VCO driven flyback converter for implantable cardoverter/defibrillator
First Claim
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1. A medical device for the electrical termination of an arrhythmic condition of the heart, comprising:
- a battery;
a capacitor for storing voltage;
means for delivering voltage stored on said capacitor to cardiac tissues;
transformer means for providing charging current to said capacitor;
voltage sensing means coupled to said capacitor for sensing the voltage level stored on said capacitor and for generating a capacitor voltage signal indicative thereof;
voltage controlled oscillator means for coupling and uncoupling said transformer means from said battery, said oscillator means further comprising timing means defining on times during which said transformer means is coupled to said battery and off times during which said battery is uncoupled from said transformer means as a function of said capacitor voltage signal such that as said capacitor voltage signal indicates that the voltage level stored in said capacitor increases, the frequency of occurrence of said on times increases correspondingly and the durations of said off times simultaneously decrease.
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Abstract
A battery powered cardioverter or defibrillator employing output capacitors for delivery of cardioversion or defibrillation pulses. The capacitors are charged by means of a step-up transformer, coupled and uncoupled from the battery by means of a voltage controlled oscillator which varies its off and on times as a function of the voltage on the battery and the voltage stored on the output capacitor to allow for rapid charging of the capacitor even under conditions of battery depletion. The voltage controlled oscillator is constructed to provide a highly accurate timing signal with a low current drain.
55 Citations
14 Claims
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1. A medical device for the electrical termination of an arrhythmic condition of the heart, comprising:
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a battery; a capacitor for storing voltage; means for delivering voltage stored on said capacitor to cardiac tissues; transformer means for providing charging current to said capacitor; voltage sensing means coupled to said capacitor for sensing the voltage level stored on said capacitor and for generating a capacitor voltage signal indicative thereof; voltage controlled oscillator means for coupling and uncoupling said transformer means from said battery, said oscillator means further comprising timing means defining on times during which said transformer means is coupled to said battery and off times during which said battery is uncoupled from said transformer means as a function of said capacitor voltage signal such that as said capacitor voltage signal indicates that the voltage level stored in said capacitor increases, the frequency of occurrence of said on times increases correspondingly and the durations of said off times simultaneously decrease. - View Dependent Claims (2, 3, 10, 11, 12, 13, 14)
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4. A medical device for the electrical termination of an arrhythmic condition of the heart, comprising:
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a battery; a capacitor for storing voltage; means for delivering voltage stored on said capacitor to cardiac tissue; transformer means for providing charging current to said capacitor; first voltage sensing means for sensing the voltage stored on said capacitor and for generating a capacitor voltage signal indicative thereof; second voltage sensing means for sensing the voltage level of said battery and for generating a battery voltage signal indicative thereof; voltage controlled oscillator means for coupling and uncoupling said transformer means from said battery, said oscillator means comprising timing means defining on times during which said transformer means is coupled to said battery and off times during which said battery is uncoupled from said transformer means as function of both said battery voltage signal and said capacitor voltage signal. - View Dependent Claims (5, 6, 7, 8, 9)
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Specification