Clock generating circuit for radio frequency identification (RFID) tag and calibrating method of clock generating circuit

Abstract

The invention discloses a clock generating circuit for a radio frequency identification (RFID) tag and the calibrating method of the clock generating circuit and relates to the technical field of RFID. The clock generating circuit provided by the invention comprises a numerical control tuned oscillator, a controller, a counter and a digital baseband processing circuit. A demodulation signal Rx output by tag radio frequency is input to the tag digital baseband processing circuit and the controller, and a power-on reset signal Rst output by a reset signal generating circuit arranged at the front end of the tag radio frequency is input to the controller, the counter and the tag digital baseband processing circuit. A calibration-enable signal Calib_en output by the tag digital baseband processing circuit is connected to the input ends of the controller and the counter. The count output Count of the counter is connected to the input end of the controller, and Rst_cnt output by the controller is connected to the input end of the counter. By using the clock generating circuit and the calibrating method thereof, the influences of an integrated circuit manufacturing process, an application environment and temperature on the bit rate precision, the code, the duty ratio and the like of the chip of the RFID tag can be avoided, the power consumption of the chip of the tag can be reduced, and the finished product rate of the chip can be increased.

Description

[0001] technical field [0002] The invention relates to the technical field of radio frequency identification (RFID), in particular to a local clock generating circuit of a radio frequency identification system tag chip and a calibration method thereof. Background technique [0003] Radio Frequency Identification (RFID) is a non-contact automatic identification technology that uses radio frequency signals and spatial coupling transmission characteristics to realize automatic identification of identified targets. RFID systems usually consist of card readers, radio frequency tags and data management systems. According to the different methods of obtaining energy, radio frequency tags can be divided into three types: active electronic tags, semi-active electronic tags and passive electronic tags. Active electronic tags and semi-active electronic tags have a long recognition distance, but because they require micro batteries, they are bulky and costly. Passive electronic tags...

AI Technical Summary

Problems solved by technology

First of all, the discreteness may cause the code rate size and code rate accuracy returned by the tag to fail to meet the protocol requirements, and may cause errors in the receiving and decoding of the tag, thereby reducing the yield of the chip

In addition, in order to prevent the above problems, the oscillation frequency must be increased. However, if the oscillator works at a higher frequency, its own power consumption and the power consumption of subsequent digital circuits will increase, which will lead to overall chip degradation. Increased power consumption, resulting in a decrease in the recognition distance performance index of the tag chip

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