Filtered feedthrough assembly for implantable medical electronic devices

Abstract

A filtered feedthrough assembly for an implantable medical device comprises a ferrule, an electrical insulator coupled to the ferrule by a connection element, a plurality of feedthrough conductors extending through the electrical insulator, a printed circuit board (PCB), and plurality of capacitors. The PCB is coupled to the ferrule or the electrical insulator, and includes one or more ground layers and a plurality of vias. The connection element is electrically coupled to the ground layer through the vias. The capacitor has a ground terminal electrically coupled to the ground layer through at least one of the vias, and a conductor terminal electrically coupled to the feedthrough conductor.

1 . A filtered feedthrough assembly for an implantable medical device, comprising:
 a ferrule configured to be connected to a metal case of the implantable medical device;   a feedthrough conductor extending from outside the metal case to inside the metal case;   a printed circuit board (PCB) coupled to the ferrule, wherein the PCB includes a plurality of ground layers and a plurality of vias in electrical contact with the plurality of ground layers;   a connection element electrically coupled to the ferrule and the ground layer of the PCB through the vias; and   a filter circuit electrically coupled to the feedthrough conductor and electrically coupled to the ground layer of the PCB through at least one of the vias.   
     
     
         2 . The filtered feedthrough assembly of  claim 1 , further comprising a conductive epoxy disposed within at least one of the vias to electrically couple the connection element to the ground layer. 
     
     
         3 . The filtered feedthrough assembly of  claim 1 , wherein the PCB includes a plurality of ground layers and wherein the vias traverse the plurality of ground layers. 
     
     
         4 . The filtered feedthrough assembly of  claim 3 , further comprising a plurality of feedthrough conductors extending through the electrical insulator, and a plurality of capacitors each associated with one of the plurality of feedthrough conductors. 
     
     
         5 . The filtered feedthrough assembly of  claim 4 , wherein each capacitor of the plurality of capacitors includes a ground terminal electrically coupled to the plurality of ground layers by at least one of the vias, and a conductor terminal electrically coupled to a respective one of the feedthrough conductors. 
     
     
         6 . The filtered feedthrough assembly of  claim 3 , further comprising at least one ground pin electrically coupled to the ground layers. 
     
     
         7 . The filtered feedthrough assembly of  claim 6 , wherein the number of ground pins equals the number of ground layers of the PCB. 
     
     
         8 . The filtered feedthrough assembly of  claim 1 , wherein the connection element is a gold braze material. 
     
     
         9 . The filtered feedthrough assembly of  claim 1 , wherein a conductive epoxy is disposed within at least one of the plurality of vias to contact the connection element so as to provide a continuous electrical path between the connection element and the ground layer. 
     
     
         10 . The filtered feedthrough assembly of  claim 1 , including an electrical insulator arranged around the feedthrough conductor, and wherein the connection element is a gold braze material disposed so as to attach the electrical insulator to the ferrule. 
     
     
         11 . An implantable medical device comprising:
 a metallic housing;   a ferrule connected to the metallic housing;   a feedthrough conductor extending from outside the metallic housing case to inside the metallic housing;   a printed circuit board (PCB) coupled to the ferrule, wherein the PCB includes a plurality of ground layers, and a plurality of vias traversing the ground layers;   a connection element electrically coupled to the ferrule and the ground layer of the PCB through the vias; and   a filter circuit electrically coupled to the feedthrough conductor and electrically coupled to the ground layer of the PCB through at least one of the vias.   
     
     
         12 . The implantable medical device of  claim 11 , wherein a conductive epoxy is disposed within the plurality of vias so as to electrically couple the electrically conductive connection element to the plurality of ground layers. 
     
     
         13 . The implantable medical device of  claim 11 , wherein the electrically conductive connection element is a gold braze material, and wherein the conductive epoxy is disposed within at least one of the plurality of vias to contact the gold braze material so as to provide a plurality of electrical paths electrically coupling the gold braze material to the plurality of ground layers. 
     
     
         14 . The implantable medical device of  claim 11 , further comprising at least one ground pin electrically coupled to the plurality of ground layers. 
     
     
         15 . The implantable medical device of  claim 14 , wherein the at least one ground pin is coupled to the plurality of ground layers by a conductive epoxy injected into at least one of the plurality of vias. 
     
     
         16 . The implantable medical device of  claim 11 , wherein the plurality of ground layers comprises one of four ground layers, three ground layers, and two ground layers. 
     
     
         17 . The implantable medical device of  claim 11 , including an insulator arranged around the feedthrough conductor. 
     
     
         18 . The method of making a filtered feedthrough assembly for an implantable medical device, the method comprising:
 providing a PCB having a plurality of ground layers and a plurality of vias extending through the ground layers;   disposing a plurality of filter circuits on the PCB, wherein a filter circuit is electrically coupled to the plurality of ground layers through at least one of the vias;   arranging a plurality of feedthrough conductors to each pass through a plurality of ferrules, wherein each ferrule includes an electrically conductive connection element;   electrically coupling each of the feedthrough conductors to a filter circuit; and   electrically coupling the connection element of each of the ferrules to the plurality of ground layers through the vias.   
     
     
         19 . The method of  claim 18 , including coupling an electrical insulator to each of the ferrules using the connection element of each of the ferrules. 
     
     
         20 . The method of  claim 18 , including disposing a conductive material in the plurality of vias so as to contact the connection element of each of the ferrules and provide a plurality of parallel electrical paths from the connection element of each of the ferrules to the plurality of ground layers.