本論文內容實現了兩個應用於生醫濃度感測之恆電位儀電路，用來感測待測溶液的物質濃度。由於不同待測溶液濃度造成不同的等效電阻，所以固定電壓量測法可以用來偵測不同待測溶液濃度所造成不同的還原反應電流。
在第一個架構中，採用伏安式恆電位儀架構，其中包括一個積分器、一個電壓轉時間轉換器以及一個14位元數位計數器，其架構原理是將電流訊號轉換成時間訊號，再利用計數器轉換成數位資訊作輸出。透過數位資訊的大小，可以推估出溶液濃度。模擬結果顯示，整個電路的總消耗功率為3.03 mW，而還原反應電流可量測範圍為1 nA ~ 15 μA。實驗量測結果，整個電路的總消耗功率為4.32 mW，而還原反應電流可量測範圍為50 nA ~ 15 μA。
在第二個架構中，其中包括一個電流轉換器、一個電流轉時間轉換器以及一個14位元數位計數器，其架構原理是將電流訊號轉換成時間訊號，再利用計數器轉換成數位資訊作輸出。此電路，整個電路的總消耗功率為1.84 mW，而還原反應電流可量測範圍為1 nA ~ 3 μA。
本論文使用0.35 μm二層多晶矽金屬之互補式金氧半製程。

This thesis proposes two potentiostatic circuits for bio-medical application. These two potentiostatic circuits could be used to sense the concentration of the target molecules in the solution under measurement. Since the equivalent resistance of the solution under measurement is strongly related with the solution concentration, the fixed voltage current measuring method is adopted to detect the different current resulting in different concentration of the solution under measurement.
In the first prototype, a voltammetric potentiostat, which consists of an integrator and a voltage-to-time converter, is presented to transform current signal to time signal. Then, a counter is utilized to transform the time duration into a digital data. Finally, the solution concentration can be derived from the relationship between the digital data and the current depended on the solution concentration. From the simulation, the range of the sensing current is from 1 nA to 15 μA. This work is simulated in a 0.35 μm 2P4M 5-V CMOS process. The total power consumption is 3.03 mW excluding the digital counter. In the measurement result, the total power consumption is 4.32 mW, and the range of sensing current is from 50 nA to 15 μA.
In the second prototype, which consists of a current converter, a current-to-time converter and a counter, is utilized to transform the analogous current into digital expression. In this work, the range of sensing current is from 1 nA to 3 μA. The power consumption is 1.84 mW excluding the digital counter. This work is simulated in a 0.35 μm 2P4 M 5-V CMOS process.

[1] W. Y. Chung, A. C. Paglinawan, Y. H. Wang, and T. T. Kuo “A 600 μW readout circuit with potentiostat for amperometric chemical sensors and glucose meter applications,” in Proc. EDSSC, Dec. 2007, pp. 1087–1090.
[2] R. D. Beach, R. W. Conlan, M. C. Godwin, and F. Moussy, “Towards a miniature implantable in vivo telemetry monitoring system dynamically configurable as a potentiostat or galvanostat for two- and three-electrode biosensors,” IEEE Trans Instrum. Meas., vol. 54, pp. 61–72, Feb. 2005.
[3] L. Huaqing, L. Xianbo, L. Chunxiu, J. Liying, C. Dafu, C. Xinxia, and Y. Qingde, “Multi-channel electrochemical detection system based on LabVIEW,” in Proc. IEEE Inform. Acquisition, June 2004, pp. 224–227.
[4] J. Zhang, N. Trombly, and A. Mason, “A low noise readout circuit for integrated electrochemical biosensor arrays,” IEEE Trans. Instrum. Meas., Vol. 47, pp. 1191–1196, Oct. 1998.
[5] S. C. Cheng, W. Y. Chung, C. C. Chuang, and F. R. G. Cruz, “A wide current range readout circuit with potentiostat for amperometric chemical sensors,” in Proc. Int. conf. Biomed. Eng., May. 2008, pp. 1406–1410.
[6] R. G.. Kakerow, H. Kappert, E. Spiegel, and Y. Manoli, “Low-power single-chip CMOS potentiostat,” in Proc. IEEE Int. Conf. on Solid-State Sensors and Actuators, June 1995, pp. 142-145.
