Apple Inc.
Stacked resonant structures for wireless power systems

Abstract:

A wireless power system has wireless power transmitting and receiving devices. The transmitting and receiving devices convey wireless power using stacked resonant structures. The stacked resonant structures are self-resonant and have a parallel-coupled inductance and capacitance. The structures include a magnetic core having a central post and stacked ceramic layers within the magnetic core and laterally surrounding the central post. The structures include interleaved first and second sets of antiparallel-oriented C-shaped conductive layers and are driven using drive traces. The drive traces are formed from one of the C-shaped conductive layers or from conductive traces on a drive printed circuit board that underlies the stacked ceramic layers. The traces include one or more loops running around the central post. Host circuitry for the structures may have a central tap terminal coupled to the traces. If desired, a shield layer may overlap the conductive layers.