Active discharge systems and methods

Abstract

To avoid charge accumulation on capacitive connections to implanted electrodes during delivery of stimulation pulses, stimulation pulses are followed by active discharge pulses having opposite polarity of the stimulation pulses. The active discharge pulses preferably have at least one pulse attribute magnitude (e.g., duration, voltage, and/or current) different than a corresponding stimulation pulse and are preferably programmable. Approximately the same total net current flow is delivered during active discharge pulses as during the stimulation pulses, but in the opposite direction and optionally at a lower amplitude. In addition, by reducing the driving voltage and a variable load within the electrical path for delivery of the pulses, power dissipation during active discharge is preferably reduced.

1 . A system comprising: 
 an electrical pulse delivery circuit; and    a control circuit coupled to said electrical pulse delivery circuit and controlling said electrical pulse delivery circuit to provide output operation and active discharge operation, wherein said control circuit causes at least one of a pulse duration, a pulse voltage magnitude, and a pulse current magnitude to be different between a pulse of said output operation and a corresponding pulse of said active discharge operation.    
   
   
       2 . The system of  claim 1 , wherein said pulse of said active discharge operation has a pulse duration greater than a pulse duration of said pulse of said output operation.  
   
   
       3 . The system of  claim 2 , wherein said pulse of said active discharge operation has a pulse voltage magnitude less than a pulse voltage magnitude of said pulse of said output operation.  
   
   
       4 . The system of  claim 2 , wherein said pulse of said active discharge operation has a pulse current magnitude less than a pulse current magnitude of said pulse of said output operation.  
   
   
       5 . The system of  claim 1 , wherein said pulse of said active discharge operation delivers a same magnitude of net current as said pulse of said pulse of said output operation.  
   
   
       6 . The system of  claim 1 , wherein said electrical pulse delivery circuit comprises a fractional voltage converter providing said different pulse voltage magnitude between said pulse of said output operation and said pulse of said active discharge operation.  
   
   
       7 . The system of  claim 1 , wherein said control circuit provides programmable amplitude and duration with respect to at least one of said pulse of said output operation and said pulse of said active discharge operation.  
   
   
       8 . The system of  claim 1 , wherein said electrical pulse delivery circuit and said control circuit comprise a stimulator for delivering therapy to a patient, wherein said pulse of said output operation provides stimulation therapy.  
   
   
       9 . A system comprising: 
 an electrical pulse delivery circuit; and    a control circuit coupled to said electrical pulse delivery circuit and controlling said electrical pulse delivery circuit to provide an output pulse having a pulse attribute magnitude which is different than a pulse attribute magnitude of a corresponding active discharge pulse.    
   
   
       10 . The system of  claim 9 , wherein said control circuit controls said electrical pulse delivery circuit to provide an output pulse having at least two pulse attribute magnitudes which are different than pulse attribute magnitudes of a corresponding active discharge pulse.  
   
   
       11 . The system of  claim 9 , wherein said active discharge pulse delivers a same magnitude of net current as said output pulse.  
   
   
       12 . The system of  claim 9 , wherein said electrical pulse delivery circuit comprises a fractional voltage converter providing said different pulse attribute magnitude between said output pulse and said active discharge pulse.  
   
   
       13 . The system of  claim 9 , wherein said pulse attribute magnitude is different by at least one-to-two (1:2).  
   
   
       14 . A method comprising: 
 providing an output pulse having at least a first predetermined pulse attribute magnitude; and    providing an active discharge pulse having at least a second predetermined pulse attribute magnitude, wherein said first predetermined pulse attribute magnitude is different than said second predetermined pulse magnitude.    
   
   
       15 . The method of  claim 14 , wherein said output pulse further has at least a third predetermined pulse attribute magnitude, and said active discharge pulse has at least a forth predetermined pulse attribute magnitude, and wherein said third predetermined pulse attribute magnitude is different than said forth predetermined pulse magnitude.  
   
   
       16 . The method of  claim 15 , wherein said first and second predetermined pulse attribute magnitudes comprise a pulse duration, and wherein said third and forth predetermined pulse attribute magnitudes comprise a same one of a pulse voltage or a pulse current.  
   
   
       17 . The method of  claim 16 , wherein said pulse duration of said second predetermined pulse attribute magnitude is greater than said pulse duration of said first predetermined pulse attribute magnitude, and wherein said pulse voltage or pulse current of said fourth predetermined pulse attribute magnitude is less than said pulse voltage or pulse current of said third predetermined pulse attribute magnitude.  
   
   
       18 . The method of  claim 14 , further comprising: 
 controlling a fractional voltage converter to provide pulse voltages having said first predetermined pulse attribute magnitude and said second predetermined pulse attribute magnitude.    
   
   
       19 . The method of  claim 14 , wherein said providing said output pulse and said providing said active discharge pulse are provided by a stimulation system.  
   
   
       20 . The method of  claim 19 , further comprising: 
 providing therapy to a patient using said output pulse and said active discharge pulse.