Title:  Inductively Coupled CMOS Power Receiver for Embedded Microsensors

Committee: 

Dr. Rincon-Mora, Advisor     

Dr. Divan, Chair

Dr. Wang

Abstract:

The objective of this research is to study, evaluate, design, build, test, and assess an inductively coupled CMOS power receiver for embedded microsensors that draws power from a radially distant source to replenish a tiny onboard battery. Coupling in these applications is very weak because the separation between the transmitter and receiver coils far exceeds the radius of the coils. Such a tiny, weakly coupled, and often misaligned receiver coil only couples millivolts, so drawing power is challenging. Applying a high voltage boosts coil current and, in consequence, outputs more power, but only to the extent that the circuit’s breakdown voltage allows. Plus, tiny coils are so resistive that ohmic losses also constrain output power. This research therefore proposes to study how breakdown voltage and losses limit output power, and under those conditions, how a receiver can output the highest power possible. With this understanding, the research will then explore and develop a low-loss CMOS power receiver with a microwatt controller that can operate the system so output power is maximally high. The ultimate goal is to build a power-receiver system that can draw and output more power than the state of the art, and that way, expand the functionality, life, and application space of emerging biomedical implants and structurally embedded microsensors.