Amplitude-stabilized harmonic current source for mems microheaters with grounded load
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Дата
2025
Автори
Науковий керівник
Назва журналу
Номер ISSN
Назва тому
Видавець
КПІ ім. Ігоря Сікорського
Анотація
This paper presents the design, development, and experimental validation of a multi-stage AC current source with amplitude stabilization, specifically created for MEMS microheaters with grounded load in 3-omega gas sensing applications. The proposed system is based on a Raspberry Pi Pico microcontroller, an external R-2R ladder digital-to-analog converter, cascaded inverting amplifier stages, and an improved Howland current pump that ensures precise stabilization of the excitation current amplitude. Such an approach enables generation of a spectrally clean sinusoidal signal in the 20 Hz–20 kHz frequency range, with adjustable current amplitude up to 5 mA, zero-level offset control, and stable operation across heater-resistor systems with impedances from 50 Ω to 3 kΩ. Compared with conventional voltage-driven circuits, current-driven excitation in the 3-omega method ensures higher reproducibility, improved calibration consistency, and more accurate interpretation of thermal responses. The developed device successfully addresses challenges associated with grounded heater configurations and reduces dependence on bulky laboratory-grade instruments, offering a compact and low-cost solution suitable for both fixed-frequency and broadband thermal characterization of gases. Experimental results demonstrate that the source maintains frequency stability above 99.9 % and total harmonic distortion below 1 %, while deviations in current amplitude across the supported load range remain within acceptable limits (<1%), ensuring reliable application in thermal property extraction. The significance of the work lies not only in the practical realization of a robust excitation source but also in its potential to support integration of MEMS thermal gas sensors into portable and embedded platforms. The modular design and firmware-controlled signal generation enable straightforward tuning and future improvements such as digital feedback, precision matched resistor networks, or single-supply architectures. Overall, the developed current source provides a valuable and adaptable tool for experimental gas analysis, representing a meaningful step toward miniaturized and accessible gas sensing systems.
Опис
Ключові слова
3-omega method, thermal gas sensing, MEMS microheater, AC current source, current stabilization, метод 3ї гармоніки, теплові сенсори газу, МЕМС мікронагрівач, джерело змінного струму, стабілізація струму
Бібліографічний опис
Hrebonkin, Ye. O. Amplitude-stabilized harmonic current source for mems microheaters with grounded load / Hrebonkin Ye. O. // Вісник КПІ. Серія Приладобудування : збірник наукових праць. – 2025. – Вип. 70(2). – С. 38-50. – Бібліогр.: 23 назв.