RFID Circuit Self-Testing via DC Trigger Signals
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Solution Overview
Problem
Existing RFID systems, particularly Ultra High Frequency (UHF) systems, face challenges in performing functional tests on integrated circuits after they have been separated from wafers and bonded to substrates, as the conventional RF-based testing methods are costly and prone to damaging the circuits, and do not allow for triggering self-tests using non-RF voltages.
Innovation Solution
A circuit design that includes test trigger signal detecting means to recognize a DC or low-frequency signal, allowing for the performance of functional tests without RF signal generation equipment, using direct current signals for testing, which are cheaper and less prone to environmental noise, and do not require additional pads or connectors, while maintaining RF operational capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RF-based testing methods are used to test integrated circuits after separation from wafers, then functional testing can be performed, but the testing equipment becomes costly and the circuits become prone to damage
Solution Approach 1:
The patent replaces the RF-based testing system with a DC voltage-based testing system. Instead of using complex RF signal generation and detection equipment, the invention uses simple DC voltage sources applied through existing circuit points to trigger self-tests within the integrated circuit. This substitution dramatically simplifies the testing equipment while maintaining effective functional testing capability.
Solution Approach 2:
The integrated circuit performs self-testing automatically when DC voltage is applied to its circuit points. The circuit contains internal testing means that are activated by the DC voltage, allowing the circuit to test itself without requiring external RF testing equipment. This self-service approach eliminates the need for complex external testing systems.
2Adaptability or versatility
If conventional RF testing is used, then circuits can be tested before wafer separation, but testing cannot be performed after separating and bonding circuits to substrates
Solution Approach 1:
The DC voltage-based testing method is universally applicable across all manufacturing stages including before wafer separation, after separation, and after bonding to substrates. The same simple DC testing apparatus can be used throughout the entire manufacturing process, making the testing system highly versatile and eliminating the limitation of time-sensitive testing windows.
3Measurement precision
If RF signals are used for triggering self-tests, then wireless activation is possible, but the testing becomes susceptible to environmental noise
Solution Approach 1:
The patent substitutes RF signal-based triggering with DC voltage-based triggering. DC voltage signals are inherently immune to environmental noise such as electromagnetic interference that affects RF signals. This substitution significantly improves measurement precision by eliminating noise susceptibility while maintaining the ability to trigger self-tests effectively.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables cost-effective and reliable self-testing of RFID circuits without affecting their RF operation, providing immunity to noise and allowing for simpler test equipment, with successful tests indicated by modulated response signals, and enabling power supply via both RF and DC signals.
Implementation Method 1
test trigger signal detecting means being designed for detecting a direct current component of a test trigger signal that is applied across the first circuit point and the second circuit point
Implementation Method 2
RF transmission means being designed for receiving in a contact-less manner an AC carrier signal from a read/write station
Data Source
AI summary
A circuit (12) comprises a first circuit point (13) and a second circuit point (14), which first circuit point (13) and second circuit point (14) are designed to be connected with RF transmission means (11) being designed for receiving in a contact-less manner a carrier signal (CS) from a read/write station and for feeding the circuit (12) with the received carrier signal (CS). The circuit (12) further comprises circuit testing means (4) being designed to carry out functional tests of the circuit (12) and to output a modulated response signal (TS-MOD) via the first and second circuit points (13, 14) only if the functional tests have been successful. The circuit (12) further comprises test trigger signal detecting means (5) being designed for detecting a test trigger signal (TS) that is applied across the first circuit point (13) and the second circuit point (14), wherein the test trigger signal detecting means (5) are designed to trigger the circuit testing means (4) to carry out the functional tests if they detect the test trigger signal (TS).