Near field communications (NFC) device power harvesting and power supply selection

摘要

A near field RF communicator has an antenna circuit to couple with the H field of an RF magnetic field and a power supply deriver to derive a rectified auxiliary power supply from the received magnetic field. Rectification may be performed using an actively switched rectifier having a passive mode of operation. A sub regulation system 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.

主权项

1. A communication device, comprising:
a first power supply unit configured to derive a first power supply from a magnetic field, the first power supply unit comprising:
a first switch configured to couple the first power supply to near field communication (NFC) functionality or to decouple the first power supply from the NFC functionality; and a second switch configured to couple a second power supply to the NFC functionality or to decouple the second power supply from the NFC functionality, wherein the first switch and the second switch are further configured to operate in a complementary manner such that the first switch and the second switch are not configured to couple the first power supply and the second power supply, respectively, to the NFC functionality at the same time.