Electronic filter assembly

Abstract

A filter assembly, comprising first and second terminal caps in opposing relation to each other. The caps are physically and electrically coupled to each other. First and second circuit boards are physically coupled to the first cap. The first circuit board includes—(i) front and rear surfaces, (ii) a first circuit located on either or both of the front and rear surfaces, (iii) a ground lead connected to the first circuit, and (iv) a first electrical terminal coupled to the first circuit. The second circuit board includes—(i) front and rear surfaces, (ii) a second circuit located on either or both of the front and rear surfaces, (iii) a ground lead connected to the second circuit, and (iv) a second electrical terminal coupled to the second circuit. The first and second circuits are electrically coupled to each other, and each are electrically coupled to the first terminal cap via the ground leads. The circuit boards are positioned substantially parallel to each other. The terminals extend into and are operatively supported inside the terminal caps, respectively.

What is claimed is:  
     
         1 . A filter assembly, comprising: 
 first and second terminal caps disposed along a longitudinal axis in opposing relation to each other, said first and said second terminal caps being physically and electrically coupled to each other;    a first circuit board physically coupled to said first terminal cap, said first circuit board including—(i) front and rear surfaces, (ii) a first filter circuit located on either or both of the front and the rear surfaces, (iii) a ground contact electrically coupled to the first filter circuit and to said first terminal cap, and (iv) a first filter terminal electrically coupled to the first filter circuit; and    a second circuit board physically coupled to said first terminal cap, said second circuit board including—(i) front and rear surfaces, (ii) a second filter circuit located on either or both of the front and the rear surfaces, (iii) a ground contact electrically coupled to the second filter circuit and to said first terminal cap, and (iv) a second filter terminal electrically coupled to the second filter circuit,    the first and the second filter circuits being electrically coupled to each other, and each of the circuits being electrically coupled to said first terminal cap via the ground contacts such that the circuits have a common electrical ground through the first terminal cap,    said first and said second circuit boards being positioned substantially parallel to each other and to the longitudinal axis between said first and said second terminal caps, the front surface of said first circuit board substantially facing the front surface of said second circuit board,    the first terminal extending into and being operatively supported inside said first terminal cap, and the second terminal extending into and being operatively supported inside said second terminal cap.    
     
     
         2 . The filter assembly of  claim 1 , wherein said first and said second circuit boards are directly connected to said first terminal cap.  
     
     
         3 . The filter assembly of  claim 1 , wherein said first and said second circuit boards are mated with said first terminal cap, to establish a secure physical and electrical connection.  
     
     
         4 . The filter assembly of  claim 3 , wherein said first and said second circuit boards each include a mating end, the ground contacts of said first and said second circuit boards being located at the mating ends, respectively, and wherein said first terminal cap contains first and second grooves configured to receive, in a tight press fit, the mating ends of said first and said second circuit boards, respectively, whereby the tight press fit secures said first and said second circuit boards in position.  
     
     
         5 . The filter assembly of  claim 4 , wherein said first circuit board includes a plurality of ground contacts electrically connected to the first filter circuit, the ground contacts being located at the mating end of the first circuit board and being in direct physical contact with the first groove of said first terminal cap.  
     
     
         6 . The filter assembly of  claim 5 , wherein said second circuit board includes a plurality of ground contacts electrically connected to the second filter circuit, the ground contacts being located at the mating end of the second circuit board and being in direct physical contact with the second groove of said first terminal cap.  
     
     
         7 . The filter assembly of  claim 1 , wherein the first filter circuit is located on the front surface of said first circuit board, and wherein the second filter circuit is located on the front surface of said second circuit board.  
     
     
         8 . The filter assembly of  claim 1 , wherein a metal ground plane is situated on the front surface of said first circuit board, and wherein the first filter circuit is located on the rear surface of said first circuit board, whereby the ground plane establishes a certain degree of electromagnetic shielding between the first and the second filter circuits.  
     
     
         9 . The filter assembly of  claim 1 , wherein a metal ground plane is situated on the front surface of said second circuit board, and wherein the second filter circuit is located on the rear surface of said second circuit board, whereby the ground planes of said first and said second circuit boards establish a certain degree of electromagnetic shielding between the first and the second filter circuits.  
     
     
         10 . The filter assembly of  claim 1 , wherein the first filter circuit includes a plurality of inductors, and wherein at least one of the inductors is printed on either the front or the rear surface of said first circuit board.  
     
     
         11 . The filter assembly of  claim 1 , wherein the first circuit includes a plurality of inductors and a plurality of capacitors, and wherein the plurality of inductors are printed on the rear surface and the plurality of capacitors are located on the front surface of said first circuit board.  
     
