應用於生醫微型系統之壓電材料介面面度與分子濃度感測電路

Abstract

這篇論文的主題主要分為二個部分，第一部分實作了一個低輸入範圍的壓電材料能量擷取電路。為了降低輸入電壓範圍，我們使用了負電壓轉換電路跟蕭基二極體，並且加入了啟動升壓電路讓電路在開機時能升壓供給電能給數位控制器。此能量擷取電路提出了創新的自動偵測壓電材料在輸入零電流時的開關開啟時的脈波寬度偵測電路，使得壓電材料的輸入功率能夠提升3.6倍。此外，我們也提出一個可適性零電流偵測電路再直流轉直流轉換器裡面，去減少電感關閉時的功率損耗。整體電能處理範圍為0.6V~2V的輸入電壓轉換成1V的穩定輸出電壓。此介面電路使用TSMC 0.18um CMOS製程。 第二個部分是偵測血液中急性冠狀動脈分子濃度的介面電路，此電路運用了低頻轉阻放大器將分子感測元件因為不同分子濃度而產生的電流訊號轉換成電壓訊號，再將此電壓訊號轉換成數位訊號輸出，得到的數位訊號輸出值正比於生物分子濃度值。若此分子元件及介面電路能夠成功偵測其訊號，醫院在偵測疾病時就無需使用昂貴的量測儀器。此電路能涵蓋的濃度偵測範圍，當使用cTnI為分子濃度指標時，其可偵測濃度範圍在320fM~3.2nM，而使用NT-proBNP微分子濃度指標時，其可偵測濃度範圍在320fM~32nM。此介面電路使用TSMC 0.18um CMOS製程。

This thesis consists of two parts. The first part implements a low input voltage piezoelectric (PZT) energy harvesting interface circuit. To lower the input voltage range, the negative voltage converter (NVC) with Schottky diode is implemented. The startup boost converter is also implemented to supply the power of the digital controller. The adaptive pulse width detector (PWD) is proposed to find the optimal turn-on time of the switches when input ac current of PZT harvester is approaching to zero. In addition, the adaptive zero-crossing detector is proposed for a DC-DC converter to reduce the power loss while the inductor is switching. The whole circuit can convert an input voltage from 0.6V~2V to realize a stable output voltage 1V. The circuit is implemented in TSMC 0.18um CMOS process. The second part is talking an interface circuit with digital output for acute myocardial infraction diagnosis. The low frequency transimpedance amplifier is implemented to convert the current signal from sensor to voltage signal under different bio-molecular concentration. Then, the voltage signal is converted to digital code which is proportional to different concentration. The sensor with its interface circuit can distinguish different bio-molecular concentration successfully; the expensive equipments are not needed in hospitals. When cTnI is used for bio-molecular target, the interface circuit can cover its concentration from 320fM~3.2nM. NT-proBNP is used for bio-molecular target, the interface circuit can cover its concentration from 320fM~32nM. The circuit is implemented in TSMC 0.18um CMOS process.