Digital circuit for control of gradual turn-on of electrical tissue stimulators

• US 4,520,825 A
• Filed: 04/30/1982
• Issued: 06/04/1985
• Est. Priority Date: 04/30/1982
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Thompson, David L., Roline, Glenn M., Harrington, Richard J.
• Primary Examiner(s): Cohen, Lee S.
• Application Number:
  US06/373,679
• Time in Patent Office: 1,131 Days
• Field of Search: 128/419 PG, 128/419 PT, 128/421, 128/422, 128/423 R, 128/419 C, 128/419 E, 604/20
• US Class Current: 607/59
• CPC Class Codes: A61N 1/3603 Control systems

Abstract

A circuit for causing the gradual turn-on of electrical tissue stimulation in a digitally controlled stimulator is disclosed. A stimulation pulse counter and a pulses per step memory circuit are connected to a decoder to provide an amplitude incrementing signal after a presettable count of stimulation pulses. An amplitude counter receives the incrementing signal to increment the amplitude of the stimulation output pulse through a digital to analog converter circuit and to reset the pulse counter. A maximum amplitude memory circuit and decoder operate in conjunction with the amplitude counter to latch the counter when a preset pulse amplitude is obtained. At the end of a stimulation interval, the amplitude counter is reset and stimulation pulses begin at the minimum amplitude at the start of the next stimulation interval.

Claims

1. A remotely programmable circuit for control of gradual turn-on of electrical tissue stimulation comprising:

register means for holding digital signals corresponding to the amplitude of stimulation pulses to be delivered;

pulse generating means responsive to said digital signals for producing electrical tissue stimulation pulses;

means for altering said digital signals in response to successive occurrences of a predetermined number of pulses to cause discrete increases in the amplitude of stimulation pulses from the start of a stimulation interval until a predetermined maximum amplitude is obtained, said means for altering including first memory means for holding digital signals corresponding to said predetermined number, counter means for counting said pulses, and decoding circuit means responsive to said first memory means and said counter means for causing said discrete increases and for resetting said counter means when the count in said counter means corresponds to said predetermined number; and

means for receiving and decoding remotely generated programming signals and altering the contents of said first memory means to permit the rate of increase in the amplitude of stimulation pulses to be remotely programmed.

2. A circuit according to claim 1 wherein said means for altering includes second memory means for holding digital signals corresponding to said predetermined maximum amplitude and wherein said decoding circuit means is further responsive to said second memory means and said register means for preventing the digital signals in said register means from being altered when the signals in said register means correspond to said predetermined maximum amplitude.

3. A circuit according to claim 1 or 2 wherein said register means comprises a counter.

4. A remotely programmable circuit for control of gradual turn-on of electrical tissue stimulation pulses produced by a stimulation generator, comprising:

clocking means for producing periodic signals at a predetermined stimulation rate;

memory means for holding digital signals corresponding to a predetermined number of periodic signals;

counting means connected to said clocking means for maintaining digital signals corresponding to a count of said periodic signals;

decoding circuit means connected to said memory means and said counting means for producing a pulse amplitude incrementing signal when the digital signals in said memory means and said counting means correspond;

pulse amplitude stepping means responsive to said incrementing signal for causing said generator to increase stimulation pulse amplitude by a discrete amount and for resetting said counting means upon each increase;

maximum amplitude control means for preventing said decoding circuit means from increasing the amplitude of the stimulation pulses above a predetermined amplitude; and

means for receiving and decoding remotely generated programming signals and altering the contents of said memory means to permit the rate of increase in the amplitude of stimulation pulses to be remotely programmed.

5. A circuit according to claim 4 wherein said maximum amplitude control means includes amplitude memory means for holding digital signals corresponding to said predetermined amplitude and amplitude decoding circuit means connected to said amplitude memory means for preventing said amplitude stepping means from being incremented when said pulse amplitude corresponds to said predetermined amplitude.

6. A circuit according to claim 5 wherein said pulse amplitude stepping means comprises a counter.

7. A remotely programmable circuit for control of gradual turn-on of electrical tissue stimulation, comprising:

oscillator means for producing periodic signals at a predetermined stimulation rate;

first counting means connected to said oscillator means for counting said periodic signals;

first memory means for holding digital signals corresponding to a predetermined number of said periodic signals;

first decoding means connected to said first memory means and said counting means for producing a stepping signal and resetting said first counting means when the count in said first counting means corresponds to the digital signals held in said first memory means;

second counting means clocked by said stepping signal for producing amplitude controlling digital signals corresponding to the amplitude of stimulation pulses to be delivered;

pulse generating means responsive to said amplitude controlling signals for producing electrical tissue stimulation pulses;

second memory means for holding digital signals corresponding to a predetermined amplitude of said tissue stimulating pulses;

second decoding means connected to said second memory means and said second counting means for preventing the count in said second counting means from advancing when the count in said second counting means corresponds to the digital signals held in said second memory means; and

means for receiving and decoding remotely generated programming signals and altering the content of said first and second memory means to permit the rate of increase in the amplitude of stimulation pulses and the maximum stimulation pulse amplitude to be remotely programmed.