RFID tag dynamically adjusting clock frequency

摘要

An RFID tag is configured to adjust its current clock frequency to conserve tag power while receiving a reader signal and/or backscattering a signal. The tag may determine whether to adjust its current clock frequency based on one or more timing parameters, which may be determined from a reader command and/or from a signal to be backscattered. The counting rate and/or limit of a tag counter and/or the power supplied to a tag component may also be adjusted. The current tag clock frequency may be adjusted during the signal reception/backscattering process and optionally restored once the process is completed.

主权项

1. A method for a Radio Frequency Identification (RFID) tag to dynamically adjust a frequency of a clock oscillator, the method comprising:
receiving, from a reader, values for two or more of a TRcal, an RTcal, a DR, a Tari, and a BLF; calculating a first symbol duration based on the received values; comparing the calculated first symbol duration to a symbol decision threshold; determining, based on the comparison, whether the frequency can be reduced;
if so then:
adjusting a counting rate of a counter;reducing the frequency by adjusting at least one of a divide ratio, bias, resistance, capacitance, and inductance of the clock oscillator;calculating a second symbol duration based on the reduced frequency; andif necessary to meet error limits of a protocol, then adjusting at least one of the second symbol duration and the reduced frequency such that the second symbol duration meets the error limits; andif not then:
not adjusting the counting rate of the counter, andnot reducing the frequency.