應用於植入式系統之生醫收發機

Abstract

近年來，老年人口快速的增加，是全球重要的課題。並且隨著無線通訊以及網路的迅速發展，病人就可留在家中接受家人的照顧而不必待在無趣醫院裡面冒著受到其他傳染病危害的風險。因此居家照護因應而生，利用無線通訊達到無線監測和記錄來獲得病人及時的生理參數。不僅對病人和家屬可減少不必要的痛苦和金濟開銷，也減輕醫療人員的工作負擔。藉由長期的監控也會及早發現一些在特定時間才會發生的病徵，例如心律不整等。生理無線監控設備具有以下幾個特點，短距離傳輸、低功耗、低成本。為了達到以上的目標，本篇論文提出低功率取樣接收機和去除低雜訊法大器的超級再生是收發機。本論文的收發機操作在台積電 0.18 微米製程，為了降低功率消耗，操作再低電壓 1 伏特，其功率消耗為 226.3μW 以及 386μW。 首先介紹如何用低功率取樣接收機來解調OOK訊號。藉由比載頻低很多的取樣頻率做為系統的操作頻率。除去較為耗電的電路，例如振盪器和混頻器。利用以上的方式減少接收機的功耗。本系統先利用一個低雜訊放大器並五級的雙端放大器放大訊號，利用採樣保持電路將訊號從擷取出來。後端的電路將訊號放大並用比較器比較電壓大小以解調OOK訊號。 接著介紹除去低雜訊放大器的超級再生OOK收發機。利用匹配電路讓訊號得以進入數位控制震盪器，當訊號出現時會讓數位控制震盪器提早起振，後端的電路藉由區分起振時間的快慢就可解調出OOK訊號。 最後我們將超級再生OOK收發機整合進心電量測晶片ECG中，此電路在非常低功耗的狀態下可傳輸訊號超過1公尺並可利用OOK或FSK模式進行傳輸。藉由其低功耗的特性，讓整體系統能用於長期身理監控。

Nowadays, the aging population increasing rapidly has become the significant issue around the world. With the fast progress of wireless communication and internet, the patients and stay home and their family can take care of them. They do not need to stay at boring hospital and face the risk of getting infection with bacteria. The homecare technology achieves health monitoring and remote medical diagnosis to acquire the timely physiological parameter of patients by wireless communication. The homecare technology not only reduce unnecessary pain and financial cost and also dampen the work burden of medical staff. By the long term health monitoring we can also discover symptom of disease which happens in specific time, such as Cardiac dysrhythmia. The characteristic of wireless health monitoring devices are short distance communication, low power consumption, and low cost. To achieve above requirement. The thesis proposes low power subsampling receiver and super-regenerative receiver without Low Noise Amplifier (LNA). The receivers are both implemented in producing TSMC 0.18um COMS process. To reduce the consuming power, the supply voltage is 1 volt, and the consuming power is 226.3μW and 386μW, respectively. Firstly, we introduce the subsampling architecture. By using sampling frequency which is much lower than carrier frequency as operating frequency and removing the power hungry circuit, such as DCO and mixer, we decline the power consumption of receiver. The LNA and five stages differential amplifier are used to amplify the signal. And the sample and hold circuit sample the voltage from OOK signal. By comparator we separate signal “1” from “0”. Secondly, we introduce the super-regenerative receiver without LNA. By careful design, the matching network can send signal in band to DCO. And the DCO will oscillate earlier when signal is “1” and vice versa. The backside circuit will define signal “1” or “0” by oscillation time of DCO. Finally, we integrate the super-regenerative receiver into ECG system. The receiver can communicate over 1 meter in OOK or FSK mode. The low power consumption of receiver make whole system achieve long-term health monitor.