Near field communications (NFC) device power harvesting and power supply selection
AssigneeBroadcom Innovision Limited
InventorPaul Butler
Life of this patent
Estimating the term…
Abstract
A near field RF communicator has an antenna circuit (102) to couple with the H field of an RF magnetic field and a power supply deriver (301) to derive a rectified auxiliary power supply from the received magnetic field. Rectification may be performed using an actively switched rectifier (502) having a passive mode of operation. A sub regulation system (506) is provided to regulate the auxiliary power supply to inhibit the possibility of temporally varying power requirements of the near field RF communicator or its host causing an apparent load modulation of a signal that is transmitted or received by the communicator.
Claims21
A communication device, comprising:
- an antenna circuit;
- a controller;
- and
- first and second power supplies, wherein the first power supply comprises:
- a rectifier configured to supply a rectified voltage derived from a magnetic field received by the antenna circuit;
- a charge storing element configured to store the rectified voltage;
- and
- a regulator configured to regulate the rectified voltage, and
- wherein the controller is further configured to control operation of the second power supply in accordance with a level of the magnetic field and to inhibit the first and second power supplies from operating at the same time.
A communication device, comprising:
- a rectifier configured to supply a rectified voltage derived from a magnetic field;
- a sensor configured to provide a sensor output that is a measure of an intensity of the magnetic field;
- a switch configured to provide the rectified voltage when in a first state or to not provide the rectified voltage when in a second state;
- and
- a controller configured to cause the switch to enter into the first state when the sensor output is greater than or equal to a threshold or to cause the switch to enter into the second state when the sensor output is less than the threshold.
A communication device, comprising:
- a first power supply;
- a second power supply;
- NFC functionality;
- and
- a controller configured to couple the first power supply to the NFC functionality when an intensity of a magnetic field is less than a threshold and to couple the second power supply to the NFC functionality when the intensity of the magnetic field is greater than or equal to the threshold.
Dependencies are inferred from the claim text.