Abstract: Impedance matching between an RFID IC and an antenna may be tuned to increase the amount of power that the IC can extract from an RF wave incident on the antenna. A tuning circuit tunes the impedance matching by adjusting a variable impedance coupling the IC and the antenna and/or adjusting a bias of a rectifier in the IC. The tuning circuit may adjust the variable impedance and/or the rectifier bias based on predetermined or stored tuning settings. For example, the tuning circuit may retrieve stored tuning settings from a nonvolatile memory (NVM) configured to operate with limited functionality at low power.

Abstract: Data stored in nonvolatile memory on a Radio Frequency Identification (RFID) tag integrated circuit may have a “margin” associated with how strongly the data is written to the memory. Upon receiving a wireless margin read command, the RFID IC determines whether the margin for one of more data values stored in memory exceeds a margin threshold. The IC may determine the margin by applying bias voltages or currents to the memory cells storing the data values. If the determined margin does not exceed the margin threshold, the IC may respond with an error code.

Abstract: An RFID tag tuning circuit is capable of tuning the impedance matching between an RFID integrated circuit (IC) and an antenna on an RFID tag to increase the amount of power that the IC can extract from an incident RF wave. The tuning circuit tunes the impedance matching by adjusting a variable impedance coupling the antenna and the IC. Prior to tuning, the variable impedance is set using a voltage output from a tuning switch stage of an IC rectifier.

Abstract: A Radio Frequency Identification (RFID) tag integrated circuit (IC) includes a power rectifier component. The rectifier component includes a first current path formed by a first rectifying element, a second rectifying element, and a pump node coupled to the first and second rectifying elements. The first and second rectifying elements are coupled to a first phase of a radio frequency (RF) waveform while the pump node is coupled to a second phase of the RF waveform. The rectifier component also includes at least one biasing element coupled to the pump node and configured such that its terminal voltages vary with phases and amplitudes similar to that of the second phase of the RF waveform.