Biological tissue stimulator with adjustable high voltage power supply dependent upon load impedance

• US 4,917,093 A
• Filed: 06/12/1987
• Issued: 04/17/1990
• Est. Priority Date: 06/12/1987
• Status: Expired due to Term

• Current Assignee: Minnesota Mining and Manufacturing Co (3M Company)
• Original Assignee: Minnesota Mining and Manufacturing Co (3M Company)
• Inventors: Sondermann, William L., Dufresne, Joel R.
• Primary Examiner(s): Jaworski, Francis
• Assistant Examiner(s): Manuel, George
• Application Number:
  US07/061,695
• Time in Patent Office: 1,040 Days
• Field of Search: 128/421, 128/422, 128/419 R, 128/783, 128/784, 128/734, 128/419 D, 128/419 PG
• US Class Current: 607/62
• CPC Class Codes: A61N 1/36034 specified by the stimulation parameters
• CPC Class Codes: A61N 1/3782 producing a voltage above the power source level

Abstract

A biological tissue stimulator is disclosed having an adjustable high voltage power supply. The high voltage power supply is coupled to a battery producing a high voltage signal to be supplied to an output circuit for supplying an electrical stimulation signal of a predetermined current amplitude. An electrode is coupled to the electrical stimulation pulse and is adapted to be coupled to the biological tissue to deliver the electrical stimulation signal to the biological tissue. An adjustment mechanism is coupled to the output stage and to the adjustable high voltage power supply for comparing the amplitude of the high voltage signal to the amplitude of the voltage drop across the biological load and adjusting the amplitude of the high voltage signal dependent upon the result of that comparison. The adjustment mechanism adjusts the amplitude of the high voltage signal to minimize the difference in the amplitude between the high voltage signal and the voltage drop across the biological load thereby maximizing the energy efficiency of the biological tissue stimulator.

Claims

1. A biological tissue stimulator adapted to supply an electrical stimulation signal to a biological load, comprising:

a battery;

a high voltage power supply operatively coupled to said battery and producing a high voltage signal;

output means receiving said high voltage signal for supplying said electrical stimulation signal of a predetermined current amplitude;

electrode means receiving said electrical stimulation signal and adapted to be coupled to biological tissue for delivering said electrical stimulation signal so that said electrical stimulation signal may be applied to said biological tissue; and

adjustment means responsive to said output means and to said high voltage power supply for comparing the amplitude of said high voltage signal to the amplitude of the voltage drop across said electrode means during the application of said electrical stimulation signal to said biological tissue and adjusting the amplitude of said high voltage signal dependent upon the result of said comparing.

2. A biological tissue stimulator as in claim 1 wherein said adjustment means adjusts the amplitude of said high voltage signal to minimize the difference in amplitude between said high voltage signal and said voltage drop across said electrode means, whereby the efficiency of said biological stimulator is maximized.

3. A biological tissue stimulator as in claim 2 wherein said high voltage power supply is a switching-type power supply and with the amplitude of said high voltage signal being dependent upon control signals and wherein said adjustment means generates said control signals for said high voltage power supply.

4. A biological tissue stimulator adapted to supply an electrical stimulation signal to a biological load, comprising:

a battery;

a high voltage power supply operatively coupled to said battery and producing a high voltage signal whose amplitude is responsive to switching signals;

output means receiving said high voltage signal for supplying said electrical stimulation signal of a predetermined current amplitude;

electrode means receiving said electrical stimulation signal and adapted to be coupled to biological tissue for delivering said electrical stimulation signal so that said electrical stimulation signal may be applied to said biological tissue; and

adjustment means responsive to said output means and to said high voltage power supply for comparing the amplitude of said high voltage signal to the amplitude of the voltage drop across said electrical means and adjusting the amplitude of said high voltage signal dependent upon the result of said comparing to minimize the difference in amplitude between said high voltage signal and said voltage drop across said electrode means;

wherein said adjustment means comprises;

voltage gating means coupled to said output means for gating a slack voltage representing the voltage from said high voltage signal not dissipated across said electrode means;

a predetermined reference voltage;

comparison means responsive to said slack voltage and said predetermined reference voltage for comparing said slack voltage to said predetermined reference voltage for producing a comparison output indicative of the result of said comparing of said comparison means relative to a predetermined threshold; and

switching means responsive to said comparison output for supplying said switching signals so that said amplitude of said high voltage signal is properly adjusted relative to said predetermined threshold;

whereby the efficiency of said biological stimulator is maximized.

