| 摘要: | 植入式醫療裝置(IMD)是指透過手術植入人體的醫療裝置，早期的植入式醫療裝置作為獨立裝置運行，需要透過有線電極或是短程通訊設備溝通，對病患日常生活有著相當程度的影響。如今有多種通訊協定通過小型移動通訊裝置接收生醫訊號，並與終端機溝通將資料上傳至雲端，方便醫生隨時進行診斷與維護實現遠距醫療。本研究基於植入式醫療裝置應用，提出開發多樣化植入式醫療裝置的無線電力與雙向資料傳輸系統。本研究將整個無線傳輸系統分成發射系統與接收系統，並且將關鍵電路以晶片電路實現，製程採用TSMC 0.18 μm CMOS Technology實現。
在發射系統，本研究提出11-Bits SAR ADC晶片的電源電壓1.2V，輸入電壓範圍為300mV~900mV，採樣率10kS/s。在解析度與採樣速率取得平衡，且在DNL與INL上優異的表現均低於0.5 LSB，確保ADC不會出現漏碼（missing codes），選擇非同步的架構減少時脈產生的雜訊（jitter），可透過SFDR觀察對時脈抖動的表現，78.9dBc的數值表明確實在jitter的處理上表現優異。在植入式醫療裝置的考量上，本研究ADC功耗僅為932nW對IMD幾乎可忽略不計，產生熱量遠低於組織代謝熱，∆T<0.001℃。其數據表明長時間植入不會對周圍組織產生熱損傷，加上實際ENOB有9.2 bits十分適合IMD應用。
在接收系統，本研究提出升壓比較整流器電路，使用電感耦合無線電力傳輸位晶片供電，輸入訊號為振福3.3頻率2 MHz正弦波。可得到VCE在R_L=8kΩ時達89.02%，PCE在R_L=500Ω時有84.73%，最大輸出電流為5 mA，整流晶片功率消耗為12.35 mW。採用ALL-NMOS功率電晶體的整流架構避免出現寄生P-N-P-N結構，遏止因P-N-P-N結構發生latch-up，並設計保護電路以避免電晶體節點因高壓損壞。本研究提出整流器晶片電路實現，應用於2 MHz的操作頻率兼具電感耦合線圈大小與人體吸收率SAR低。5 mA的最大輸出電流適合多數植入式應用，89.02%的VCE和2.94V的穩定輸出電壓，滿足大多數供電需求。84.73%的PCE局部溫升僅0.22-0.45℃，符合ISO與IEC所規範的2℃。各項指標均顯示此設計是符合IMD應用。
;Implantable medical devices (IMDs) are devices surgically implanted into the human body. Early IMDs functioned as stand-alone units, relying on wired electrodes or short-range communication equipment, which significantly affected patients′ daily lives. Today, various communication protocols enable small mobile devices to receive biomedical signals and communicate with terminals to upload data to the cloud, facilitating remote diagnosis and maintenance by healthcare professionals. This research, based on the application of IMDs, proposes the development of a wireless power and bidirectional data transfer system for multiple implantable medical devices. This research divides the wireless transfer system into a transmitter system and a receiver system. TSMC′s 0.18 μm CMOS technology is employed to realize the key circuits: ADC and rectifier.
This study proposes a 10kS/s, 11-bit SAR ADC designed for transmitter systems. Powered by a 1.2 V supply, the device handles input signals ranging from 300 mV to 900 mV. A balance is achieved between medium resolution and medium sampling rate, with excellent performance in both DNL and INL, each below 0.5 LSB, ensuring no missing codes. An asynchronous architecture is employed to reduce clock jitter, and the effectiveness in handling clock jitter is demonstrated by an SFDR value of 78.9dBc, indicating excellent jitter tolerance. Considering implantable medical devices, the ADC’s power consumption is only 932 nW, which is negligible for IMDs, and the heat generated is far lower than tissue metabolic heat (∆T<0.001℃). These data indicate that long-term implantation will not cause thermal damage to surrounding tissues, and the actual ENOB of 9.2 bits is well suited for IMD applications.
This study proposes a boost-comparator rectifier circuit for the receiver system, powered by an inductive coupling wireless power transfer. An inductive coupling wireless power transfer system generates the input signal, which is characterized as a 2 MHz sine wave with a 3.3 V amplitude. The VCE reaches 89.02% at a load resistance (R_L) of 8 kΩ, while the PCE attains 84.73% at R_L=500Ω. The maximum output current is 5 mA, and the rectifier chip′s power consumption is 12.35 mW. Rectifier architecture with all-NMOS power transistors is employed to eliminate parasitic P-N-P-N structures, thereby preventing latch-up. This study proposes a self-bootstrapping architecture to improve the insufficient charging efficiency of NMOS devices and incorporates protection circuits to prevent transistor node breakdown from high voltage. The proposed rectifier circuit operates at 2 MHz, balancing the size of the inductive coupling coil and the specific absorption rate (SAR) in the human body. The maximum output current of 5 mA is suitable for most implantable applications. The VCE of 89.02% and a stable output voltage of 2.94 V meet typical power supply requirements. The PCE results in a local temperature rise of only 0.22–0.45°C, well within the 2°C limit specified by ISO and IEC standards. All performance indicators demonstrate that this design complies with IMD application requirements. |