[7] R. Greef, “Instruments for use in electrode process research,” J. Phys. E, Sci. Instrum., vol. 11, pp. 1–12, Jan. 1978.
[8] M. M. Ahmadi and G. A. Jullien, “Current-mirror based potentiostats for three-electrode amperometric electrochemical sensors,” IEEE Trans. Circuits Syst. I, vol. 56, pp. 1339-1348, July 2009.
[9] R. F. B. Turner, D. J. Harrison, and H. P. Baltes, “A CMOS potentiostat for amperometric chemical sensors,” IEEE J. Solid-State Circuits, vol. 22, pp. 473-478, June 1987.
[10] J. C. Fidler, W. R. Penrose, and J. P. Bobis, “A potentiostat based on a voltage-controlled current source for use with amperometric gas sensors,” IEEE Trans Instrum. Meas., vol. 41, pp. 308-310, Apr. 1992.
[11] R. J. Reay, S. P. Kounaves, and G. T. A. Kovacs, “An integrated CMOS potentiostat for miniaturized electroanalytical instrumentation,” in IEEE ISSCC Dig. Tech. Papers, Feb. 1994, pp. 162-163.
[12] M. Breten, T. Lehmann, and E. Braun, “Integrating data converters for picoampere currents from electrochemical transducers,” in Proc. IEEE Int. Symp. Circuits Syst., May 2000, pp. 709-712.
[13] A. Bandyopadhyay, G. Mulliken, G. Cauwenberghs, and N. Thakor, “VLSI potentiostat array for distributed electrochemical neural recording,” in Proc. IEEE Int. Symp. Circuits Syst., May 2002, pp. 740-743.
[14] A. Frey, M. Jenkner, M. Schienle, C. Paulus, B. Holzapfl, P. Schindler-Bauer, F. Hofmann, D. Kuhlmeier, J. Krause, J. Albers, W. Gumbrecht, D. Schmitt-Landsiedel, and R. Thewes, “Design of an integrated potentiostat circuit for CMOS bio sensor chips,” in Proc. IEEE Int. Symp. Circuits Syst., May 2003, pp. 9-12.
[15] S. M. Martin, F. H. Gebara, T. D. Strong, and R. B. Brown, “A low-voltage, chemical sensor interface for systems-on-chip: the fully-differential potentiostat,” in Proc. IEEE Int. Symp. Circuits Syst., May 2004, pp. 892-895.
[16] H. S. Narula and J. G. Harris, “VLSI potentiostat for amperometric measurements for electrolytic reactions,” in Proc. IEEE Int. Symp. Circuits Syst., May 2004, pp. 457-460.
[17] W. Y. Liao, Y. G. Lee, C. Y. Huang, H. Y. Lin, Y. C. Weng, and T. C. Chou, “Telemetric electrochemical sensor,” Biosens. Bioelectron., Oct. 2004, pp. 482-490.
[18] A. Hassibi, and T. H. Lee, “A programmable electrochemical biosensor array in 0.18m standard CMOS,” in IEEE ISSCC Dig. Tech. Papers., Feb. 2005, pp. 564-565 & 617.
[19] A. Gore, S. Chakrabartty, S. Pal, and E. C. Alocilja, “A multichannel femtoampere-sensitivity potentiostat array for biosensing applications,” IEEE Trans. Circuits Syst. I, vol. 53, pp. 2357-2363, Nov. 2006.
[20] M. Stanacevic, K. Murari, G. Cauwenberghs, and N. Thakor, “16-channel wide-range VLSI potentiostat array,” in Proc. IEEE BioCAS, Dec. 2004, pp. SI/7/INV/17- SI/7/INV/20.
[21] K. Murari, M. Stanacevic, G. Cauwenberghs, and N. Thakor, “Wide-range, picoampere-sensitivity multichannel VLSI potentiostat for neurotransmitter sensing,” in Proc. IEMBS, Dec. 2004, pp. 4063-4066.
[22] K. Murari, M. Stanacevic, G. Cauwenberghs, and N. Thakor, “VLSI potentiostat array with oversampling gain modulation for wide-range neurotransmitter sensing,” IEEE Trans. Biomed. Circuits Syst., vol. 1, pp. 63-72, Mar. 2007.
[23] R. J. van de Plassche, “A sigma-delta modulator as an A/D converter,” IEEE Trans. Circuits Syst. I, vol. 25, pp. 510-514, July 1978.