Ex parte FORDYCE - Page 2

          Appeal No. 96-2551                                                          
          Application 08/037,767                                                      

           102(b).  No claims have been indicated as allowable.  We reverse          
          both grounds of rejection.                                                  

                    The claimed subject matter is a gate drive for rapidly            
          turning on and off a high current capacity power switch, such as            
          an insulated gate bipolar transistor in an inverter operated in a           
          pulse-width modulated mode of operation.  Claim 1 reads as                  
                    1.  A drive circuit for a power switching                         
                    device, comprising:                                               
                         a transformer having a primary winding and a                 
                    secondary winding across which secondary pulses of first          
                    and second polarities and first and second magnitudes             
                    are developed when input pulses of opposing polarities            
                    are provided to the primary winding;                              
                         a full-wave rectifier bridge having first and                
                    second nodes coupled to the secondary winding and third           
                    and fourth nodes;                                                 
                         first and second capacitors connected in series              
                    between the third and fourth nodes;                               
                         first and second controlled switches coupled                 
                    between a control electrode of the power switching                
                    device and the first and second capacitors,                       
                    respectively, each controlled switch having a control             
                    electrode coupled to the secondary winding of the                 


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Last modified: November 3, 2007