應用於視網膜療程之植入式人工視網膜與其電源控制電路

Abstract

本篇論文中描述一個應用於下視網膜療程中的人工矽視網膜晶片設計。包含光電池架構的設計、晶片時脈產生器的設計、基本像素的設計與電能控制系統的設計。在光電池供電系統中，我們提出新的光電池架構並將電路系統與光電池同時整合在CMOS積體電路晶片上的設計也經由許多相關的測試元件與設計改良驗證其使用特性。我們並且初步設計並實作由感光二極體陣列構成之視網膜晶片的體外生物實驗，成功的驗證視網膜晶片刺激視網膜細胞的生物反應。而晶片時脈系統經過設計、模擬、量測後驗證為一超低功率時脈產生器，此振盪器可在3.6mW/cm2的光照強度下產生1.632KHz的震盪其電路消耗功率僅為5.2nW。此植入式人工視網膜晶片使用了由生物特性啟發而得的電能控制系統，所以在下視網膜療程中的電能使用效益上有所改善。在應用此分區供電的架構下，此晶片可以產生約三倍的有效輸出電流已提供視網膜細胞所需要的電性刺激。此晶片在3.6mW/cm2的光照強度下可以得到約略844nA的電流輸出、在5.06mW/cm2的光照強度下可以得到約略1.72μA的電流輸出。在台灣積體電路製造股份有限公司與國家晶片系統中心的幫助下，此視網膜晶片將以0.18微米製程實現。基於上述特性，此光電池架構、視網膜晶片與電源控制系統對下視網膜療程中的人工矽視網膜晶片設計上有相當程度的貢獻。

In this thesis, a retinal chip has been designed, analyzed, and fabricated to improve the power efficiency of the sub-retinal prostheses. The preliminary in vitro experiment of the silicon retina chip which composed of micro photodiode array has also been designed and verified. The silicon retina with MPA can successfully trigger the retina cell and the electrical-response is similar to the light-response in retina cell. The feasibility of on-chip solar cell supply system which integrated with circuit system in CMOS technology has been verified in the work. An ultra-low power clock generator is also designed and verified in this work. This clock generator can generate a clock signal with 1.632KHz under 3.6mW/cm2 incident light intensity with only 5.2nW power consumption. A three times output stimulating current is achieved by taking advantage of the bio-inspired divisional power supply architecture. The stimulating output current is approximately 844nA under the illumination of 3.6mW/cm2 light intensity and 1.72μA under the illumination of 5.06mW/cm2 light intensity. The retinal chip fabricated with a standard 0.18μm tsmc CMOS process demonstrate good mimic of electrical behavior of human retina with low-power consumption. Because of its characteristic, the proposed power management system could be considered as one of the highly integrated solutions for the sub-retinal implant chips.