Circuit and method for improving maximum working field intensity of ultrahigh frequency RFID tag chip

Abstract

The invention discloses a circuit and method for improving the maximum working field intensity of an ultrahigh frequency RFID tag chip, and the circuit comprises an antenna which is used for receivingand transmitting a wireless AC signal; a capacitor array which comprises n capacitor branches connected in parallel and used for selectively connecting a certain capacitor branch under the control ofthe control signal output by the hysteresis comparator array so as to change the impedance of the circuit; an alternating current-direct current converter which is used for converting the wireless signal received by the antenna into direct-current voltage VDD to be supplied to the tag chip to work; a voltage detection network which is used for detecting the direct current voltage VDD by detectingthe magnitude of the current flowing through the bleeder circuit to obtain n + 1 output voltages; and a hysteresis comparator array which is used for comparing the n + 1 voltage outputs of the voltage detection network so as to output n control signals to the capacitor array, so that the maximum working field intensity of the RFID tag chip can be improved.

Description

technical field [0001] The invention relates to a radio frequency identification (Radio Frequency Identification, RFID) technology, in particular to a circuit and a method for increasing the maximum working field strength of a UHF RFID tag chip. Background technique [0002] For a UHF RFID tag, when the tag chip is very close to the reader, the voltage of the circuit obtained through the rectifier will be far greater than the voltage that the device can withstand, which will cause the device to break down and fail. The most commonly used solution now is to design a bleeder circuit in the tag chip so that the output voltage of the rectifier can be effectively controlled within the voltage that the integrated device can withstand. However, the disadvantage of this method for ordinary UHF RFID chip tags is that it will cause chip heating and disturbance of the internal signal of the chip, which will affect the life of the device, the stability of the circuit and the reliability...

AI Technical Summary

Problems solved by technology

However, the disadvantage of this method for ordinary UHF RFID chip tags is that it will cause chip heating and disturbance of the internal signal of the chip, which will affect the life of the device, the stability of the circuit and the reliability of the memory data. For a temperature sensor As far as UHF RFID tags are concerned, in addition to the above problems, the measured temperature will also be inaccurate, so it is necessary to propose a technical means to solve the above problems

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