A test strategy for a current source designed for fast field-cycling nuclear magnetic resonance

Abstract

This article presents a novel structural test strategy for a single MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) source designed for Fast Field-Cycling Nuclear Mag-netic Resonance (FFC-NMR) systems. The proposed methodolo-gy enables in-field fault detection during idle intervals or before experiment initiation, a critical step to ensure the reliability and validity of the experimental outcomes. The circuit under test is divided into two sections: low-power and high-power. Each one is evaluated using tailored analog testing techniques: OBT (Oscilla-tion-Based Test) and direct current testing are applied to the low-power section, while transient analysis with DTW (Dynamic Time Warping) is used for fault detection in the high-power section. This approach achieves high fault coverage—93.7% for the low-power section and 100% for the high-power section—without requiring complex signal processing. The effectiveness of the method is validated through simulation studies complemented by experimental fault injection on a scaled-down prototype. The results demonstrate that this test strategy significantly en-hances system reliability, offering a valuable contribution to the development of more robust and maintainable FFC-NMR in-strumentation for scientific and industrial applications.