應用於核酸適體生物感測器之電感式無線電力傳輸與電源管理電路設計

Abstract

近年來，核酸適體作為新型生物感測技術受到關注，能高度準確地結合特定目標分子，這些分子在與目標結合時會發生結構變化，從而實現對目標分子的高度準確性和敏感性檢測。結合互補金氧半導體感測器技術，為即時測試等提供新空間。本論文探索核酸適體與互補金氧半導體感測器及即時測試的結合，即核酸適體感測器，提供高效的醫學解決方案。 作者為此應用開發了全片上無線供電傳輸系統和電源管理單元。由於應用限制，該電路會在水中運作，導致系統性能（功率傳輸效率）降低。因此，作者提出了一個解決方案，利用光阻來屏蔽芯片上的電感(線圈)，以緩解問題。此生物感測系統採用180奈米互補式金氧半導體製程製作，片上整合了兩種尺寸的片上電感，其一尺寸為1.46 mm×1.46 mm，供電頻率設計在915MHz至1GHz之間，其為此系統之主要供電線圈，另一尺寸為0.5 mm×0.5 mm，供電頻率設計在1.2GHz至1.24GHz之間，其功能為驗證主要線圈之效能與模擬之差異。對於主線圈來說，傳輸至負載功率達至4 mW，此線圈於空氣環境下，可達到6.7%之功率傳輸效益，而水環境下僅可達到2.25%之功率傳輸效益，使用光阻屏蔽片上電感時，可回復至接近6.5%之功率傳輸效益。對於驗證用的線圈來說傳輸至負載功率達至0.1 mW，此線圈於空氣環境下，可達到0.68%之功率傳輸效益，而水環境下僅可達到0.63%之功率傳輸效益，使用光阻屏蔽片上電感時，僅有0.48%之功率傳輸效益。 此外，通訊單元的原型也與無線供電傳輸系統一起實現。在我們的應用中，透過調變晶片上共振器的10％，可以實現資料反向散射（上行鏈路），我們可以偵測到初級側訊號有2dB變化。 電源管理單元部分，包含了可以交流至直流轉換器(整流器)以及代差參考電路，整流器擁有至少40%的轉換效率，並且可轉換超過4mW的功率。帶差參考電路提供一個參考電位，並且為整個系統提供偏壓電流，透過量測，此參考電位以及偏壓電流所受溫度以及供電電壓之影響甚小，代表其具有穩定性。 最後，有一個額外的線圈來進行測試，其主要目的為驗證電磁模擬模型是否建立的準確 。線圈尺寸是0.2 mm×0.2 mm，其諧振/操作頻率分別為2GHz，使用高頻探針量測進行驗證。

In recent years, nucleic acid aptamers have garnered attention as a novel biotechnological sensing technology. They can accurately bind to specific target molecules, undergo conformational changes upon binding, enabling highly accurate and sensitive detection of target molecules. Combined with complementary metal-oxide-semiconductor (CMOS) sensor technology, new opportunities are provided for real-time testing. This thesis explores the integration of nucleic acid aptamers with CMOS sensors and real-time testing, offering innovative and efficient medical solutions, namely aptamer-based biosensing The author has developed a fully on-chip wireless power transfer system and power management unit for this application. However, due to application constraints, the circuit operates underwater, resulting in a decrease in system performance (power transfer efficiency). Therefore, the author proposes a solution to use photoresist to shield the on-chip inductor (coil) to mitigate the problem. This biosensing system is fabricated using a 180-nm complementary metal-oxide-semiconductor process, integrating two sizes of on-chip inductors. One size measures 1.46 mm × 1.46 mm, with a power frequency designed between 915MHz and 1GHz, serving as the primary coil for this system. The other size measures 0.5 mm × 0.5 mm, with a power frequency designed between 1.2GHz and 1.24GHz, functioning to verify the performance difference between the primary coil and simulation. For the primary coil, power delivered to the load reaches 4 mW, achieving a power transfer efficiency of 6.7% in an air environment, and only 2.25% in a water environment. With the use of photoresist to shield the on-chip inductor, the efficiency can be restored to nearly 6.5%. For the verification coil, power delivered to the load reaches 0.1 mW, achieving an efficiency of 0.68% in an air environment and only 0.63% in a water environment. When using photoresist to shield the on-chip inductor, the efficiency drops to 0.48%. in addition, a prototype of communication unit is also implement with the on chip coil. by modulate 10% of on chip resonator can achieve data backscatter(uplink), we can detect 2dB change of signal on the primary coil The power management unit includes an AC-to-DC converter (rectifier) and a bandgap reference. The rectifier achieves a minimum power conversion efficiency of 40% and can convert power exceeding 4mW. The bandgap reference provides a reference and bias current for the entire system. Through measurements, it demonstrates the reference voltage and bias current exhibit minimal sensitivity to temperature and supply voltage, indicating stability. Finally, an additional coil is used for testing, primarily to validate the accuracy of the electromagnetic simulation model. The coil measures 0.2 mm × 0.2 mm and operates at resonance frequencies of 2GHz. Validation is performed RF probes.