Switched capacitor defibrillation circuit
First Claim
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1. An apparatus comprising:
- first and second switches adapted to be connected across a patient resistance and activatable when so connected to deliver a current to said patient in response to switching signals activating said first and second switches;
a plurality of capacitors providing said current through said first and second switches; and
capacitor switch means for selectively coupling said plurality of capacitors into parallel relation with one another to generate an approximate rectangular waveform for said current;
wherein said capacitor switch means and said plurality of capacitors cooperate to cause said waveform to rise to a first voltage level, decay for a selected time interval and thereafter experience a second rise and decay for a second selected time interval; and
wherein said plurality of capacitors includes a first and a second capacitor and said second rise and second delay are caused by said capacitor switch means switching of the second capacitor into parallel connection with the first capacitor.
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Abstract
A defibrillator circuit for generating a rectangular waveform across a patient from capacitively stored energy and employing a plurality of capacitors initially chargeable to a common voltage and thereafter sequentially switchable into parallel relation with one another so as to raise the voltage supplied to an H-bridge circuit from a point of decay back to said common voltage.
384 Citations
4 Claims
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1. An apparatus comprising:
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first and second switches adapted to be connected across a patient resistance and activatable when so connected to deliver a current to said patient in response to switching signals activating said first and second switches;
a plurality of capacitors providing said current through said first and second switches; and
capacitor switch means for selectively coupling said plurality of capacitors into parallel relation with one another to generate an approximate rectangular waveform for said current;
wherein said capacitor switch means and said plurality of capacitors cooperate to cause said waveform to rise to a first voltage level, decay for a selected time interval and thereafter experience a second rise and decay for a second selected time interval; and
wherein said plurality of capacitors includes a first and a second capacitor and said second rise and second delay are caused by said capacitor switch means switching of the second capacitor into parallel connection with the first capacitor. - View Dependent Claims (2)
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3. An apparatus comprising:
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first and second switches adapted to be connected across a patient resistance and activatable when so connected to deliver a current to said patient in response to switching signals activating said first and second switches;
a plurality of capacitors providing said current through said first and second switches; and
capacitor switch means for selectively coupling said plurality of capacitors into parallel relation with one another to generate an approximate rectangular waveform for said current;
wherein said capacitor switch means and said plurality of capacitors cooperate to cause said waveform to rise to a first voltage level, decay for a selected time interval and thereafter experience a second rise and decay for a second selected time interval;
wherein said plurality of capacitors includes at least four capacitors and said capacitor switch means includes a plurality of additional switches, said additional switches being constructed and arranged to selectively couple said capacitors into one of a plurality of parallel combinations; and
wherein said capacitors are selectively coupled in sequence to generate said waveform with four respective decays, said decays being proportional respectively to C1, C1+C2, C1+C2+C3, C1+C2+C3+C4 where C1, C2, C3, and C4 represent the respective values of said four capacitors. - View Dependent Claims (4)
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Specification