Wearable computing device having a charging system for a rechargeable battery

Patent metadata

Field	Value
Publication number	US-12451718-B2
Application number	US-202117557823-A
Country	US
Kind code	B2
Filing date	Dec 21, 2021
Priority date	Dec 21, 2021
Publication date	Oct 21, 2025
Grant date	Oct 21, 2025

Abstract

A wearable computing device is provided. The wearable computing device includes a housing and a rechargeable battery disposed within a cavity defined by the housing. The wearable computing device further includes a charging system disposed within the cavity. The charging system includes an alternating current (AC) generator configured to generate alternating current power. The charging system includes a rectifier circuit electrically coupled to a stator of the AC generator. The rectifier circuit is configured to convert AC power to direct current (DC) power. The charging system includes an energy storage device electrically coupled to the rectifier circuit such that the energy storage device is charged with the DC power. The charging system includes a solid state switch configured to selectively couple the energy storage device to the rechargeable battery to transfer charge from the energy storage device to the rechargeable battery.

First claim

What is claimed is:

1. A wearable computing device comprising:
a housing defining a cavity;
a rechargeable battery disposed within the cavity; and
a charging system disposed within the cavity, the charging system comprising:
an alternating current generator configured to generate alternating current power, the alternating current generator comprising a stator and a rotor, the stator comprising a plurality of poles arranged in an annular configuration about an interior circumferential portion of the housing, the rotor rotatable relative to the stator due to motion of a user wearing the wearable computing device;
a rectifier circuit electrically coupled to the stator of the alternating current generator, the rectifier circuit configured to convert the alternating current power to direct current power;
an energy storage device electrically coupled to the rectifier circuit such that the energy storage device is charged with the direct current power; and
a solid state switch coupled between the energy storage device and the rechargeable battery, the solid state switch configured to selectively couple the energy storage device to the rechargeable battery to transfer charge from the energy storage device to the rechargeable battery, wherein

each of the plurality of poles include a coil which is wrapped around a corresponding pole among the plurality of poles,
the rotor includes an arm configured to rotate about a center of the housing, and a magnet that is disposed at a distal end of the arm and which is spaced apart from the plurality of poles in a radial direction of the arm, the radial direction extending from the center of the housing toward the distal end of the arm, and
when a voltage across the energy storage device is less than a rated voltage of the rechargeable battery, the solid state switch is configured in a first state such that the energy storage device is decoupled from the rechargeable battery.

2. The wearable computing device of claim 1 , wherein the energy storage device comprises a supercapacitor.

3. The wearable computing device of claim 1 , wherein:
when a voltage across the energy storage device is greater than the rated voltage of the rechargeable battery, the solid state switch is configured in a second state such that the energy storage device is coupled to the rechargeable battery.

4. The wearable computing device of claim 1 , wherein the arm is rotatable about the center of the housing relative to the stator based on the motion of the user wearing the wearable computing device.

5. The wearable computing device of claim 1 , wherein the plurality of poles comprises an even number of poles.

6. The wearable computing device of claim 5 , wherein the plurality of poles comprise a total of twelve poles, and wherein each of the twelve poles are arranged in the annular configuration.

7. The wearable computing device of claim 1 , wherein
the rectifier circuit includes a half-wave rectifier or a full-wave rectifier.

8. The wearable computing device of claim 1 , wherein
the stator comprises a plurality of coils, each of the coils associated with a corresponding pole of the plurality of poles, and
the rectifier circuit is electrically coupled between a first terminal of a corresponding coil among the plurality of coils and a second terminal of the corresponding coil.

9. The wearable computing device of claim 8 , wherein the rectifier circuit is electrically coupled to each of the plurality of coils such that an alternating current associated with the alternating current power flows is unidirectional.

10. The wearable computing device of claim 1 , wherein the rated voltage is a voltage between about 1.2 volts to about 3 volts.

11. The wearable computing device of claim 1 , further comprising:
a current protection circuit coupled between the solid state switch and the rechargeable battery, the current protection circuit configured to limit a current associated with the charge being transferred from the energy storage device to the rechargeable battery.

12. The wearable computing device of claim 1 , wherein the solid state switch comprises a silicon controlled rectifier.

13. The wearable computing device of claim 1 , wherein the plurality of poles comprises an odd number of poles.

14. A method of charging a rechargeable battery of a wearable computing device, the method comprising:
generating, via an alternating current generator of a charging system for the wearable computing device, alternating current power from motion of the wearable computing device, wherein the alternating current generator comprises a stator and a rotor, the stator comprising a plurality of poles arranged in an annular configuration about an interior circumferential portion of a housing of the wearable computing device, each of the plurality of poles include a coil wrapped around a corresponding pole among the plurality of poles, and the rotor includes an arm configured to rotate about a center of the housing and a magnet that is disposed at a distal end of the arm and which is spaced apart from the plurality of poles in a radial direction of the arm, the radial direction extending from the center of the housing toward the distal end of the arm;
converting, via a rectifier circuit of the charging system, the alternating current power to direct current power;
charging an energy storage device of the charging system with the direct current power;
when a voltage across the energy storage device is more than a rated voltage of the rechargeable battery, configuring a solid state switch, disposed between the energy storage device and the rechargeable battery, in a first state, and transferring charge from the energy storage device to the rechargeable battery; and
when a voltage across the energy storage device is less than the rated voltage of the rechargeable battery, configuring the solid state switch in a second state to decouple the energy storage device from the rechargeable battery.

15. The method of claim 14 , wherein generating alternating current power from motion of the wearable computing device comprises:
generating a first alternating current voltage impulse on a first coil associated with a first pole of the plurality of poles of the stator of the alternating current generator due, at least in part, to a change in a first magnetic flux between the first pole and the rotor of the alternating current generator from rotational motion on the rotor due, at least in part, to the motion of the wearable computing device; and
generating a second alternating current voltage impulse on a second coil associated with a second pole of the plurality of poles due, at least in part, to a change in a second magnetic flux between the second pole and the rotor from the rotational motion of the rotor.

16. The method of claim 15 , wherein:
the change in the first magnetic flux comprises a decrease in the first magnetic flux; and
the change in the second magnetic flux comprises an increase in the second magnetic flux.

17. The method of claim 14 , wherein the rated voltage is a voltage between about 1.2 volts to about 3 volts.

18. The method of claim 14 , further comprising limiting, by a current protection circuit disposed between the solid state switch and the rechargeable battery, a current associated with the charge being transferred from the energy storage device to the rechargeable battery.

19. The method of claim 14 , wherein the energy storage device comprises a supercapacitor.

Assignees

• Google Llc

Inventors

• Itankar Piyush Tulsidas
• Goel Shantanu
• Agrawal Dheeraj Kumar
• Bharmal Mahmad Saifuddin

Classifications

• H02J7/70

  characterised by the mechanical construction · CPC title

• G06F1/163

  Wearable computers, e.g. on a belt · CPC title

• H02J7/345

  using capacitors as storage or buffering devices · CPC title

• G06F3/0488

  using a touch-screen or digitiser, e.g. input of commands through traced gestures · CPC title

• G04G17/04

  Mounting of electronic components · CPC title