Magnetically coupled galvanically isolated communication using lead frame

Abstract

An integrated circuit package includes a lead frame and an encapsulation that substantially encloses the lead frame. The lead frame further includes a first conductor comprising a first conductive loop and a second conductor galvanically isolated from the first conductor, proximate to and magnetically coupled to the first conductive loop to provide a communication link between the first and second conductor. The second conductor includes a first conductive portion, a second conductive portion, and a wire coupling together the first conductive portion and the second conductive portion.

What is claimed is: 
     
         1 . An integrated circuit package, comprising:
 an encapsulation; and   a lead frame, a portion of the lead frame disposed within the encapsulation, the lead frame comprising:
 a first conductive loop disposed substantially within the encapsulation; 
 a second conductive loop disposed substantially within the encapsulation and substantially all of the second conductive loop is outside of the first conductive loop; and 
 a galvanic isolator coupled to the first conductive loop such that there is galvanic isolation between the first and the second conductive loops,
 wherein the first and second conductive loops are configured to form a magnetically coupled communication link. 
 
   
     
     
         2 . The integrated circuit package of  claim 1 , further comprising:
 a first circuit coupled to the first conductive loop; and   a second circuit coupled to the second conductive loop,
 wherein one of the first and second circuits is configured to control properties of a transmitter current to produce a changing magnetic field in proximity to a corresponding one of the first and second conductive loops, thereby inducing a voltage that is generated across an other one of the first and second conductive loops that is subjected to the changing magnetic field and results in a current flow in the other one of the inner and outer conductive loops, and 
 wherein the other one of the first and second circuits is configured to receive an electrical parameter induced by the one of the first and second circuits. 
   
     
     
         3 . The integrated circuit package of  claim 2 , wherein the galvanic isolator comprises a conductive element connecting parts of the first loop disposed within the encapsulation. 
     
     
         4 . The integrated circuit package of  claim 3 , wherein the conductive element comprises a bond wire. 
     
     
         5 . The integrated circuit package of  claim 3 , wherein the electrical parameter is selected from a group comprising voltage and current. 
     
     
         6 . The integrated circuit package of  claim 3 , wherein one of the first and second circuit comprises a transmitter circuit, and
 an other of the first and second circuit comprises a receiver circuit.   
     
     
         7 . The integrated circuit package of  claim 6 , wherein the first conductive loop and the second conductive are positioned to enclose a maximum common magnetic field area. 
     
     
         8 . The integrated circuit package of  claim 6 , further comprising:
 a tiebar attached to the leadframe; and   a third conductive loop coupled to one of the first and second conductive loops and the tiebar,
 wherein the third conductive loop is configured to provide noise cancellation. 
   
     
     
         9 . The integrated circuit package of  claim 3 , wherein each of the first and the second circuit comprises a transceiver circuit. 
     
     
         10 . The integrated circuit package of  claim 9 , wherein the first conductive loop and the second conductive loop have approximately the same dimensions. 
     
     
         11 . The integrated circuit package of  claim 9 , wherein the first conductive loop and the second conductive loop are physically symmetric. 
     
     
         12 . The integrated circuit package of  claim 3 , further comprising:
 a tiebar attached to the leadframe; and   a third conductive loop coupled to one of the first and second conductive loops and the tiebar,
 wherein the third conductive loop is configured to provide noise cancellation. 
   
     
     
         13 . The integrated circuit package of  claim 3 , wherein the properties of the transmitter current are selected from a group comprising magnitude and rate of change of the transmitter current. 
     
     
         14 . The integrated circuit package of  claim 13 , wherein the rate of change of the transmitter current corresponds to rising and falling slopes defined by a pulse waveform. 
     
     
         15 . The integrated circuit package of  claim 13 , wherein for an induced voltage, the rising slope corresponds to a positive amplitude and the falling slope corresponds to a negative amplitude. 
     
     
         16 . The integrated circuit package of  claim 2 , further comprising:
 a tiebar attached to the leadframe; and   a third conductive loop coupled to one of the first and second conductive loops and the tiebar,   wherein the third conductive loop is configured to provide noise cancellation.   
     
     
         17 . The integrated circuit package of  claim 2 , wherein the integrated circuit package is configured to be used in a synchronous flyback switch mode power converter with secondary control.