標題: | Improved Charge Pump Design and Ex Vivo Experimental Validation of CMOS 256-Pixel Photovoltaic-Powered Subretinal Prosthetic Chip |
作者: | Kuo, Po-Han Wong, Oi-Ying Tzeng, Chi-Kuan Wu, Pu-Wei Chiao, Chuan-Chin Chen, Po-Hung Chen, Po-Chun Tsai, Yueh-Chun Chu, Fang-Liang Ohta, Jun Tokuda, Takashi Noda, Toshihiko Wu, Chung-Yu 材料科學與工程學系 電子工程學系及電子研究所 Department of Materials Science and Engineering Department of Electronics Engineering and Institute of Electronics |
關鍵字: | Electrodes;Retina;Charge pumps;Implants;Optical imaging;Optical pumping;Optical sensors;Divisional power supply scheme;photovolltaic cell;multi-electrode array;charge pump;biocompatible package |
公開日期: | 1-五月-2020 |
摘要: | An improved design of CMOS 256-pixel photovoltaic-powered implantable chip for subretinal prostheses is presented. In the proposed subretinal chip, a high-efficiency fully-integrated 4x charge pump is designed and integrated with on-chip photovoltaic (PV) cells and a 256-pixel array with active pixel sensors (APS) for image light sensing, biphasic constant current stimulators, and electrodes. Thus the PV voltage generated by infrared (IR) light can be boosted to above 1V so that the charge injection is increased. The proposed chip adopts the 32-phase divisional power supply scheme (DPSS) to reduce the required supply current and thus the required area of the PV cells. The proposed chip is designed and fabricated in 180-nm CMOS image sensor (CIS) technology and post-processed with biocompatible IrOx electrodes and silicone packaging. From the electrical measurement results, the measured stimulation frequency is 28.3 Hz under the equivalent electrode impedance load. The measured maximum output stimulation current is 7.1 mu A and the amount of injected charges per pixel is 7.36 nC under image light intensity of 3200 lux and IR light intensity of 100 mW/cm(2). The function of the proposed chip has been further validated successfully with the ex vivo experimental results by recording the electrophysiological responses of retinal ganglion cells (RGCs) of retinas from retinal degeneration (rd1) mice with a multi-electrode array (MEA). The measured average threshold injected charge is about 3.97 nC which is consistent with that obtained from the patch clamp recording on retinas from wild type (C57BL/6) mice with a single electrode pair. |
URI: | http://dx.doi.org/10.1109/TBME.2019.2938807 http://hdl.handle.net/11536/154310 |
ISSN: | 0018-9294 |
DOI: | 10.1109/TBME.2019.2938807 |
期刊: | IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING |
Volume: | 67 |
Issue: | 5 |
起始頁: | 1490 |
結束頁: | 1504 |
顯示於類別: | 期刊論文 |