A kind of passive ultra-high frequency RFID label chip with temperature sensing function
Technical field
The present invention relates to field of radio frequency identification, in particular it relates to a kind of passive ultra-high frequency RFID label chip with temperature sensing function.
Background technology
RF identification (Radio Frequency Identification, be called for short RFID) technology is to utilize RF-wise to communicate to reach the identification of article at a distance, follow the trail of, position and the purpose such as management.The various fields, even military use such as REID controls to manage in industrial automation, business automation, transportation, false proof are with a wide range of applications, and have the most caused and have paid close attention to widely.
Along with the ripe decline with RFID label tag cost of RFID technique, progressively presenting some development trends with bigger actual application value, one of them is that RFID combines with temperature sensor.Temperature sensing being combined with RFID can be any other thermally sensitive article collecting temperature information in perishable foodstuffs, medicine and logistics, it is also possible to provide data timely for many medical diagnosis tests and program.And temperature-sensing system of based on RFID technique serves the most important application in logistics.As: Cold Chain Logistics (fresh food, wine etc.);The environmental sensitivity article monitoring such as vaccine, medicine;Valuable cargo in special warehouse, such as grain, the monitoring of potato class equitemperature;Construction material temperature monitoring;Integrate other technologies, such as vibrations, illumination and displacement transducer and realize the monitoring to related objective and large cold storage monitoring temperature etc.;Can realize early warning when temperature changes in transport, delivery process, and contribute to the confirmation of responsibility of quality accident.
The existing label possessing temperature sensing function typically has two kinds, and a kind of outside temperature-sensitive element of many employings realizes temperature sensing, and this label product on the one hand material cost is higher with packaging cost, and on the other hand small product size is bigger;Another kind of principle based on band-gap reference, using audion and resistance to realize temperature sensing, this temperature sensing circuit can be made on a piece of silicon chip with label chip, but the power consumption of chip is bigger, and the resistance of larger area to be used, thus add the cost of chip.
During realizing the present invention, inventor finds at least to exist in prior art that volume is big, power consumption big and the high defect of success.
Summary of the invention
It is an object of the invention to, for the problems referred to above, propose a kind of passive ultra-high frequency RFID label chip with temperature sensing function, to realize, volume is little, power consumption is little and the advantage of low cost.
For achieving the above object, the technical solution used in the present invention is: a kind of passive ultra-high frequency RFID label chip with temperature sensing function, including radio-frequency front-end, AFE (analog front end), digital baseband circuit and memorizer, and temperature sensor;Wherein:
Described digital baseband circuit, for the signal received decode and responding, control simultaneously the read-write operation to memorizer, temperature sensor dormancy with wake up up, and control temperature sensor and perform temperature sensing and operate;
Described memorizer, writes data for storing the goods attribute information of passive ultra-high frequency RFID label, the ID of passive ultra-high frequency RFID label, temperature data and user.
Further, described radio-frequency front-end, including the demodulator circuit being connected with described digital baseband circuit respectively and modulation circuit, and the rectification circuit being connected with described AFE (analog front end);Wherein:
Described demodulator circuit, is used for extracting envelope from the radiofrequency signal that the reader being used for reading passive ultra-high frequency RFID label information sends, sends digital baseband to and be decoded after process;
Described modulation circuit, for the passive ultra-high frequency RFID label data that digital baseband circuit returns is modulated radio frequency band, and is sent to reader by radio-frequency antenna;
Described rectification circuit, for the rf wave that reader is launched is converted into the DC energy of labeling task, and is sent to AFE (analog front end).
Further, described AFE (analog front end), including the mu balanced circuit being connected with described rectification circuit, and the reset circuit that is connected with described mu balanced circuit and digital baseband circuit respectively and clock circuit;Wherein:
Described mu balanced circuit, for the DC voltage that rectification circuit exports is converted into galvanic current pressure, the electricity consumption part for whole chip provides running voltage;
Described reset circuit, is used for producing power-on reset signal, after the supply voltage that passive ultra-high frequency RFID label powers on and mu balanced circuit provides is stable, is drawn high by reset level, makes digital baseband circuit node signal reset;
Described clock circuit, for producing the clock signal needed for working for digital baseband circuit.
