Transcript Low Power Artificial Retina

Low Power Artificial Retina
By
Duha Jabakhanji
Objectives
• Design a subretinal implant.
• Design a temperature variable supply
voltage (TVS).
• Integrate the two designs together.
• Lower power with increasing
temperature.
• Examine the effects of temperature on
ocular implants.
Challenges
• Simulating the artificial retina:
photodiode needed.
• Simulating a pixel matrix.
• Designing the TVS and integrating it
with the artificial retina.
Design: Photodiode
• Photodiode:
– Accurately models a
photodiode.
– Vary the current
source.
Design: Pixel
One pixel from M. Mazza, P. Renaud, D. C.
Bertrand, and A. M. Ionescu, “CMOS Pixels
for Subretinal Implantable Prothesis” .
Implemented in 0.13u technology.
• Used the LICOS design.
Design: Sensor
• Temperature sensor:
– Used NPN BJT for
better resolution.
Design: TVS
• The proposed
design was too
large.
• ADC too large to
implement.
• A subtractor was
used instead.
Solar
Panel
Control
Circuit
A/D
converter
Temperature
Sensor
VDD
Design: TVS
Results: 10X10 array
Conclusion
•
•
•
•
TVS Artificial Retina was a success.
Provides a good diagnostic tool.
Is self regulatory.
Designers should take into
consideration varying temperatures and
design the implant to withstand it.
• Heat damage could be an issue in some
cases.