NEUROSTIMULATION APPARATUS

1 . An output stage for an auditory neurostimulation electrode that is operable to effect a plurality of stimulation and discharge intervals, the output stage comprising:

a stimulation channel coupled to said electrode, wherein a stimulation current may flow therethrough during said stimulation intervals;

a discharge channel coupled to said electrode, wherein a discharge current may flow therethrough during said discharge intervals; and

a controller that is operable to selectively control the flow of current through said stimulation channel and said discharge channel during said stimulation and discharge intervals;

wherein one of said stimulation channel and said discharge channel couples said electrode to a voltage supply, and the other of said stimulation channel and said discharge channel couples said electrode to a reference potential node.

2 . An output stage as recited in claim 1 , wherein said controller is operable to control the timing of said stimulation and discharge intervals such that said stimulation and discharge intervals are successive.

3 . An output stage as recited in claim 1 , wherein the amount of charge transferred in said discharge intervals is greater than the amount of charge transferred in said stimulation intervals.

4 . An output stage as recited in claim 3 , wherein said stimulation current and said discharge current are dependent upon a corresponding physical characteristic of said stimulation channel and said discharge channel.

5 . An output stage as recited in claim 4 , wherein said stimulation channel and said discharge channel each includes a transistor, and wherein said physical characteristic includes a physical dimension of each transistor.

6 . An output stage as recited in claim 1 , wherein said discharge current is limited by the potential difference between said electrode and at least one of said reference potential node and the voltage of said voltage supply.

7 . An output stage as recited in claim 1 , wherein said controller is further operable to selectively adjust the magnitude of said stimulation and discharge currents.

8 . An output stage as recited in claim 1 , further comprising a charge recovery mechanism that is operable to recover accumulated charges on said electrode.

9 . An output stage as recited in claim 8 , wherein said charge recovery mechanism includes a resistor that is selectively interconnectable between said electrode and said reference potential node.

10 . An output stage as recited in claim 1 , wherein said controller includes at least one current mirror.

11 . An output stage as recited in claim 10 , wherein the amount of charge that flows through said stimulation channel and said discharge channel during said stimulation and discharge intervals is dependent upon a physical dimension of at least one component of said current mirror.

12 . An output stage as recited in claim 1 , wherein said output stage is interconnected with an electrode interface that is operable to selectively interconnect an output of said output stage to one or more of a plurality of auditory neurostimulation electrodes.

13 . An output stage as recited in claim 12 , wherein said electrode interface is operable to selectively interconnect said output of said output stage to a first and second set of said plurality of auditory neurostimulation electrodes to effect a plurality of successive stimulation and discharge intervals on said first and second sets of electrodes, wherein said first and second sets are not identical.

14 . A method for driving an electrode for auditory neurostimulation, the method comprising:

first transferring a stimulation current between an electrode and one of a voltage supply and a reference potential node; and

second transferring a discharge current between said electrode and the other of said voltage supply and said reference potential node.

15 . A method as recited in claim 13 , wherein the amount of charge transferred in said first transferring step is less than the amount of charge transferred in said second transferring step.

16 . A method as recited in claim 13 , further comprising:

limiting the amount of charge transferred in said second transferring step dependent upon the voltage potential on said electrode.

17 . A method as recited in claim 13 , further comprising:

selectively alternating between said first and second transferring steps to provide auditory neurostimulation to a patient.

18 . A method as recited in claim 13 , further comprising:

selectively varying the duration of each of said first and second transferring steps.

19 . A method as recited in claim 13 , further comprising:

selectively varying the amount of charge transferred in at least one of said first and second transferring steps.

20 . A method as recited in claim 13 , further comprising:

removing accumulated charges from said electrode.

21 . A method as recited in claim 13 , wherein the amount of charge transferred in the first and second transferring steps is regulated by a current mirror.

22 . A method as recited in claim 21 , wherein the amount of charge transferred in the first and second transferring steps is dependent upon a physical dimension of at least one component of said current mirror.