Output limited electrical stimulator for biological tissue

• US 4,690,145 A
• Filed: 06/17/1985
• Issued: 09/01/1987
• Est. Priority Date: 06/17/1985
• Status: Expired due to Fees

• Current Assignee: 3M Company
• Original Assignee: 3M Company
• Inventors: Dufresne, Joel R., ReMine, Walter J., King-Smith, Eric A.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US06/745,084
• Time in Patent Office: 806 Days
• Field of Search: 128/421, 128/422, 128/423
• US Class Current: 607/63
• CPC Class Codes: A61N 1/36021 for treatment of pain

Abstract

An output limited electrical stimulator for biological tissue. Stimulus parameters, which can be modulated, are used to specify an electrical stimulus signal. A calculation element calculates the electrical charge which would be generated by an electrical stimulus signal defined by the modulated stimulus parameters. A limit element compares the calculated electrical charge against a predetermined standard and adjusts at least one of the stimulus parameters. An electrical stimulus signal is then generated using the adjusted stimulus parameters assuring that the electrical stimulus signal generated will have an electrical charge of not more than the predetermined standard.

Claims

1. An electrical stimulator for biological tissus having output limits, comprising:

storage means for storing a plurality of sets of stimulus parameters designed to specify an electrical stimulus signal comprising a plurality of pulses each having a pulse amplitude and a pulse duration;

calculation means operatively coupled to said storage means for calculating the electrical charge which would be generated by each of said plurality of pulses contained in said electrical stimulus signal from said plurality of sets of stimulus parameters;

limit means having a stored predetermined standard for the maximum electrical charge to be delivered by each of said plurality of pulses, said limit means being operatively coupled to said calculation means for comparing said calculated electrical charge of said electrical stimulus pulse with a predetemined standard and adjusting at least one of said plurality of sets of stimulus parameters so that said electrical charge of said electrical stimulus signal would not exceed said predetermined standard;

generation means operatively coupled to said storage means, to said calculation means and to said limit means for taking at least one of said sets of stimulus parameteres as adjusted by said limit means and generating said electrical stimulus signal as designated by said and of said plurality of sets of stimulus parameters as adjusted.

2. An electrical stimulator as in claim 1 wherein said stimulus parameters include pulse amplitude and pulse duration and wherein said limit means adjusts said at least one of said plurality of sets of stimulus parameters by adjusting said pulse amplitude.

3. An electrical stimulator as in claim 1 wherein calculation means calculates said electrical change whenever a charge in the value of said plurality of sets of stimulus parameters occurs.