13.56 mhz multi-mode rectifier circuit for wirelessly powered implantable medical devices

Engür, Yasemin
Implantable devices are becoming popular with the improvements of nanotechnology. The implants require huge amount of power for operation within limited volume. This power requirement can be satisfied by implantable batteries. However, the limited energy of batteries restricts their lifetime, so they need to be recharged for long lasting operation. The charging operation can be done wirelessly with RF coils. These coils offer certain advantages over other wireless power transmission techniques such as high-power transmission and lower area occupancy. In this thesis, an interface circuit for wireless power transmission in RF domain is designed. The interface circuit is responsible for charging the rechargeable battery which is used to power up the implantabledevices. For that purpose, a magnet free coil pair is designed, and extended coupling range multi-mode rectifier circuits are implemented. One of the rectifier circuits is named as double mode rectifier. The maximum power conversion efficiency of double mode rectifier is 72.4% for high coupling levels(voltage mode operation) and 38.6% for low coupling levels (current mode operation)while charging a 3.3V load. Inthe improved version of double mode rectifier, which is triple mode rectifier circuit, the maximum power conversion efficiency of each operation mode is 51.78%, 82.49% and 89.34% forlow coupling viratios(current mode),middle couplings(half wave mode)and high coupling ratios (voltage mode)respectively while charging a 3.3 V load.


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Citation Formats
Y. Engür, “13.56 mhz multi-mode rectifier circuit for wirelessly powered implantable medical devices,” M.S. - Master of Science, Middle East Technical University, 2020.