Current generation architecture for an implantable stimulator device having coarse and fine current control

摘要

Disclosed herein is a current generation architecture for an implantable stimulator device such as an Implantable Pulse Generator (IPG). Current source and sink circuitry are both divided into coarse and fine portions, which respectively can provide a coarse and fine current resolution to a specified electrode on the IPG. The coarse portion is distributed across all of the electrodes and so can source or sink current to any of the electrodes. The coarse portion is divided into a plurality of stages, each of which is capable via an associated switch bank of sourcing or sinking a coarse amount of current to or from any one of the electrodes on the device. The fine portion of the current generation circuit preferably includes source and sink circuitry dedicated to each of the electrode on the device, which can comprise digital-to-analog current converters (DACs). The DACs also receives the above-noted reference current, which is amplified by the DACs in fine increments by appropriate selection of fine current control signals. When the coarse and fine current control circuitry are used in tandem, ample current with a fine current resolution can be achieved at any electrode and in a space- and power-efficient manner.