Surface mount resistors as heat transfer augmentation devices

Abstract

The present invention provides a heat transfer augmentation method and device for use on a printed circuit board. The inventive device comprises one or more elements having high impedance that are attached to traces on a printed circuit board, thus permitting heat transfer without allowing the device to affect the electrical circuit on the board. The elements can be surface mount resistors that conduct heat more efficiently than does the printed circuit board insulator material, such as resistors having alumina or aluminum nitride substrates. The inventive device and method is thus compatible with standard printed circuit board assembly procedures, is inexpensive, and has a smaller foot print on the circuit board than prior art heat transfer augmentation devices.

What is claimed is:  
     
         1 . A heat transfer augmentation device for mounting between a first position on a first trace and a second position on a nearby second trace on a printed circuit board that supports an electrical circuit having a circuit impedance, where said circuit generates a first temperature difference between said two positions, said device comprising: 
 an element disposed between said two positions and having an impedance that is at least 100 times greater than said circuit impedance, where the element has thermal properties that result in a temperature difference between said two positions that is less than said first temperature difference.    
     
     
         2 . The heat transfer device of  claim 1 , wherein said impedance that is from 100 to 1000 times greater than said circuit impedance.  
     
     
         3 . The heat transfer device of  claim 1 , wherein said element is a surface mount resistor.  
     
     
         4 . The heat transfer device of  claim 3 , wherein said surface mount resistor has a substrate, where the thermal conductivity of said substrate is greater than the thermal conductivity of said printed circuit board.  
     
     
         5 . The heat transfer device of  claim 1 , wherein said surface mount resistor has a substrate of alumina.  
     
     
         6 . The heat transfer device of  claim 1 , wherein said surface mount resistor has a substrate of aluminum nitride.  
     
     
         7 . A heat transfer augmentation device for mounting between a first position on a first trace and a second position on a nearby second trace on a printed circuit board that supports an electrical circuit having a circuit impedance, said device comprising: 
 a surface mount resistor having an impedance that is at least 100 times greater than said circuit impedance.    
     
     
         8 . The heat transfer device of  claim 7 , wherein said impedance that is from 100 to 1000 times greater than said circuit impedance.  
     
     
         9 . The heat transfer device of  claim 7 , wherein said surface mount resistor has a substrate of alumina.  
     
     
         10 . The heat transfer device of  claim 7 , wherein said surface mount resistor has a substrate of aluminum nitride.  
     
     
         11 . A method for augmenting the heat transfer between a first position on a first trace and a second position on a nearby second trace on a printed circuit board that supports an electrical circuit having an impedance, where said circuit, when operating, generates a first temperature difference between said two positions, said method comprising: 
 mounting an element on said printed circuit board between said two positions, where said element has an impedance that is at least 100 times the circuit impedance, and where said circuit, when operating with said mounted element, generates a second temperature difference between said two positions that is less than said first temperature difference.    
     
     
         12 . The method of  claim 11 , wherein said mounting is mounting an element with an impedance that is from 100 to 1000 times greater than said circuit impedance.  
     
     
         13 . The method of  claim 11 , wherein said mounting is mounting a surface mount resistor.  
     
     
         14 . The method of  claim 13 , wherein said surface mount resistor has a substrate, where the thermal conductivity of said substrate is greater than the thermal conductivity of said printed circuit board.  
     
     
         15 . The method of  claim 13 , wherein said surface mount resistor has a substrate of alumina.  
     
     
         16 . The method of  claim 13 , wherein said surface mount resistor has a substrate of aluminum nitride.  
     
     
         17 . A method for augmenting the heat transfer between a first position on a first trace and a second position on a nearby second trace on a printed circuit board that supports an electrical circuit having an impedance, where said circuit, when operating, generates a first temperature difference between said two positions, said method comprising: 
 mounting a surface mount resistor between said two positions having an impedance that is at least 100 times greater than said circuit impedance.    
     
     
         18 . The heat transfer device of  claim 17 , wherein said mounting is mounting a surface mount resistor having an impedance that is from 100 to 1000 times greater than said circuit impedance.  
     
     
         19 . The heat transfer device of  claim 17 , wherein said mounting is mounting a surface mount resistor having a substrate of alumina.  
     
     
         20 . The heat transfer device of  claim 17 , wherein said mounting is mounting a surface mount resistor having a substrate of aluminum nitride.