[2025] A power management unit for inductive wireless power transfer

Future brain-machine interfaces require fully integrated electronics that can be powered wirelessly, both for patient safety and long-term reliability. Inductive power transfer is generally used for these types of implants. 

A limiting factor in implants is tissue heating. The power radiated by the transmitter is absorbed in the body and adds to the heat that’s produced by the implant itself. A main challenge is to reduce the total power absorbed in the tissue while providing sufficient power to the implant.

Current power management units (PMU) typically rely on a rectifier and linear regulator combination to provide a stable supply to the implant. The dropout of a linear regulator requires the input voltage to be higher than the output voltage, which corresponds to a minimum amount of power that needs to be sent from the transmitter. This constraint limits the achievable efficiency and input range flexibility. Moreover, modern intelligent closed-loop implants benefit from lower technology nodes, which further limits the workable voltage range, complicating the PMU design.

Assignment

Your assignment, if you choose to accept it, is to develop an on-chip PMU that breaks the linear regulator limitation by fully integrating a DC-DC converter on-chip in 28nm, ideally, directly combined with a rectifier to avoid cascaded losses in a low-area solution. 

Requirements

Required courses:

• Power conversion techniques in CMOS technology

• Analog Circuit Design Fundamentals

• Measurement and Instrumentation

• Analog CMOS 1

Recommended courses:

• Analog Integrated Circuit Design

• Analog CMOS 2

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Last modified: 2025-03-10