Hysteresis IC Testing via Sub-Threshold Voltage Waveforms
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for testing circuits with hysteresis are time-consuming and costly, especially when dealing with large numbers of device packages in production, as they require sweeping input voltages to determine high and low trigger points, which is inefficient for high-coverage testing.
Innovation Solution
A test system that generates specific input voltage waveforms with transitions between expected trigger points and sub-threshold voltage levels to efficiently verify the operation of integrated circuits with hysteresis, using characterization studies to determine tolerable voltage differences and reduce testing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional voltage sweeping methods are used to test circuits with hysteresis, then measurement precision of trigger points is improved, but testing time increases significantly
Solution Approach 1:
The patent performs preliminary characterization of the hysteresis circuit to establish expected trigger points and sub-threshold values before actual testing. These pre-determined values are stored and used during production testing, eliminating the need for time-consuming voltage sweeping during each test. The preliminary characterization action is performed once, and the results are reused for multiple tests.
Solution Approach 2:
The patent creates a digital copy of the expected trigger points and sub-threshold values from characterization studies. These copied values are stored in memory and compared against actual measurements during testing, replacing the need to re-perform the time-consuming voltage sweeping procedure for each test.
2Reliability
If comprehensive testing of all trigger points is performed, then reliability of testing is improved, but productivity decreases
Solution Approach 1:
The patent applies partial action by testing only the critical trigger points and sub-threshold values that are most likely to fail, rather than performing comprehensive voltage sweeping across all possible values. The characterization studies identify the critical thresholds, and testing focuses on verifying these specific points, achieving sufficient reliability without the full cost of exhaustive testing.
Solution Approach 2:
The patent changes the testing parameters from continuous voltage sweeping to discrete testing at specific predetermined points (expected trigger points and sub-threshold values). This parameter transformation from continuous to discrete testing maintains reliability for the critical thresholds while dramatically improving testing speed and productivity.
3Productivity
If high-speed testing equipment is used, then productivity is improved, but cost increases
Solution Approach 1:
The patent enables the device under test to essentially test itself by using its own expected characteristics (trigger points and sub-threshold values) as the test criteria. The device's inherent hysteresis behavior is exploited to create self-diagnostic capability, eliminating the need for complex external testing equipment and reducing both cost and complexity while maintaining high productivity.
Data Source
AI summary
A system and method for testing circuits. A generated input voltage waveform for a first phase of a test may use transitions with a voltage swing between expected low and high trigger points for an integrated circuit (IC) with hysteresis. A generated input voltage waveform for a second phase of the test may use transitions with a voltage swing between the expected low trigger point and a high sub-threshold value. The high sub-threshold value may be a tolerable voltage difference below the expected high trigger point. A generated input voltage waveform for a third phase of the test may use transitions with a voltage swing between the expected high trigger point and a low sub-threshold value. The low sub-threshold value may be a tolerable voltage difference above the expected low trigger point. The expected trigger points and sub-threshold values may be found from earlier characterization studies for the IC.