Implantable medical device including a molded planar transformer

Abstract

The present disclosure provides methods and techniques associated with a planar transformer for an apparatus. The planar transformers include a substrate carrying electronic components and a continuous core that is formed by distributing the encapsulant material uniformly around the substrate unit to define a consistent cross-sectional area for the magnetic path. The electronic components include primary windings and secondary windings associated with the transformer. In some embodiments, the encapsulant material is molded to seals air gaps to the substrate unit.

1 - 17 . (canceled) 
     
     
         18 . An implantable medical device having electronic circuitry operable to perform a therapeutic and/or monitoring function, comprising:
 a battery;   a capacitor; and   a transformer coupled to the battery and the capacitor, wherein the transformer includes:
 a substrate unit having electronic components and including primary and secondary windings embedded within the substrate unit; 
 a core encapsulating the substrate unit, wherein the core includes a unitary core having a unitary core that are molded to eliminate an air gap therebetween. 
   
     
     
         19 . The implantable medical device of  claim 18 , wherein the configuration of the unitary core is selected based on a performance criteria for the transformer. 
     
     
         20 . The implantable medical device of  claim 18 , wherein the unitary core comprises a polymer bonded magnetic compound. 
     
     
         21 . A transformer assembly, comprising:
 a substrate unit comprising electronic components embedded in a top surface of the substrate unit, wherein at least one electronic component comprises primary and secondary windings;   an upper magnetic core placed over the top surface of the substrate unit and the electronic components;   a lower magnetic core placed over a bottom surface of the substrate unit; and   an encapsulant material dispensed over exterior surfaces of the upper magnetic core and the top surface of the substrate unit.   
     
     
         22 . The assembly of  claim 21 , further comprising encapsulant material disposed over exterior surfaces of the lower magnetic core. 
     
     
         23 . The assembly of  claim 21 , further comprising an adhesive material disposed between the lower magnetic core and the bottom surface of the substrate unit such that the lower magnetic core is attached to the substrate unit. 
     
     
         24 . The assembly of  claim 21 , wherein the encapsulant material dispensed over the exterior surfaces of the upper magnetic core and the top surface of the substrate unit is formed to expose an exterior surface of the upper magnetic core that is parallel to the top surface of the substrate unit. 
     
     
         25 . The assembly of  claim 21 , wherein the encapsulant material dispensed over the exterior surfaces of the upper magnetic core and the top surface of the substrate unit is also dispensed between one or more gaps formed between the substrate unit and the upper magnetic core. 
     
     
         26 . The assembly of  claim 21 , further comprising a pair of terminal connectors coupled to the primary and second windings of the at least one electronic component. 
     
     
         27 . The assembly of  claim 26 , wherein the pair of terminal connectors is formed at least partially on the bottom surface of the substrate unit. 
     
     
         28 . The assembly of  claim 21 , further comprising circuitry coupled to the substrate unit. 
     
     
         29 . The assembly of  claim 28 , wherein the circuitry is disposed on the top surface of the substrate unit adjacent the upper magnetic core. 
     
     
         30 . An implantable medical device comprising the transformer assembly of  claim 21 . 
     
     
         31 . A method of forming a transformer assembly, comprising:
 providing a substrate comprising a substrate unit, wherein the substrate unit comprises electronic components disposed on a top surface of the substrate unit, wherein at least one electronic component of the substrate unit comprises primary and secondary windings;   mounting the substrate to a first surface of an adhesive material;   mounting a carrier plate to a second surface of the adhesive material;   placing an upper magnetic core over the top surface of the substrate unit and the electronic components;   dispensing encapsulant material over exterior surfaces of the upper magnetic core and the top surface of the substrate unit;   curing the encapsulant material;   grinding the encapsulant material to reduce a thickness of the encapsulated assembly;   detaching the substrate from the adhesive material and the carrier plate; and   placing a lower magnetic core over a bottom surface of the substrate unit.   
     
     
         32 . The method of  claim 31 , wherein the primary and secondary windings of the at least one electronic component of the substrate unit are coupled to terminal connectors that are formed on the bottom surface of the substrate. 
     
     
         33 . The method of  claim 32 , further comprising connecting a plurality of conductive pads to the substrate such that a conductive pad of the plurality of conductive pads is coupled to each terminal connector. 
     
     
         34 . The method of  claim 31 , wherein grinding the encapsulant material further comprises grinding the upper magnetic core. 
     
     
         35 . The method of  claim 31 , wherein placing the lower magnetic core on the bottom surface of the substrate unit comprises attaching the lower magnetic core to the bottom surface of the substrate unit. 
     
     
         36 . The method of  claim 31 , further comprising:
 dispensing an encapsulant material over exterior surfaces of the lower magnetic core and the bottom surface of the substrate unit;   curing the encapsulant material dispensed over the exterior surfaces of the lower magnetic core and the bottom surface of the substrate unit; and   grinding the encapsulant material dispensed over the exterior surfaces of the lower magnetic core and the bottom surface of the substrate unit.   
     
     
         37 . The method of  claim 36 , wherein the substrate comprises a plurality of substrate units, wherein the method further comprises singulating the plurality of substrate units into individual substrate units.