Energy Harvesting In RFID Systems

• US 20090174361A1
• Filed: 01/09/2008
• Published: 07/09/2009
• Est. Priority Date: 01/09/2008
• Status: Active Grant

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Wulff, Thomas, Duron, Mark, Calvarese, Russell, Sandler, Robert
• Granted Patent: US 8,035,335 B2
• Time in Patent Office: Days
• US Class Current: 320/101
• CPC Class Codes: H02J 5/00 Circuit arrangements for transfer of electric power between ac networks and dc networks H02J3/36 takes precedence
• CPC Class Codes: H02J 50/001 Energy harvesting or scavenging
• CPC Class Codes: H02J 50/15 using ultrasonic waves
• CPC Class Codes: H02J 50/20 using microwaves or radio frequency waves
• CPC Class Codes: H02J 50/30 using light, e.g. lasers
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters
• CPC Class Codes: H02M 7/219 in a bridge configuration
• CPC Class Codes: H04R 3/00 Circuits for transducers , loudspeakers or microphones

Abstract

Methods, systems, and apparatuses for providing power to devices that are part of RFID systems are described. Energy is harvested at portable/mobile devices, stored and conditioned to provide on-going power as needed for various circuits/components. The energy may be generated in a variety of ways, including using a vibratory energy harvesting device, a magnetic energy harvesting device, and an optical energy harvesting devices.

Claims

1. A method for providing power to a mobile device in an RFID system, comprising:

harvesting energy at the mobile device;

charging an energy storage device disposed on the mobile structure with the generated energy; and

powering one or more circuits of the mobile device with energy stored in the energy storage device.

2. The method of claim 1, wherein the harvesting comprises:

(a) generating the energy from vibration of the mobile structure during operation of the mobile structure.

3. The method of claim 2, wherein step (a) comprises:

generating the energy with a piezoelectric transducer mounted to the mobile structure.

4. The method of claim 1, wherein said generating comprises:

generating energy produced by relative movement of a magnet and a coil that are mounted to the mobile structure.

5. The method of claim 1, wherein said generating comprises:

converting light received at the mobile device into energy.

6. The method of claim 1, wherein said converting light comprises:

converting light received at the mobile device into energy using an optical-to-electrical transducer.

7. The method of claim 1, wherein said generating comprises:

obtaining power from a charge pump of an RFID tag associated with the mobile device.

8. The method of claim 1, wherein said generating comprises:

inducing a current in an antenna receiving a signal from an RFID interrogator; and

conditioning the current induced in the antenna for storage in the energy storage device.

9. The method of claim 1, further comprising:

conditioning power from the energy storage device.

10. The method of claim 9, wherein the conditioning comprises conditioning power with a buck boost regulator.

11. An arrangement for providing power to a mobile device in an RFID system, comprising:

an energy harvesting device associated with the mobile device;

an energy storage device disposed on the mobile device constructed and arranged to store power harvested by the energy harvesting device; and

a powering conditioning circuit for obtaining power from the energy storage device and providing power to one or more circuits of the mobile device.

12. An arrangement according to claim 11 further comprising a low voltage rectifier circuit, including:

first and second P-channel FETs; and

first and second N-channel FETs, the P and N-channel FETs being arranged in an H-bridge configuration.

13. An arrangement according to claim 11 wherein the energy harvesting device is a charge pump.

14. An arrangement according to claim 11 wherein the energy harvesting device is a piezo-electric device.

15. An arrangement according to claim 11 wherein the energy harvesting device is a magnetic device.

16. An arrangement according to claim 11 wherein the energy harvesting device is a photo-optic device.

17. An arrangement according to claim 11 wherein the energy storing device is a capacitor.

18. An arrangement according to claim 11 wherein the energy storing device is a battery.

19. A system for providing power to a portable device that is part of a radio frequency identification (RFID) system, comprising:

an energy storage device disposed on the portable device structure and coupled to the reader; and

an energy harvesting device disposed on the mobile structure that generates energy;

wherein the energy storage device stores the generated energy.

20. An arrangement according to claim 19 further comprising a low voltage rectifier circuit, including:

first and second P-channel FETs; and

first and second N-channel FETs, the P and N-channel FETs being arranged in an H-bridge configuration.

21. The system of claim 19, wherein the mobile structure is a headset.

22. The system of claim 19, wherein said energy harvesting device comprises:

a vibratory energy harvesting device that generates the energy from vibration of the mobile structure during operation of the mobile structure.

23. The system of claim 19, wherein said vibratory energy harvesting device comprises:

a piezoelectric transducer.

24. The system of claim 19, further comprising:

a moment arm that mounts the piezoelectric transducer; and

a capacitor coupled to the energy storage device;

wherein vibration of the arm causes the arm to deflect the piezoelectric transducer;

wherein the piezoelectric transducer generates a current due to the deflection, and

wherein the current charges the capacitor.

25. The system of claim 19, wherein said energy harvesting device comprises:

a magnetic induction energy harvesting device.

26. The system of claim 25, wherein said magnetic energy harvesting device comprises:

a magnet; and

a coil;

wherein the energy is generated by movement of the magnet through the coil field.

27. The system of claim 19, wherein said energy harvesting device comprises:

an photo-optical-to-electrical transducer that converts light received at the mobile structure into energy.

28. A low voltage rectifier circuit, comprising:

first and second P-channel FETs; and

first and second N-channel FETs, the P and N-channel FETs being arranged in an H-bridge configuration.