A closed-loop inductive power control system for an instrumented strain sensing tibial implant

Area of Science:

• Biomedical Engineering
• Implantable Devices
• Wireless Power Transfer

Background:

• Inductively-powered implantable devices face performance issues due to power variations from coil misalignment.
• Maintaining stable power is crucial for reliable remote data acquisition from implanted sensors.

Purpose of the Study:

• To propose and implement a closed-loop power control system for inductively-powered biomedical devices.
• To improve the performance and reliability of the Subject-Carried Implant Monitoring Inductive Telemetric Ambulatory Reader (SCIMITAR).

Main Methods:

• A closed-loop power control system was developed and integrated into the SCIMITAR device.
• The system adaptively adjusts energizer output power using feedback from a demodulator.
• The system was tested for remote strain data acquisition from an instrumented ovine tibia implant.

Main Results:

• The feedback control system effectively suppressed power variations caused by coil misalignment.
• The functional range of the device was extended in both axial and planar directions.
• Stable power delivery was achieved despite positional changes between coils.

Conclusions:

• The proposed closed-loop power control system significantly enhances the stability and reliability of inductively-powered implantable devices.
• This technology improves the performance of remote monitoring systems like SCIMITAR, especially in dynamic conditions.
• Adaptive power control is essential for overcoming challenges in wireless power transfer for biomedical implants.