1225-Channel Neuromorphic Retinal-Prosthesis SoC With Localized Temperature-Regulation

Abstract

A 1225-Channel Neuromorphic Retinal Prosthesis (RP) SoC is presented. Existing RP SoCs directly convert light intensity to electrical stimulus, which limit the adoption of delicate stimulus patterns to increase visual acuity. Moreover, a conventional centralized image processor leads to the local hot spot that poses a risk to the nearby retinal cells. To solve these issues, the proposed SoC adopts a distributed Neuromorphic Image Processor (NMIP) located within each pixel that extracts the outline of the incoming image, which reduces current dispersion and stimulus power compared with light-intensity proportional stimulus pattern. A spike-based asynchronous digital operation results in the power consumption of 56.3 nW/Ch without local temperature hot spot. At every 5×5 pixels, the localized (49-point) temperatureregulation circuit limits the temperature increase of neighboring retinal cells to less than 1°C, and the overall power consumption of the SoC to be less than that of the human eye. The 1225-channel SoC fabricated in 0.18 µm 1P6M CMOS occupies 15mm 2 while consuming 2.7 mW, and is successfully verified with image reconstruction demonstration.

Ambient Light Rejection Integrated Circuit for Autonomous Adaptation on a Sub-Retinal Prosthetic System

“…The prior literature presented in [ 8 , 9 , 21 , 33 ] only has stimulation pixels. Although Park et al [ 7 ] developed an edge stimulation method to increase contrast sensitivity, it cannot compensate for pixel saturation caused by the ambient light. Rothermel et al [ 34 , 35 ] proposed an ambient light rejection technique that operates with 3025 stimulation pixels.…”

“…Retinal implants have great promise in restoring vision for the blind, who suffer from retinal diseases such as retinitis pigmentosa and age-related macular degeneration [ 1 , 2 , 3 , 4 ]. The fundamental idea for retinal prosthetics is to electrically stimulate impaired retina cells using a microelectrode array and its driving circuitry [ 5 , 6 , 7 , 8 , 9 ]. This retinal prosthesis can be classified into epi-retinal [ 5 , 6 ] and sub-retinal implants [ 7 , 8 , 9 ], based on the anatomical location.…”

“…The fundamental idea for retinal prosthetics is to electrically stimulate impaired retina cells using a microelectrode array and its driving circuitry [ 5 , 6 , 7 , 8 , 9 ]. This retinal prosthesis can be classified into epi-retinal [ 5 , 6 ] and sub-retinal implants [ 7 , 8 , 9 ], based on the anatomical location. While the epi-retinal implant is placed onto an inner retinal layer, known as the ganglion cells, the subretinal implant is located in the outer retina, called photoreceptor cells.…”

A 36-Channel Auto-Calibrated Front-End ASIC for a pMUT-Based Miniaturized 3-D Ultrasound System

“…Therefore, a 36-channel system should consume less than 13.9 mW/channel. Especially, localized hot spots should be avoided to prevent cell damages [6], [7]. Previous works that integrate a power-consuming transmitter (TX) and centralized analog-to-digital converter (ADC) [8] can cause localized hotspots; therefore, it is more suitable to have each transceiver (TRX) integrated in-pixel to minimize such hot spots.…”

A Fully Energy-Autonomous Temperature-to-Time Converter Powered by a Triboelectric Energy Harvester for Biomedical Applications

“…overheating becomes detrimental to not only device performance but more importantly for tissues that suffer from thermal damage when exposed to high temperatures above 43 • C [1]. Therefore, implanted systems, such as [2] and [3], require temperature data to ensure patients' safety. Conversely, detection of temperatures below meaningful range detectable on body (<36 • C) could signal a potential detachment in need of prompt discovery and adjustment.…”