Programmable waveform pulses for an implantable medical device

Abstract

Apparatus and method provide flexibility in generating a stimulation waveform to an electrode of an Implantable Neuro Stimulator (INS). The stimulation waveform is synthesized for each rate period interval. Each rate period interval is partitioned into time intervals, during which stimulation pulses, recharging, and time duration delays may be induced. With the embodiment of the invention, a second stimulation pulse, having different electrical characteristics than a first stimulation pulse, may be generated during the rate period interval. An embodiment utilizes apparatus comprising a waveform controller and a waveform generator that are controlled by the waveform controller. The waveform controller uses waveform parameters to instruct the waveform generator to form stimulation pulses. Any of the components may be adjusted or deleted in the generation of the stimulation waveform. The embodiment enables any of the associated waveform parameters to be updated at the waveform controller in order to alter the stimulation waveform.

1 . An apparatus for generating a neurological stimulation waveform, comprising:
 a waveform generator; and   a waveform controller coupled to the waveform generator, the waveform controller configured to control the waveform generator to generate a waveform for each of a plurality of rate period intervals, wherein each of the rate period intervals is partitioned such that the waveform includes:
 an interval; 
 a first stimulation pulse of a first polarity beginning immediately upon completion of the interval; 
 a time delay beginning immediately upon completion of the first stimulation pulse; and 
 a second stimulation pulse of a second polarity opposite the first polarity beginning immediately upon completion of the time delay, and 
   wherein the waveform controller is further configured to cause the waveform generator to provide a passive recharge beginning immediately upon completion of the second stimulation pulse.   
   
   
       2 . The apparatus of  claim 1 , wherein a duration of the time delay is adjustable. 
   
   
       3 . The apparatus of  claim 1 ,
 wherein the interval comprises a first time delay and a setup interval beginning immediately upon completion of the first time delay,   wherein the time delay beginning immediately upon completion of the first stimulation pulse comprises a second time delay,   wherein the waveform generator comprises a plurality of capacitors; and   wherein, during the setup interval, the waveform controller changes a configuration of the capacitors from a charge configuration to a stack configuration for generation of at least the first stimulation pulse.   
   
   
       4 . The apparatus of  claim 3 , wherein durations of the first and second time delays are adjustable. 
   
   
       5 . The apparatus of  claim 3 , wherein the waveform controller is configured to adjust at least one waveform parameter selected from the group consisting of the rate period interval, a duration of the first time delay, a duration of the second time delay, a width of the first stimulation pulse, a width of the second stimulation pulse, an amplitude of the first stimulation pulse, and an amplitude of the second stimulation pulse. 
   
   
       6 . The apparatus of  claim 5 , wherein a value of the waveform parameter for the rate period interval is different from a value of the waveform parameter for a subsequent rate period interval. 
   
   
       7 . The apparatus of  claim 5 ,
 wherein the apparatus comprises an implantable medical device and further comprises a telemetry module and a processor, and   wherein the processor is configured to receive a value of the waveform parameter from an external programming device via the telemetry module telemetry, and configure the waveform controller according to the received value.   
   
   
       8 . The apparatus of  claim 5 , further comprising:
 at least one register to store the at least one waveform parameter; and   a digital to analog converter configured to retrieve the at least one waveform parameter from the at least one register for generation of the first and second stimulation pulses.   
   
   
       9 . The apparatus of  claim 1 , wherein the first and second stimulation pulses comprise current or voltage pulses. 
   
   
       10 . The apparatus of  claim 1 , wherein each of the plurality of rate period intervals is less than 655 milliseconds. 
   
   
       11 . A method for generating a neurological stimulation waveform with an implantable medical device, the method comprising:
 generating a waveform for each of a plurality of rate period intervals, wherein each of the rate period intervals is partitioned such that the waveform includes:
 an interval, 
 a first stimulation pulse of a first polarity beginning immediately upon completion of the interval, 
 a time delay beginning immediately upon completion of the first stimulation pulse, and 
 a second stimulation pulse of a second polarity opposite the first polarity beginning immediately upon completion of the time delay; and 
   providing a passive recharge for each of the plurality of rate period intervals beginning immediately upon completion of the second stimulation pulse.   
   
   
       12 . The method of  claim 11 , wherein a duration of the time delay is adjustable. 
   
   
       13 . The method of  claim 11 ,
 wherein the interval comprises a first time delay and a setup interval beginning immediately upon completion of the first time delay,   wherein the time delay beginning immediately upon completion of the first stimulation pulse comprises a second time delay, and   the method further comprising, during the setup interval, changing a configuration of the capacitors from a charge configuration to a stack configuration for generation of at least the first stimulation pulse.   
   
   
       14 . The method of  claim 13 , wherein durations of the first and second time delays are adjustable. 
   
   
       15 . The method of  claim 11 , wherein the first and second stimulation pulses comprise current or voltage pulses. 
   
   
       16 . The method of  claim 11 , wherein each of the plurality of rate period intervals is less than 655 milliseconds. 
   
   
       17 . A computer-readable medium comprising instructions that cause a programmable processor of an implantable medical device to control generation of a waveform for each of a plurality of rate period intervals, wherein each of the rate period intervals is partitioned such that the waveform includes:
 an interval,   a first stimulation pulse of a first polarity beginning immediately upon completion of the interval,   a time delay beginning immediately upon completion of the first stimulation pulse, and   a second stimulation pulse of a second polarity opposite the first polarity beginning immediately upon completion of the time delay, and   wherein the instructions further cause the processor to control provision of a passive recharge for each of the plurality of rate period intervals beginning immediately upon completion of the second stimulation pulse.   
   
   
       18 . The medium of  claim 17 , wherein a duration of the time delay is adjustable. 
   
   
       19 . The medium of  claim 17 , wherein the first and second stimulation pulses comprise current or voltage pulses. 
   
   
       20 . The medium of  claim 17 , wherein each of the plurality of rate period intervals is less than 655 milliseconds.