As reported by PubMed in their article “Effect of the metallic seal of a hermetic enclosure on the induction of power to an implant,” most neuroprostheses utilizing integrated circuits protect their chip components within a hermetic package. Currently, no satisfactory sealing method exists that does not involve metals, resulting in the use of an electrically conducting ring. When induction is used to supply power to these devices, this ring acts as a ‘short-circuited turn,’ affecting the performance of the inductive link.
The article presents a theoretical model where the metallic seal functions as a tertiary inductance, coupled with the primary and secondary inductances. This tertiary inductance has a finite quality factor (Q). Equations derived from this model provide formulae for calculating gain and efficiency, particularly when the carrier frequency matches the resonant frequency of both primary and secondary circuits. Gain curves plotted from these formulae illustrate the impact of the seal on the inductive link’s performance.
However, the study indicates that general solutions are necessary for the theory to be practically useful. Despite the challenges, the findings offer valuable insights into optimizing the power induction process in neuroprosthetic devices.
Enhancing the efficiency and reliability of hermetic enclosures for implants involves understanding the complexities of metallic seals and their impact on inductive power transfer. This ongoing innovation improves the performance of neuroprostheses.
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Article with all rights reserved, courtesy of pubmed.ncbi.nlm.nih.gov