應用於心電訊號感測之低功率轉導電容式連續時間三角積分調變器

A Low-Power Gm-C Continuous Time Sigma Delta Modulator for Electrocardiogram Signal Sensor

薛志培(Chih-Pei Hsueh)

指導教授 ： 朱元三 ； 李順裕

國立中正大學/工學院/電機工程學系/碩士(2014年)

摘要

近年來，心血管疾病與腦血管疾病位居世界十大死因之首，為了有效的治療相關疾病，必須長期採用可攜式無線感測系統來監控人體生理訊號，如心電圖、腦電圖等，而為了讓使用者長時間使用且隨身攜帶，感測系統必須達到低功率消耗與相對應的規格要求。
本論文針對生醫規範之感測系統提出一套應用於無線傳輸感測系統的類比前端電路，內部電路採用新穎三角積分調變器，包括截波調變器、低通三角積分調變器與截波穩定數位濾波器，其中截波調變器不僅可避免低頻雜訊且可透過提高輸入訊號頻率來增加低通三角積分調變器內積分器的線性度；而低通三角積分調變器採用連續時間Gm-C架構來實現，並且建立Gm-C架構的設計流程；之後再透過截波穩定數位濾波器濾除頻寬以外之雜訊與解調訊號回基頻。此電路採用TSMC 0.18um 1P6M CMOS製程來實現，其生理訊號頻寬為200 Hz，在取樣頻率為256 kHz及供應電壓1V之情況下，量測結果顯示SNR與SNDR分別為52.03 dB與47.49 dB，動態範圍為53.97 dB，總功率消耗為5.223 uW。

關鍵字

弱反轉區 ； 生醫訊號 ； Gm-C積分器 ； 連續時間三角積分調變器 ； 類比前端 ； 低功率

並列摘要

The top of the 10 leading causes of death in the world are Ischemic heart disease as well as Stroke and other cerebrovascular disease in recent years. In order to effectively treat related diseased, a portable wireless sensing system is required to monitor human biomedical signals, such as EEG or ECG. The sensing system should be low power and has the corresponding specifications to allow users for long-term use and carry conveniently.
According to the required specifications of a wireless bio-signal acquisition system, this thesis proposes a novel sigma delta modulator structure, including a chopper, a low-pass sigma delta modulator and a digital filter with a chopper. The chopper can not only avoid the injection of low-frequency noise caused by devices but also increase the linearity of integrator by increasing input signal frequency in LPSDM. Moreover, the LPSDM is implemented in continuous time Gm-C architecture and the systematic design flow is introduced. The digital filter with a chopper is adopted to filter the quantization noise and to demodulate the input signal. The circuit is implemented in TSMC 0.18μm 1P6M CMOS process. The desired signal bandwidth is 200 Hz. The measured results with sampling frequency of 256 kHz reveal the SNR and SNDR are 52.03 dB and 47.49 dB, respectively. The dynamic range is 53.97 dB. The total power consumption is 5.223 uW under supply voltage of 1V.

並列關鍵字

Low power consumption ； Analog front-end ； Weak inversion ； Biomedical signal ； Gm-C integrator ； Continuous time sigma delta modulator

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