastructure is used for both ATP (Automatic Test Pattern) generation during manufacturing and functional monitoring during operation, eliminating the need for separate testing mechanisms and reducing overall device complexity.
Solution Approach 2:
Activity detection circuitry is introduced as an intermediary component that monitors functional circuit activity and triggers scan chain operations only when circuits are inactive. This mediator enables the integration of testing capabilities without requiring complex control logic, as the activity detection circuitry naturally coordinates between operational status and testing requirements.
2Reliability
If the integrated circuit switches to test mode for scanning, then functional circuits can be tested, but data processing operations are interrupted
Solution Approach 1:
The testing system dynamically adapts to the operational state of functional circuits by continuously monitoring activity signals. Scan chain operations are initiated only when activity detection circuitry determines that a functional circuit is inactive, ensuring that testing occurs naturally during idle periods without interrupting data processing operations. This dynamic coordination maintains productivity while enabling continuous reliability monitoring.
3Reliability
If scan testing is performed continuously on all functional circuits, then comprehensive error detection is achieved, but power consumption increases excessively
Solution Approach 1:
Instead of continuous testing, the system employs periodic scan operations triggered by activity detection. Functional circuits are tested only during their inactive periods when they would naturally be idle anyway. This periodic approach, coordinated with the operational cycles of functional circuits, maintains comprehensive error detection coverage while avoiding the excessive power consumption that would result from continuous testing of all circuits regardless of their operational state.
4Productivity
If multiple functional circuits are tested simultaneously, then testing efficiency is improved, but coordination complexity and potential interference increase
Solution Approach 1:
The testing system segments the functional circuits into multiple groups, each with its own dedicated scan chain. This segmentation allows simultaneous testing of multiple circuits without requiring complex coordination between shared resources. Each scan chain operates independently on its assigned functional circuit, eliminating interference and reducing control complexity while maintaining high testing efficiency through parallel operation.
Data Source
AI summary
An integrated circuit 2 provided with multiple functional units 6, 8, 10, 12, 14, and 16 for performing data processing operations as part of advancing execution of a data processing task by the integrated circuit 2. Activity detection circuitry 26 determines which of these functional circuits is inactive at the given time. If a functional is inactive, then scan control circuitry 28 may perform a scan test operation thereon using an associated serial scan chain 34, 36, 38, 40, 42, 44.