APPARATUS FOR DELIVERING ELECTRICAL STIMULATION ENERGY TO BODY-IMPLANTED APPARATUS WITH SIGNAL-RECEIVING MEANS

• US 3,796,221 A
• Filed: 07/07/1971
• Issued: 03/12/1974
• Est. Priority Date: 07/07/1971
• Status: Expired due to Term

• Current Assignee: Norman R. Hagfors
• Original Assignee: Norman R. Hagfors
• Inventors: Hagfors, Norman R.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US05/160,368
• Time in Patent Office: 979 Days
• Field of Search: 128/419,421,422,2.1P
• US Class Current: 607/59
• CPC Class Codes: A61N 1/372 Arrangements in connection with the implantation of stimulators
• CPC Class Codes: A61N 1/3787 from an external energy source

Abstract

An apparatus for delivering electrical stimulation energy to body-implanted apparatus with signal-receiving means is described which is particularly useful in implanted devices, including nerve and muscle stimulators, artificial organs, and certain electro-mechanical devices such as implanted dispensers for the administration of fluids to the body system. The electrical portion of the system includes a transmitter and receiver, with the transmitter normally being disposed or worn externally of the body of the patient or user and being arranged to generate pulses of predetermined amplitude at radio frequencies. The receiver includes a pick-up, a receiver and an output electrode arrangement which is normally subcutaneously implanted within the body of the patient. Since variations in signal energy received by the receiver from its coupled transmitter may occur due to relative positioning of the transmitter-receiver pair, the receiver serves to regulate the amount of energy delivered to the output electrodes such that relatively uniform impulses are normally applied to the output electrodes. Thus, even though there may be variations in the energy coupled from the transmitter to the receiver, a uniform output occurs; the arrangement providing a means for coupling an electrical signal of variable magnitude to provide an output or stimulation signal of constant energy amplitude or magnitude to an implanted device.

Claims

1. Apparatus for applying electrical stimulation signals of a constant energy envelope to an object located within the human body comprising:

a. a transmitter of pulse modulated radio frequency signals;

b. a radio receiver network means adapted to be subcutaneously implanted in the body of a patient and responsive to said pulse modulated signals for producing a demodulated output signal across first and second junctions thereof;

c. a cource of reference potential connected between said first and second junctions;

d. a controllable impedance means having an input coupled to said first and second junctions, output terminals, and a control terminal connected to said source of reference potential for maintaining the voltage at said output terminal substantially constant over a range of variations of said demodulated output signals; and

e. stimulation electrodes adapted to be surgically implanted and electrically coupled to said output terminals.

2. Apparatus as in claim 1 wherein said controllable impedance means comprises a semiconductor current control meanS having input, output and control electrodes, said input electrode being connected to said first junction, said output electrode being connected through a resistor to said second junction, and said control electrode being coupled to said source of reference potential.

3. Apparatus as in claim 2 and further including magnetically actuatable means for varying said source of reference potential from a location outside of the body.