External charging device for charging an implantable medical device and methods of regulating duty cycle of an external charging device
First Claim
1. A stimulation system, comprising:
- (i) an implantable pulse generator (IPG) that comprises;
a first rechargeable battery for powering the IPG;
pulse generating circuitry;
a first coil for receiving RF power;
a rectifier coupled to the first coil; and
first control circuitry for controlling RF power conversion, wherein the first control circuitry clamps a first circuit node and a second circuit node, each connected to the first coil, to ground to limit further conversion of RF power by the rectifier when a power conversion voltage exceeds a predefined level;
and(ii) an external charging device for recharging the IPG, comprising;
a second rechargeable battery for powering the external charging device;
a second coil for radiating RF power;
drive circuitry for driving the second coil according to a duty cycle;
circuitry for generating a signal that is indicative of an amount of current flowing through the second coil; and
second control circuitry for controlling the drive circuitry, wherein the external charging device is operable to process the signal from the circuitry for generating to detect clamping of the first and second circuit nodes connected to the first coil to ground, the external charging device modifying the duty cycle in response to detection of the clamping of the first and second circuit nodes in the IPG to ground.
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Abstract
In one embodiment, an external charging device for recharging an implanted medical device, comprises: a battery for powering the external charging device; a coil for radiating RF power; drive circuitry for driving the coil according to a duty cycle; circuitry for generating a signal that is indicative of an amount of current flowing through the coil; and control circuitry for controlling the drive circuitry, wherein the control circuitry is operable to process the signal from the circuitry for generating to detect when a coil of the implantable medical device temporarily ceases absorbing RF power, the control circuitry modifying the duty cycle in response to detection of the coil of the implantable medical device temporarily ceasing absorbing RF power.
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Citations
12 Claims
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1. A stimulation system, comprising:
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(i) an implantable pulse generator (IPG) that comprises; a first rechargeable battery for powering the IPG; pulse generating circuitry; a first coil for receiving RF power; a rectifier coupled to the first coil; and first control circuitry for controlling RF power conversion, wherein the first control circuitry clamps a first circuit node and a second circuit node, each connected to the first coil, to ground to limit further conversion of RF power by the rectifier when a power conversion voltage exceeds a predefined level; and (ii) an external charging device for recharging the IPG, comprising; a second rechargeable battery for powering the external charging device; a second coil for radiating RF power; drive circuitry for driving the second coil according to a duty cycle; circuitry for generating a signal that is indicative of an amount of current flowing through the second coil; and second control circuitry for controlling the drive circuitry, wherein the external charging device is operable to process the signal from the circuitry for generating to detect clamping of the first and second circuit nodes connected to the first coil to ground, the external charging device modifying the duty cycle in response to detection of the clamping of the first and second circuit nodes in the IPG to ground. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of charging a medical device implanted with a human body using an external charging device, comprising:
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selecting a duty cycle on the external charging device; driving a first coil, by the external charging device, to radiate RF power according to the selected duty cycle; absorbing RF power by a second coil in the implanted medical device; converting the radiated RF power in the implanted medical device to electrical power; detecting, in the implanted medical device, that a RF conversion voltage has exceeded a defined limit; temporarily ceasing conversion of RF power to electrical power in the implanted medical device by clamping respective circuit nodes connected to the second coil to ground; detecting, by the external charging device, clamping of the respective circuit nodes to ground in the implanted medical device; and modifying the duty cycle for driving the first coil in response to the detecting of clamping of the respective circuit nodes to ground in the implanted medical device. - View Dependent Claims (8, 9, 10, 11, 12)
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Specification