Integrated circuit design Controllers 4 Field programmable gate arrays (FPGA) 4 Controlled drug delivery 3 Cost effectiveness 3 Digital controller designs 3 Digital controllers 3 Field programmables 3 Field-programmable gated array 3 Hexagonal stimulation 3 Implant devices 3 Implants (surgical) 3 Micro/nano 3 Ophthalmology 3 Retinal implant technology 3 Subretinal implants 3 Timing circuits 3 Wireless telemetry systems 3 digital controller 3 field-programmable gated arrays 3 hexagonal stimulation 3 wireless telemetry system 3 Analog to digital conversion 2 Analog to digital converters 2 CMOS integrated circuits 2 Design-process 2 3-electrode sensing system 1 Analog modules 1 CMOS technology 1 Closed-loop FES 1