     
         12 . The filter assembly of  claim 11 , wherein the second circuit includes a plurality of inductors and a plurality of capacitors, and wherein the plurality of inductors are printed on the rear surface and the plurality of capacitors are located on the front surface of said second circuit board.  
     
     
         13 . The filter assembly of  claim 1 , wherein said second terminal cap extends to and is directly connected to said first terminal cap, to form a filter housing which encloses said first and said second circuit boards in an interior volume.  
     
     
         14 . The filter assembly of  claim 13 , wherein the connection between said second and said first terminal caps is substantially sealed by solder received in a groove contained in said first cap.  
     
     
         15 . The filter assembly of  claim 13 , wherein said first terminal cap contains a first terminal passage between the interior volume of the filter housing and the exterior of said filter assembly, the first terminal extending through the first terminal passage, and wherein said first terminal cap includes a sealing member secured in and substantially closing the first passage, said sealing member containing a hole through which the first terminal tightly fits.  
     
     
         16 . The filter assembly of  claim 15 , wherein said second terminal cap contains a second terminal passage between the interior volume of the filter housing and the exterior of said filter assembly, the second terminal extending through the second terminal passage, and wherein said second terminal cap includes a sealing member secured in and substantially closing the second passage, said sealing member containing a hole through which the second terminal tightly fits.  
     
     
         17 . The filter assembly of  claim 16 , wherein the sealing member of said second terminal cap is an elongated insulator, and wherein the second filter terminal is a collet terminal.  
     
     
         18 . The filter assembly of  claim 17 , further comprising an o-ring seated inside said second terminal passage, between the insulator and said second terminal cap.  
     
     
         19 . The filter assembly of  claim 17 , wherein said collet terminal has a barb protruding therefrom, which penetrates the insulator from inside the hole of the insulator.  
     
     
         20 . A filter assembly, comprising: 
 first and second terminal caps disposed along a longitudinal axis in opposing relation to each other, said first and said second terminal caps being physically and electrically coupled to each other; and    a circuit board mated with said first terminal cap, said circuit board including—(i) front and rear surfaces, (ii) a filter circuit located on either or both of the front and the rear surfaces, (iii) a ground contact electrically coupled to the circuit and to said first terminal cap, and (iv) first and second filter terminals electrically coupled to the circuit,    the filter circuit being electrically coupled to said first terminal cap via the ground contact, such that the circuit is grounded through the first terminal cap, said circuit board being positioned substantially parallel to the longitudinal axis between said first and said second terminal caps, the first and the second terminals extending into and being operatively supported inside said first and said second terminal caps, respectively.    
     
     
         21 . A filter assembly, comprising: 
 first and second terminal caps arranged in opposing relation to each other, said first cap being directly connected to said second cap to form a filter housing which defines an interior volume, said first cap containing an external groove, and the connection between said first and said second caps being substantially sealed by solder received in the groove, said first and said second caps containing first and second terminal passages, respectively, between the interior volume and the exterior of said filter assembly;    a filter circuit mounted inside said filter housing;    first and second filter terminals electrically coupled to said filter circuit, said first and said second terminals extending through and being operatively supported inside the first and the second terminal passages, respectively;    a first sealing member secured in and substantially closing the first terminal passage, said sealing member containing a hole through which the first terminal tightly fits;    a second sealing member secured in and substantially closing the second terminal passage, said second sealing member containing a hole through which the second terminal tightly fits; and    an o-ring seated inside said second terminal passage, between the second sealing member and said second terminal cap.    
     
     
         22 . The first assembly of  claim 21 , wherein said second filter terminal is a collet terminal having a barb protruding therefrom, said barb penetrating said second sealing member from inside the hole of said second sealing member.  
     
     
         23 . An electronic filter assembly of the type that includes a female terminal cap having a fitting portion and containing a terminal passage through the fitting portion, and a collet assembly secured in and substantially closing the terminal passage of said female terminal cap, wherein said collet assembly comprises: 
 an insulator, made from a single piece of insulator material, containing a bore therethrough;    a collet terminal extending through the bore of the insulator; and    a seal located inside the terminal passage of said female terminal cap, between the collet terminal and said female terminal cap.    
     
     
         24 . The electronic filter assembly of  claim 23 , wherein the collet terminal has at least one barb which penetrates the insulator material of the insulator, to help prevent moisture from entering said filter housing between the bore of the insulator and the collet terminal.  
     
     
         25 . The electronic filter assembly of  claim 23 , wherein the insulator of said collet assembly has a substantially cone-shaped nose portion.