靴帶式之寬動態範圍4T架構CMOS生醫影像感測器

Abstract

近幾年CMOS影像感測器發展應市場需求有著蓬勃發展，不論是在3C消費型產品、車用電子產品與生醫電子產品，如手機照相機、視訊攝影機、Wii遊戲機、倒車偵測器、膠囊內視鏡、可穿戴環型感測器以及生醫待測物偵測。CMOS影像感測器較CCD感測器有著易於作系統晶片整合，且擁有低電壓、低面積以及低功耗之優勢。 本論文設計一高動態範圍之生醫CMOS影像感測器用以偵測生醫待測物，生醫影像感測器之架構分為類比前端影像感測部分與數位控制訊號部分，首先類比部分採用4T架構之主動像素影像感測器(Active Pixel Sensor，APS)、靴帶式(Bootstrap)電路與相關雙取樣電路(Correlated Double Sample，CDS)，數位部份用以產生不同週期訊號用來控制內部行列陣列，採用全客戶式CMOS電路來實現多工器(Multiplexer)、解多工器(Deultiplexer)以及計數器(Counter)來實現。 本晶片採用TSMC 0.18μm CMOS 1P6M混合訊號製程技術，整體面積為2.57×2.7 ，生醫影像感測器陣列大小為32×32共1024細胞感測器，晶片之供應電壓為1.5V整體功耗為5.97mW，光二極體採用n+井/P基座，填滿因素達56.75%，動態範圍高達90.3dB。

CMOS image sensors have drawn much high-tech product market’s attention in recent year. The products apply to 3C consumer type, automotive application and biomedical CMOS image sensor. Such products are cell-phone cameras, video cameras, Wii game boxes, park assist systems, smart pills, wearable ring sensors and biomedical subject detection sensors. In comparison with charge coupled devices (CCD), CMOS image sensor demonstrates great circuit integration capability, low voltage, low area and low power consumption design. In this thesis, the biomedical CMOS image sensor (BIOCIS) with high dynamic range are proposed and designed into a chip that detects subject. This sensor structure comprises the analog part used to sense front image signals and the digital part exploited to control some digital signals. To illustrate, the analog part design is composed of 4-T Active Pixel Sensor (APS), bootstrap circuit, Correlated Double Sample (CDS), while the digital part design is constructed by full custom to realize multiplexers, deultiplexers and counters. This BIOCIS chip is fabricated TSMC 0.18μm COMS Mixed-Signal RF General purpose MiM Al 1P6M 1.8&3.3V process and occupies the area of 2.57×2.7 . BIOCIS has 1024 pixel cell sensors and pixel array 32×32. The total power consumption is about 5.97mW under 1.5V supply voltage. The photodiode structure use n+/p-substrate type, fill factor of 56.75% and high dynamic range of 90.3dB.