System and method for independently operating multiple neurostimulation channels

1. A multi-channel neurostimulation system, comprising:

a plurality of electrical terminals configured for being respectively coupled to a plurality of electrodes;

stimulation output circuitry including electrical source circuitry of the same polarity configured for generating a plurality of pulsed electrical waveforms in a plurality of timing channels; and

control circuitry configured for instructing the stimulation output circuitry to serially couple the electrical source circuitry to different sets of the electrodes when pulses of the respective pulsed electrical waveforms do not temporally overlap each other, and for instructing the stimulation output circuitry to couple the electrical source circuitry to a union of the different electrode sets when pulses of the respective pulsed electrical waveforms temporally overlap each other.

2. The neurostimulation system of claim 1 ,

wherein the pulsed electrical waveforms are defined by a respective plurality of stimulation parameter sets;

wherein the control circuitry is configured for obtaining a digital representation of an electrode set from each of the stimulation parameter sets, combining the digital representations together to create a union of the digital representations, and outputting the digital representation union to the stimulation circuitry; and

wherein the stimulation output circuitry is configured for coupling the electrical source circuitry to the union of the different electrode sets in accordance with the digital representation union.

3. The neurostimulation system of claim 2 , wherein each of the digital representations comprises a digital representation of current amplitude values for the respective electrode set, and wherein the control circuitry is configured for instructing the stimulation output circuitry to supply electrical current from the electrical source circuitry to the different sets of the electrodes or the union of the different electrode sets in accordance with the current amplitude values.

4. The neurostimulation system of claim 1 , wherein the stimulation output circuitry includes at least one switch bank coupled between the electrical source circuitry and the electrical terminals.

5. The neurostimulation system of claim 1 , wherein the electrical source circuitry comprises current source circuitry.

6. The neurostimulation system of claim 5 , wherein the current source circuitry comprises a plurality of current branches, and wherein the control circuitry is configured for selecting a current magnitude for each electrode in the union of the different electrode sets by assigning one or more of the current branches to the respective electrode.

7. The neurostimulation system of claim 1 , wherein the control circuitry includes:

a plurality of registers configured for storing digital representations of the electrode sets;

a plurality of timers configuring for outputting phase enabling signals in accordance with a pulse duration and pulse frequency of the pulsed electrical waveforms;

a plurality of AND gates, each of which has an input coupled to an output of a respective one of the registers and an input coupled to an output of a respective one of the timers; and

an OR gate having inputs coupled to respective outputs of the AND gates, and an output coupled to an input of the stimulation output circuitry.

8. The neurostimulation system of claim 7 , wherein the phase enabling signal output by each of the timers is high when the pulse of the respective pulsed electrical waveform is active.

9. The neurostimulation system of claim 1 , wherein the pulsed electrical waveforms have different frequencies.

10. The neurostimulation system of claim 1 , further comprising the plurality of electrodes.

11. The neurostimulation system of claim 1 , further comprising a housing containing the plurality of electrical terminals, stimulation output circuitry, and control circuitry.

12. A multi-channel neurostimulation system, comprising:

a plurality of electrical terminals configured for being respectively coupled to a plurality of electrodes;

a plurality of registers configured for storing a respective plurality of digital representations of different sets of the electrodes;

a plurality of timers configuring for outputting phase enabling signals in accordance with a pulse duration and pulse frequency of a respective plurality of pulsed electrical waveforms;

a plurality of AND gates, each of which has an input coupled to an output of a respective one of the registers and an input coupled to an output of a respective one of the timers;

an OR gate having inputs coupled to respective outputs of the AND gates; and

stimulation output circuitry having an input coupled to an output of the OR gate, the stimulation output circuitry including electrical source circuitry of the same polarity programmable to selectively couple to the electrodes via the electrical terminals based on the output of the OR gate.

13. The neurostimulation system of claim 12 , wherein the timers are operated independently of each other.

14. The neurostimulation system of claim 12 , wherein the electrical source circuitry comprises current source circuitry.

15. The neurostimulation system of claim 14 , wherein each of the digital representations comprises a digital representation of current amplitude values for the respective electrode set, and the current source circuitry is programmable to supply current to the electrodes based on the output of the OR gate.

16. The neurostimulation system of claim 15 , wherein the current source circuitry comprises a plurality of current branches, the system further comprising a branch distribution circuit configured for assigning one or more of the current branches to each of the electrodes based on the output of the OR gate.

17. The neurostimulation system of claim 16 , wherein each of the current branches comprises:

a switch bank coupled to the electrodes; and

a decoder coupled to the respective switch bank, wherein the branch distribution circuit is configured for supplying a digital code to each of the decoders, the digital code defining one of the electrodes to be coupled to the electrical source circuitry via the respective switch bank.

18. The neurostimulation system of claim 12 , wherein the pulsed electrical waveforms have different frequencies.

19. The neurostimulation system of claim 12 , further comprising the plurality of electrodes.

20. The neurostimulation system of claim 12 , further comprising a housing containing the plurality of electrical terminals, the plurality of registers, the plurality of timers, the plurality of AND gates, the OR gate, and the stimulation output circuitry.