Patent ID: 8340758

Claim:
An apparatus for controlling electrical stimulation used for stimulating nerve fibers, comprising: an electrode array including an electrode set having a first electrode, a second electrode, a third electrode and a fourth electrode, each of which is separately powered and controlled by an independent power source; and an electrode controller for receiving input control signals and driving an electrode set in the electrode array so as to generate a composite stimulation signal in the electrode set; wherein the second and third electrodes are adjacent and are of a first power polarity for controlling a location of the composite stimulation signal, and the first and fourth electrodes are of a second power polarity which is inverse with respect to the first power polarity, so as to balance a total power polarity of the electrode set and focus on a stimulation region of the composite stimulation signal which is generated between the second and the third electrodes, and wherein the second and third electrodes of the first power polarity have a power setting designated as (−(1−A))P and (−A)P, respectively, while the first and fourth electrodes of the second power polarity have a power setting designated as (B)P and (1−B)P, respectively, where A and B are parameters ranging from 0 to 1, the location of the composite stimulation signal can be controlled by adjusting the parameters A and B, and P is a total power setting.