Triaxial DC-AC Connection System for Test Instrumentation
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Solution Overview
Problem
Existing interconnection systems for electrical test instrumentation and devices under test (DUTs are cumbersome and costly, particularly when switching between AC and DC tests, as they require frequent changes in connections at the DUT, especially in limited spaces, and do not efficiently support two-cable connection systems which are desirable for high-voltage testing.
Innovation Solution
A two-cable triaxial connection system where the intermediate conductor is allowed to float at higher frequencies, establishing a transmission line between the center and outer conductors, enabling seamless switching between IV, CV, and VNA tests without changing connections at the DUT, using a single pair of triaxial cables with characteristic impedance matching for efficient impedance control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a four-cable connection system is used to support multiple tests, then test versatility is improved, but device complexity and cost increase
Solution Approach 1:
The patent makes the two-cable connection system universal by enabling it to support multiple test types (IV, CV, RF, VNA) through a single configuration. The key mechanism is allowing the intermediate conductor to float at higher frequencies, which automatically establishes the necessary transmission line between center and outer conductors for AC tests, while maintaining DC test capability without requiring additional cables or complex switching.
2Adaptability or versatility
If connections at the DUT are changed to support different test types, then test adaptability is improved, but time between tests increases
Solution Approach 1:
The patent introduces dynamic behavior through the floating intermediate conductor that automatically adapts its state based on frequency. At DC frequencies, the intermediate conductor maintains its traditional role in the triaxial cable structure. At AC frequencies, it naturally floats to establish the transmission line, enabling the same physical connection to serve multiple test types without manual intervention or time loss.
3Device complexity
If a two-cable connection system is used for high-voltage testing, then cost and space requirements are reduced, but impedance control may be compromised
Solution Approach 1:
The patent changes the electrical parameter state of the intermediate conductor from fixed (traditionally connected to guard voltage) to floating at higher frequencies. This parameter change enables the transmission line to form between the center and outer conductors, providing proper impedance control for AC tests while maintaining the simplicity of the two-cable configuration. The characteristic impedance of the transmission line is determined by the cable's physical structure, ensuring measurement precision without additional complexity.
Data Source
AI summary
Embodiments of the present invention provide an improved two-cable connection system for connecting electrical test instrumentation to a device under test (DUT). In one embodiment, a single pair of equal-length triaxial cables each has a desired characteristic impedance. Each cable has a center connecter, intermediate conductor, and outer conductor. The proximal end of each cable is connected to the test instrumentation, and the distal ends are located at the DUT. At the distal end, the center conductors are connected to the DUT, the intermediate conductors are allowed to float, and the outer conductors are connected to each other. The proximal end of each cable is connected to the device using an appropriate connection for the test that will be performed. This allows the test instrumentation to perform different types of tests without changing connections to the DUT.