5. A biological tissue stimulator adapted to supply an electrical stimulation signal to a biological load, comprising:

a battery;

a high voltage power supply operatively coupled to said battery and producing a high voltage signal whose amplitude is responsive to control signals;

output means receiving said high voltage signal for supplying said electrical stimulation signal of a predetermined current amplitude;

electrode means receiving said electrical stimulation signal and adapted to be coupled to biological tissue for delivering said electrical stimulation signal so that said electrical stimulation signal may be applied to said biological tissue; and

adjustment means responsive to said output means and to said high voltage power supply for comparing the amplitude of said high voltage signal to the amplitude of the voltage drop across said electrode means and adjusting the amplitude of said high voltage signal dependent upon the result of said comparing to minimize the difference in amplitude between said high voltage signal and said voltage drop across said electrode means;

wherein said adjustment means comprises;

voltage gating means coupled to said output means for gating a slack voltage representing the voltage from said high voltage signal not dissipated across said biological load;

a first predetermined reference voltage;

a second predetermined reference voltage;

the value of said second predetermined reference voltage being greater than the value of said first predetermined reference voltage;

comparison means responsive to said slack voltage, to said first predetermined reference voltage and to said second predetermined reference voltage for comparing said slack voltage to said first predetermined reference voltage and producing a first comparison output indicative of such comparison, and for comparing said slack voltage to said second predetermined reference voltage and producing a second comparison output indicative of such comparison; and

switching means coupled to said high voltage power supply and receiving said first comparison output and said first comparison output from said comparison means for supplying said control signals lowering said high voltage signal when said second comparison signal indicates said slack voltage exceeds said second predetermined reference voltage, raising said high voltage signal when said first comparison signal indicates that said slack voltage does not exceed said first predetermined reference voltage;

whereby the efficiency of said biological stimulator is maximized.

6. A biological tissue stimulator as in claim 5 wherein said switching means supplies said control signals to said high voltage power supply maintaining said high voltage signal at a level at which the value of said slack voltage is kept between said first predetermined reference voltage and said second predetermined reference voltage.

7. A biological tissue stimulator as in claim 6 wherein said gating means supplies said control signals making said high voltage signal raise to its maximum allowable value when said first comparison output indicates that the value of said slack voltage is below said first predetermined reference voltage.

8. A biological tissue stimulator adapted to supply an electrical stimulation signal to a biological load, comprising:

a battery;

a high voltage power supply operatively coupled to said battery and producing a high voltage signal;

output means responsive to said high voltage signal for supplying said electrical stimulation signal of a predetermined current amplitude;

electrode means receiving said electrical stimulation pulse and adapted to be coupled to biological tissue for delivering said electrical stimulation signal so that said electrical stimulation signal may be applied to said biological tissue; and

adjustment means coupled to said output means and to said high voltage power supply for determining the impedance across said electrode means during the application of said electrical stimulation signal to said biological tissue and adjusting the amplitude of said high voltage and still have sufficient voltage amplitude to allow said output means to produce said electrical stimulation signal of said predetermined current amplitude;

whereby the efficiency of said biological tissue stimulator is maximized.

9. A biological tissue stimulator as in claim 8 wherein said high voltage power supply is a switching-type power supply and with the amplitude of said high voltage signal being dependent upon control signals and wherein said adjustment means generates said control signals for said high voltage power supply.

10. A biological tissue stimulator adapted to supply an electrical stimulation signal to a biological load, comprising:

a battery;

a high voltage power supply operatively coupled to said battery and producing a high voltage signal;

output means receiving said high voltage signal for supplying said electrical stimulation signal of a predetermined current amplitude;

electrode means receiving said electrical stimulation signal and adapted to be coupled to biological tissue for delivering said electrical stimulation signal so that said electrical stimulation signal may be applied to said biological tissue; and

adjustment means responsive to said output means and to said high voltage power supply for comparing the amplitude of said high voltage signal to the amplitude of the voltage drop across said electrode means and adjusting the amplitude of said high voltage signal dependent upon the result of said comparing;

wherein said adjustment means adjusts the amplitude of said high voltage signal to minimize the difference in amplitude between said high voltage signal and said voltage drop across said electrode means;

whereby the efficiency of said biological stimulator is maximized.

11. A biological tissue stimulator adapted to supply an electrical stimulation signal to a biological load, comprising:

a battery;

a high voltage power supply operatively coupled to said battery and producing a high voltage signal;

output means receiving said high voltage signal for supplying said electrical stimulation signal of a predetermined current amplitude;

electrode means receiving said electrical stimulation signal and adapted to be coupled to biological tissue for delivering said electrical stimulation signal so that said electrical stimulation signal may be applied to said biological tissue; and

adjustment means responsive to said output means and to said high voltage power supply for comparing the amplitude of said high voltage signal to the amplitude of the voltage drop across said electrical means and adjusting the amplitude of said high voltage signal dependent upon the result of said comparing;

wherein said high voltage power supply is a switching-type power supply and with the amplitude of said high voltage signal being dependent upon control signals and wherein said adjustment means generates said control signals for said high voltage power supply.