Active discharge of a coupling capacitor in an implantable medical device
First Claim
1. In an implantable medical device, including a therapy circuit, a coupling capacitor coupled to the therapy circuit, and an active discharge circuit for actively discharging the coupling capacitor after an electrical pulse has been passed through the coupling capacitor from the therapy circuit to animal tissue, the coupling capacitor having first and second electrodes, wherein the first electrode of the coupling capacitor is coupled to the therapy circuit and wherein the second electrode of the coupling capacitor may be coupled to animal tissue, the active discharge circuit including:
- a charge supply;
a charge transfer capacitor;
switching means for coupling the charge transfer capacitor between ground potential and the charge supply in response to the switching means assuming a first state, wherein charge is transferred between the charge transfer capacitor and the charge supply, and for coupling the charge transfer capacitor between ground potential and the first electrode of the coupling capacitor in response to the switching means assuming a second state, wherein charge is transferred between the charge transfer capacitor and the coupling capacitor so as to discharge the coupling capacitor; and
clock means for generating an oscillating clock signal and for causing the switching means to sequentially assume the first state and the second state, the clock signal being coupled to the switching means, whereby the switching means oscillates between the first state and the second state;
whereby the coupling capacitor is actively discharged in response to the oscillating of the first switching device between the first and second states.
1 Assignment
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Accused Products
Abstract
An active discharge circuit for use within an implantable medical device, such as a pacemaker, rapidly discharges a coupling capacitor connected between a therapy circuit and body tissue. The active discharge circuit has a switching device, a charge transfer capacitor, and a clock. The clock is coupled to a control input of the switching device and provides a clock signal thereto. In response to the clock signal, the switching device sequentially and repeatedly couples the charge transfer capacitor to a discharge voltage supply so that charge transfers therebetween, and then couples the charge transfer capacitor to the coupling capacitor so that charge transfers therebetween. As the switch oscillates in response to the clock signal, the coupling capacitor is actively discharged.
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Citations
24 Claims
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1. In an implantable medical device, including a therapy circuit, a coupling capacitor coupled to the therapy circuit, and an active discharge circuit for actively discharging the coupling capacitor after an electrical pulse has been passed through the coupling capacitor from the therapy circuit to animal tissue, the coupling capacitor having first and second electrodes, wherein the first electrode of the coupling capacitor is coupled to the therapy circuit and wherein the second electrode of the coupling capacitor may be coupled to animal tissue, the active discharge circuit including:
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a charge supply; a charge transfer capacitor; switching means for coupling the charge transfer capacitor between ground potential and the charge supply in response to the switching means assuming a first state, wherein charge is transferred between the charge transfer capacitor and the charge supply, and for coupling the charge transfer capacitor between ground potential and the first electrode of the coupling capacitor in response to the switching means assuming a second state, wherein charge is transferred between the charge transfer capacitor and the coupling capacitor so as to discharge the coupling capacitor; and clock means for generating an oscillating clock signal and for causing the switching means to sequentially assume the first state and the second state, the clock signal being coupled to the switching means, whereby the switching means oscillates between the first state and the second state; whereby the coupling capacitor is actively discharged in response to the oscillating of the first switching device between the first and second states. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. In an implantable medical device, a method for actively discharging a coupling capacitor after an electrical pulse has been passed through the coupling capacitor from a therapy circuit to an animal tissue, wherein a first electrode of the coupling capacitor is coupled to the therapy circuit within the implantable medical device and wherein a second electrode of the coupling capacitor is coupled to the animal tissue, the method including:
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(a) coupling a charge transfer capacitor to a discharge voltage supply so as to transfer charge between the charge transfer capacitor and the discharge voltage supply; (b) decoupling the charge transfer capacitor from the discharge voltage supply; and (c) coupling, the charge transfer capacitor to the first electrode of the coupling capacitor so as to transfer charge between the charge transfer capacitor and the coupling capacitor, wherein the coupling capacitor is at least partially discharged by the transfer of charge between the charge transfer capacitor and the coupling capacitor. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. An implantable medical device comprising:
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a therapy circuit for providing therapeutic stimulation pulses to body tissue; a coupling capacitor coupled between the therapy circuit and body tissue; and a discharge circuit comprising; a source of electrical charge; a transfer capacitor; and switching means for selectively electrically interconnecting the transfer capacitor between ground and one of said charge source and said coupling capacitor, whereby when connected to the charge source, the transfer capacitor is charged by the charge source and when connected to the coupling capacitor, the transfer capacitor causes charge to be transferred between the transfer capacitor and the coupling capacitor so as to discharge the coupling capacitor. - View Dependent Claims (24)
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Specification