本論文提出了一個可應用於寬廣動態範圍電流量測之時間轉換型恆電位儀。文中提出了一種可藉由偵測時間輸出判斷目前量測電流範圍並自動切換到適當倍率電流鏡之電路架構，此架構可用來實現寬廣動態範圍電流量測且具備低功率消耗之特性，適合應用於設計各種不同規格之恆電位儀。此外，文中亦提供了一個有效率的設計方法配合所提出之架構去設計恆電位儀，在設計之初就能對恆電位儀晶片之各參數做取捨，如：動態電流範圍、取樣頻率、解析度、功率消耗、晶片面積等等。
此設計以聯華電子公司0.18µm一層多晶矽六層金屬導線CMOS製程來實現，電路效能透過佈局模擬表現出126 dB (1 nA至2 mA)之動態電流範圍，最小量測電流範圍之電流解析度小於10 pA。電路之取樣頻率為1 kHz，最小功率消耗僅12 µW。電路效能足以符合各種不同生物感測器之需求。第一版晶片之量測結果與布局模擬結果相符，驗證了本論文所提設計方法與電路之可行性。

A Time based potentiostat for wide dynamic range current measurement is presented in this thesis. We propose a circuit architecture which is well suited for designing a wide dynamic range current-to-time converter, and it is able to be used in potentiostat design for different requirements. Therefore, we provide an efficient way to make trade-offs among all the parameters, such as dynamic range, sampling frequency, resolution, power dissipation, chip area and so on.
The proposed design is implemented in UMC 0.18-μm 1P6M CMOS technology. Circuit performance is characterized through post-layout simulation, showing a wide dynamic input current range of 126 dB (1 nA–2 mA), and the resolution at the minimum current range is smaller than 10 pA. The sampling frequency of the circuit is 1 kHz, and the minimum power dissipation is only 12 μW. Circuit performances are able to meet the requirements of different kinds of biosensors. The measurement results of the first version of the chip match with the simulation results. It demonstrates that the feasibility of the proposed method and circuit is good.

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