Power converter apparatus for defibrillating cardiac pacemaker
First Claim
1. Power converter apparatus for receiving a relatively low dc input voltage and producing a relatively high dc output voltage, comprising:
- a transformer having a primary winding and a secondary winding;
a rectifier connected to the secondary winding of the transformer and including a capacitor that carries the dc output voltage;
a first pulse-width modulator for cyclically applying the input voltage to the primary winding of the transformer, each cyclic application being for a controllably-selected time duration, whereupon an electrical current is induced cyclically in the secondary winding of the transformer, to charge the capacitor of the rectifier; and
a feedback controller that measures one or more predetermined parameters of electrical signals present in the transformer and/or rectifier, to produce one or more binary feedback signals sent to the first pulse-width modulator, to controllably adjust the time duration of a subsequent application of the input voltage to the primary winding of the transformer.
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Accused Products
Abstract
A power converter apparatus adapted for use in a defibrillating cardiac pacemaker, to selectively provide a prescribed high voltage useful in treating a cardiac fibrillation. A pulse generator-cyclically applies a relatively low battery voltage Vs to a step-up transformer, to controllably charge a high-voltage capacitor. The time durations of the cyclic applications of the battery voltage Vs are controlled by digital feedback of several parameters, including peak transformer current, average transformer current., battery voltage Vs, and the voltage on the high-voltage capacitor. If any of the measured parameters is determined to be outside a predetermined limit, the pulsing of the transformer is incrementally modified. A smooth, efficient charging of the high-voltage capacitor thereby is provided.
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Citations
20 Claims
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1. Power converter apparatus for receiving a relatively low dc input voltage and producing a relatively high dc output voltage, comprising:
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a transformer having a primary winding and a secondary winding; a rectifier connected to the secondary winding of the transformer and including a capacitor that carries the dc output voltage; a first pulse-width modulator for cyclically applying the input voltage to the primary winding of the transformer, each cyclic application being for a controllably-selected time duration, whereupon an electrical current is induced cyclically in the secondary winding of the transformer, to charge the capacitor of the rectifier; and a feedback controller that measures one or more predetermined parameters of electrical signals present in the transformer and/or rectifier, to produce one or more binary feedback signals sent to the first pulse-width modulator, to controllably adjust the time duration of a subsequent application of the input voltage to the primary winding of the transformer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. Power converter apparatus for use in a defibrillating cardiac pacemaker, the apparatus receiving a relatively low dc input voltage and producing a relatively high dc output voltage, the power converter apparatus comprising:
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a transformer having a primary winding and a secondary winding; a rectifier connected to the secondary winding of the transformer and including a capacitor that carries the output voltage; a first pulse-width modulator for cyclically applying the input voltage to the primary winding of the transformer, at regular intervals of time, each cyclic application being for a controllably-selected time duration, whereupon an electrical current is induced cyclically in the secondary winding of the transformer, to charge the capacitor of the rectifier; and a feedback controller including first means for measuring the voltage on the capacitor of the rectifier and for comparing the measured voltage with a first predetermined threshold, to generate a first binary feedback signal according to the outcome of the comparison, second means for measuring a predetermined parameter of signals present in the transformer, to generate a second binary feedback signal, and combining means for combining the first and second binary feedback signals to produce a combined binary feedback signal coupled to the first pulse-width modulator, to controllably adjust the time duration of a subsequent application of the input voltage to the primary winding of the transformer. - View Dependent Claims (11, 12, 13)
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14. Power converter apparatus for receiving a relatively low dc input voltage and producing a relatively high dc output voltage, comprising:
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a transformer having a primary winding and a secondary winding; a rectifier connected to the secondary winding of the transformer and including a capacitor that carries the output voltage; a first pulse-width modulator for periodically applying the input voltage to the primary winding of the transformer, each periodic application being for a controllably-selected time duration, whereupon an electrical current is induced periodically in the secondary winding of the transformer, to charge the capacitor of the rectifier; and feedback control means operable in a first regime to condition the first pulse-width modulator to apply input power periodically to the primary winding of the transformer for time durations selected to provide a predetermined peak electrical current through the primary winding, and further operable in a second regime to condition the first pulse-width modulator to apply input power periodically to the primary winding for time durations selected to provide a predetermined average electrical current through the primary winding. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification