應用於下視網膜植入具光伏特電池及分區供電之180奈米互補式金氧半256像素感測及雙向刺激晶片設計

Abstract

本篇論文提出及分析應用於下視網膜互補式金氧半太陽能電池256像素刺激晶片移植系統，晶片架構基於分區供電方式(DPSS)和主動式像素元件(APS)改良輸出刺激電流之效率。實驗之晶片八區分區供電為16x16的光二極體陣列以及控制訊號產生電路。而晶片採用台積電0.18um互補式金氧半CIS製程工藝。最終的晶片尺寸為3mm x 3mm，DPSS11在5mW/cm2 之訊號光以及80mW/cm2 之紅外線背景光照射下量測，負載為10-kΩ時控制訊號頻率為47.68赫茲，輸出的雙向刺激電流有19.9uA;負載為生物模型時控制訊號頻率為45.45赫茲，輸出的雙向刺激電流有19.52uA，累積電荷量為1.1nC。DPSS12在0.4 mW/cm2 之訊號光以及80mW/cm2 之紅外線背景光照射下量測，負載為10-kΩ時控制訊號頻率為30.2赫茲，輸出的雙向刺激電流有19.95uA;負載為生物模型時控制訊號頻率為30.2赫茲，輸出的雙向刺激電流有19.84uA，累積庫倫量為1.64nC，此量測結果驗證了晶片可以正常操作。

A photovoltaic-cell-powered CMOS 256-pixel implantable chip is proposed for subretinal prostheses. In the proposed chip, the divisional power supply scheme (DPSS) and the active pixel sensor (APS) are adopted to improve the efficiency of output stimulation currents and the image sensitivity. The proposed chip consists of a 16x16 photodiode array with 8 DPSS divisions, control signal generator circuits, and photovoltaic cells. It is designed and fabricated in 180-nm CMOS image sensor (CIS) technology. The chip size is 3mm x 3mm. The DPSS11 measured frequency of eight-phase control signals is 47.68 Hz under signal light intensity of 5 mW/cm2 and background IR intensity of 80 mW/cm2. The measured output stimulation current is 19.9 μA under 10-kΩ load. Under the equivalent electrode impedance load, the measured frequency of eight-phase control signals is 45.45 Hz. The measured peak output stimulation current is 19.52 μA and the amount of injected charges per pixel is 1.1 nC. The DPSS12 measured frequency of eight-phase control signals is 30.2 Hz under signal light intensity of 0.4 mW/cm2 and background IR intensity of 80 mW/cm2. The measured output stimulation current is 19.95 μA under 10-kΩ load. Under the equivalent electrode impedance load, the measured frequency of eight-phase control signals is 30.2 Hz. The measured peak output stimulation current is 19.84 μA and the amount of injected charges per pixel is 1.64 nC. The measurement results have verified the correct function of the proposed subretinal implant chip.

DPSS11—CMOS CIS 256-pixel subretinal chip version I DPSS12-- CMOS CIS 256-pixel subretinal chip version II