Patent ID: 7769462

Claim:
An implantable stimulator device, comprising: a plurality of electrode nodes implantable adjacent to tissue to be stimulated; programmable current source circuitry configured for sourcing a first one or more output currents respectively to a first one or more of the plurality of electrode nodes, wherein the current source circuitry comprises a plurality of adjustable positive current sources; programmable current sink circuitry configured for sinking a second one or more output currents respectively from a second one or more of the plurality of electrode nodes, wherein the current sink circuitry comprises a plurality of adjustable negative current sources; a programmable switch matrix; control circuitry configured for programming the current source circuitry and the current sink circuitry, such that the a total sum of the first one or more output currents equals a total sum of the second one or more output currents in each of one or more channels, and further configured for programming the switch matrix to selectively couple one or more of the positive current sources respectively to the first one or more of the electrode nodes, and for programming the switch matrix to selectively couple one or more of the negative current sources respectively to the second one or more of the electrode nodes.