Patent ID: 9430729
Filing Date: 2016-08-30
CPC Classification: G06K

Claim Text:
1. An RFID apparatus, comprising: an input circuit having an input impedance used for receiving RF signals; an RF-signal converter configured and arranged to provide an apparatus-operating power signal in response to receiving the RF signals; an impedance circuit configured and arranged to provide and select impedance values in response to at least one select signal; a state-machine logic circuit configured and arranged to provide said at least one select signal, in response to the apparatus-operating power signal, for selecting the impedance values and therein permit the input impedance to be changed for tuning the apparatus; an attenuator connected between the RF-signal converter and the state-machine logic circuit; and a charge pump circuit coupled in parallel with the attenuator and the impedance circuit, wherein the charge pump circuit is configured to assist the RF-signal converter in providing an apparatus-operating power signal in response to receiving the RF signals during a read mode of operating the RFID apparatus and configured to be turned off during a write mode of operating the RFID apparatus, wherein the impedance circuit includes a selectable capacitance circuit having a plurality of nonvolatile MOS-device switches in which unit capacitance is changed by increasing or decreasing a threshold voltage of at least one MOS device from the plurality of nonvolatile MOS-device switches.