Stimulator apparatus

• US 4,719,922 A
• Filed: 03/03/1986
• Issued: 01/19/1988
• Est. Priority Date: 03/03/1986
• Status: Expired due to Fees

• Current Assignee: 147638 Canada Incorporated
• Original Assignee: 147638 Canada Incorporated
• Inventors: Schulze, Hans, Padjen, Ante L., MacDougall, Bruce
• Primary Examiner(s): Cohen, Lee S.
• Application Number:
  US06/835,285
• Time in Patent Office: 687 Days
• Field of Search: 128/420 R, 128/421, 128/422, 128/423 R, 128/908
• US Class Current: 607/62
• CPC Class Codes: A61N 1/0452 Specially adapted for transcutaneous muscle stimulation [TMS]
• CPC Class Codes: A61N 1/0456 Specially adapted for transcutaneous electrical nerve stimulation [TENS]
• CPC Class Codes: A61N 1/36034 specified by the stimulation parameters
• CPC Class Codes: Y10S 128/908 Patient protection from electric shock

Abstract

A stimulator apparatus for applying a low frequency pulse train, modulating a high frequency pulse train, to a patient includes electrodes for placement on the patient in the area of stimulation. A programmable microprocessor generates the pulse train and an electrode driver, to which the low frequency pulse train is fed, is connected to the electrodes. An electrode monitor is connected to an output of the electrode driver, and the output of the monitor is fed to an interrupt terminal of the microprocessor whereby to detect an unacceptable electrode connection. The apparatus also includes a display console including a display arrangement and a switch group. The electrode driver, in accordance with the invention, provides an adjustable constant current to the electrodes.

Claims

1. A stimulator apparatus for applying a low frequency pulse train, modulating a high frequency pulse train to produce a modulated pulse train, to a patient, comprising:

electrode means for placement on said patient in the area of stimulation;

programmable microprocessor means for generating said modulated high frequency pulse train;

electrode driver means comprising means for providing an adjustable constant current to said electrode means, said means for providing an adjustable constant current comprising a constant current source having an input terminal and an output terminal, means for driving said constant current source having at least one input terminal and an output terminal and means for adjusting the amplitude of said constant current source having an input terminal and an output terminal, said modulated pulse train being fed to the input terminal of said means for adjusting the amplitude, the output terminal of said means for adjusting the amplitude being fed to said at least one input terminal of said means for driving said constant current source, the output terminal of said means for driving said constant current source being fed to the input terminal of said constant current source, and the output terminal of said constant current source being fed to said electrode means;

electrode monitor means having input and output means, the input means of said electrode monitor means being connected to the output means of said electrode driver means, the output means of said electrode monitor means being connected to an input terminal of said microprocessor means to detect poor electrode connections; and

a display console enclosing said programmable microprocessor means, said electrode driver means and said electrode monitor means, and including a display arrangement and a switch group;

and wherein said means for driving said constant current source comprises a first operational amplifier having a second input terminal comprising an inverting input terminal, said at least one input terminal comprising a non-inverting input terminal;

said constant current source comprising a transistor, said input terminal of said transistor comprising a base electrode, said output terminal of said transistor comprising a collector electrode and further including an emitter electrode;

the output terminal of said first operational amplifier being connected to the base electrode of said transistor;

the collector electrode of said transistor being connected to said electrode means;

the emitter electrode of said transistor being connected to the inverting terminal of said first operational amplifier;

and wherein said electrode monitor means comprises a second operational amplifier having an inverting input terminal, a non-inverting input terminal and an output terminal, a third operational amplifier having an inverting input terminal, a non-inverting input terminal, and an output terminal, and a 2 to 1 multiplexer;

said electrode means being connected to the inverting input terminal of said second operational amplifier;

the inverting terminal of said third operational amplifier being connected to an output of said microprocessor means to receive said modulated pulse train;

the output terminals of said second and third operational amplifiers being connected to said 2 to 1 multiplexer.

2. An apparatus as defined in claim 1 and further including a power supply comprising batteries providing driving power to said programmable microprocessor means, said electrode driver means and said electrode monitor means;

low battery detector means connected to said power supply and a further interrupt terminal of said microprocessor means to detect a low battery.

3. An apparatus as defined in claim 2 and further including audible alarm means connected to an output of said programmable microprocessor means for giving an audible signal when a bad electrode connection or low battery is detected.

4. An apparatus as defined in claim 3 and further including means for setting a session time comprising selected ones of said switches of said switch group.

5. An apparatus as defined in claim 4 and including filter means between the output terminal of said first operational amplifier and the base electrode of said transistor to provide low pass filtering between said operational amplifier and said transistor.

6. An apparatus as defined in claim 1 and further including session timer means for setting the time of each session comprising selected ones of said switches of said switch group.

7. An apparatus as defined in claim 1 and further including trigger means applied to an interrupt terminal of said programmable microprocessor means to apply pulses to the patient one at a time.