Design of an electrical nerve stimulator using wireless power transmission through NFC
Document typeMaster thesis
Rights accessOpen Access
Electrical stimulation has been proved to be an effective method to speed up the recovery process of a peripheral nerve that has been badly injured. In this work it is designed the circuitry for a hypothetical implanted device that can be powered by the presence of an NFC field emitted by a nearby smartphone, with the aim to deliver the pulses required by the electrical stimulation process. The device would consist of a NFC-compatible loop antenna, the integrated circuit, some external energy-storing capacitors to ensure a stable voltage supply and pulse delivery into the nerve, and the output of the chip would be connected directly into the nerve. Research about the possibilities that can bring NFC technology to biomedical applications has been made, and the feasibility of the implementation of this protocol for the device mentioned has been studied by making experimental measurements about the power transfer process from an NFC reader to a passive tag. By these means, the amount of power that it can be collected by a reader has been measured, and the factors affecting the inductive coupling link have been studied. Then, a circuit able to use power coming from an NFC loop antenna, rectify the signal and provide a supply voltage for the rest of the circuit components has been designed. This circuit is able to detect a code given by the user, which acts as the start signal for the pulse delivery into the nerve. It also takes the 13.56 MHz original input signal and generates a clock, which is used to generate pulses at the desired frequency for the application.
Design of an interface integrated circuit to an ion pump. The circuit will be able to harvest energy from Near Field Communication (NFC) technology, rectify the signal, regulate it in order to generate a stable supply voltage for the circuit and then produce the voltage required by the ion pump.