Title:
PROGRAMMABLE CURRENT OUTPUT STIMULUS STAGE FOR IMPLANTABLE DEVICE
Document Type and Number:
WIPO Patent Application WO2000000251
Kind Code:
A9
Abstract:
A programmable output current stage (200) for use within an implantable tissue or nerve stimulator, e.g., an implantable cochlear stimulator or spinal cord stimulator, includes parallel-connected P-FET current source sets (210) connected between a positive voltage rail (+V) and an electrode node (204), and parallel-connected N-FET current source sets (220) connected between the electrode node (204) and a negative voltage rail (-V). The N-FET current source sets (220) include n N-FET current sources (220a, 220b, 220c, 220d, ..., 220n), where n is an integer, and wherein each N-FET current source, when enabled, respectively sinks a current 2I from the electrode node (204) to the negative rail (-V), where I is a selectable fixed current. Similarly, the P-FET current source sets (210) include n P-FET current sources (210a, 210b, 210c, 210d,..., 210n), and wherein each P-FET current source, when enabled, respectively sources a current 2I from the positive voltage rail (+V) to the electrode node (204). An individual current pulse is formed by selecting an electrode pair, and enabling a desired combination of P-FET current sources so that a desired total current is sourced to one of the electrodes of the selected electrode pair, and at the same time enabling a corresponding combination of N-FET current sources so that the same total current is sunk from the other electrode of the selected electrode pair. Sequences of current pulses, e.g., biphasic or multiphasic stimulation pulse pairs, are formed by combining individual current pulses having the desired polarity and timing relationship. In one embodiment, the programmable amplitude of the current pulse is further enhanced through the addition of m P-FET and m N-FET current sources (212, 222) as part of the P-FET and N-FET current source sets, respectively, that source or sink a current I/2, when enabled, where m = 1, 2, 3, ..., m.
Inventors:
GORD JOHN C
Application Number:
PCT/US1999/014190
Publication Date:
October 05, 2000
Filing Date:
June 23, 1999
Export Citation:
Assignee:
ADVANCED BIONICS CORP (US)
International Classes:
A61N1/08; A61N1/32; A61N1/36; A61N1/372; A61N1/39; (IPC1-7): A61N1/08
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