Self-regulating transcutaneous energy transfer
First Claim
1. An implantable device for receiving electrical power from an external charger unit, the external charger unit producing an oscillating current in a primary coil at a driving frequency, the oscillating current producing an oscillating magnetic field proximate the external charger unit, the implantable device comprising:
- a secondary coil for receiving the oscillating magnetic field and producing an alternating current at the driving frequency, the amplitude of the alternating current depending in part on the driving frequency, on an amplitude of the oscillating current in the primary coil, and on the relative orientations of the primary and secondary coils;
a rectifier for receiving the alternating current from the secondary coil and producing a single-sided current;
a regulator for receiving the single-sided current from the rectifier and producing an essentially direct current at a regulated voltage;
a rechargeable battery charged by the essentially direct current; and
a control loop for temporarily short-circuiting both ends of the secondary coil to ground.
2 Assignments
0 Petitions
Accused Products
Abstract
A rechargeable battery system and method are disclosed, in which an implantable medical device (IMD) regulates its transfer of energy from a separate charger unit. For recharging, a charger unit is brought into proximity to the implanted device. An oscillating current is generated in a primary coil, located in the charger. By inductive coupling through an oscillating magnetic field, an alternating current is generated in a secondary coil, which is implanted in or near the implanted device. The alternating current then passes through a half-wave or full-wave rectifier to form a one-sided current, then passes through a regulator to form an essentially direct current, which is in turn directed to the rechargeable battery in the implanted device. The secondary coil has a controllable damped resonant frequency, which can be dynamically tuned away from the driving frequency of the primary coil by a variable resistor and/or by varying a duty cycle of a rapidly switched electrical element. If a control loop in the implant senses that more power is being received at the second coil than is actually being used to recharge the battery, the control loop temporarily changes the variable resistance. When this happens, the resonant frequency of the secondary coil is detuned slightly away from the driving frequency, so that less of the incoming power is absorbed by the secondary coil. Alternatively, the secondary coil may be temporarily short-circuited. With less or no excess power entering the circuitry of the implant, the problem of overheating is mitigated.
16 Citations
15 Claims
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1. An implantable device for receiving electrical power from an external charger unit, the external charger unit producing an oscillating current in a primary coil at a driving frequency, the oscillating current producing an oscillating magnetic field proximate the external charger unit, the implantable device comprising:
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a secondary coil for receiving the oscillating magnetic field and producing an alternating current at the driving frequency, the amplitude of the alternating current depending in part on the driving frequency, on an amplitude of the oscillating current in the primary coil, and on the relative orientations of the primary and secondary coils; a rectifier for receiving the alternating current from the secondary coil and producing a single-sided current; a regulator for receiving the single-sided current from the rectifier and producing an essentially direct current at a regulated voltage; a rechargeable battery charged by the essentially direct current; and a control loop for temporarily short-circuiting both ends of the secondary coil to ground. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A system for providing electrical power to an implantable device, comprising:
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an external charger unit, the external charger unit configured to produce an oscillating magnetic field proximate the external charger unit, the oscillating magnetic field having a constant oscillating magnetic field amplitude at a driving frequency; an implantable device including; a secondary coil configured to receive the oscillating magnetic field and produce an alternating current at the driving frequency; a rectifier configured to receive the alternating current from the secondary coil and produce a single-sided current; a regulator configured to receive the single-sided current from the rectifier and produce an essentially direct current at a regulated voltage; a rechargeable battery configured to be charged by the essentially direct current; and a control circuit configured to selectively short-circuit the secondary coil to ground. - View Dependent Claims (9, 10, 11, 12, 13)
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14. An implantable device for receiving electrical power from an external charger unit, the external charger unit producing an oscillating current in a primary coil at a driving frequency, the oscillating current producing an oscillating magnetic field proximate the external charger unit, the implantable device comprising:
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a secondary coil for receiving the oscillating magnetic field and producing an alternating current at the driving frequency; a rectifier for receiving the alternating current from the secondary coil and producing a single-sided current; a regulator for receiving the single-sided current from the rectifier and producing an essentially direct current at a regulated voltage; a rechargeable battery charged by the essentially direct current; and a control circuit configured to selectively short-circuit each end of the secondary coil to ground, the control circuit including at least two field-effect transistors, the control circuit configured such that each end of the secondary coil is switchable to ground via a corresponding one of the two field-effect transistors. - View Dependent Claims (15)
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Specification