Further, described clock circuit, specifically include agitator.
Further, described temperature sensor, gather front-end circuit and analog-digital converter including the temperature information being sequentially connected to described digital baseband circuit;Wherein:
Described temperature information gathers front-end circuit, for producing the ambient temperature information that the voltage being directly proportional to temperature represents current, also produces the temperature independent reference voltage reference voltage as analog digital conversion;
Described analog-digital converter, for being converted to digital signal by the voltage signal indicating temperature information.
Further, described temperature information gathers front-end circuit, including PMOS MP1~MP8, NMOS tube MN1~MN16;Wherein:
The source electrode of described PMOS MP1~MP8 all links together, and is connected to the supply voltage of temperature information collection front-end circuit, and this supply voltage is provided by the mu balanced circuit in AFE (analog front end);The grid of PMOS MP1~MP8 all links together, and is connected to the drain electrode of MP2;PMOS MP1~the drain electrode of MP7, be respectively connected to the drain electrode of NMOS tube MN1~MN7;
The grid of described NMOS tube MN1 is connected with drain electrode, and links together with the grid of NMOS tube MN2;The grid of NMOS tube MN8 is connected with drain electrode and links together with the grid of NMOS tube MN9;NMOS tube MN1 and the source electrode of NMOS tube MN2, be connected with the drain electrode of NMOS tube MN9 with NMOS tube MN8 respectively;The source electrode of NMOS tube MN9 is connected with the drain electrode of NMOS tube MN15, and NMOS tube MN3~the respective grid of MN7 are connected with their drain electrode, and grid with NMOS tube MN10~MN14 is connected respectively;NMOS tube MN3~the source electrode of MN7, the drain electrode with NMOS tube MN10~MN14 is connected respectively;The source electrode of NMOS tube MN11 is connected to the drain electrode of NMOS tube MN10, and the source electrode of NMOS tube MN12 is connected to the drain electrode of NMOS tube MN11 and is connected with the source electrode of NMOS tube MN16;Grid and the drain electrode of NMOS tube MN16 link together, and are connected with the drain electrode of NMOS tube MN8 and the grid of NMOS tube MN15, gather reference voltage V REF of front-end circuit output as temperature information;
The source electrode of described NMOS tube MN13 is connected with the drain electrode of NMOS tube MN12, and the source electrode of NMOS tube MN14 is connected with the drain electrode of NMOS tube MN12;The drain electrode of NMOS tube MN14, gathers, as temperature information, the voltage VPTAT that the temperature of front-end circuit output is directly proportional, and NMOS tube MN8, NMOS tube MN15, the source electrode of NMOS tube MN10 are connected to the ground.
Further, the current mirror that described PMOS MP1-MP7 is constituted, reference current is mirrored to other each branch roads;Described NMOS tube MN3-MN14 is operated in sub-threshold region, utilizes difference and the principle of PTAT of the gate source voltage of sub-threshold region metal-oxide-semiconductor, produces the voltage of one be directly proportional to temperature (PTAT), and this PTAT voltage expression formula is as follows:
Wherein, η is the sub-threshold slope factor, VTFor thermal voltage, K represents the breadth length ratio of NMOS tube.
Further, owing to the gate source voltage of described metal-oxide-semiconductor becomes negative linear relationship with temperature, by gate source voltage and a part of superposition of VPTAT voltage of NMOS tube MN16, by reasonably adjusting circuit parameter, the grid in NMOS tube MN16 produces a reference voltage keeping constant with temperature;The expression formula of reference voltage is as follows:
Further, described radio-frequency front-end, AFE (analog front end), digital baseband circuit, memorizer, and are integrated in on a piece of silicon chip based on identical integrated circuit technology with temperature sensor.
The passive ultra-high frequency RFID label chip with temperature sensing function of various embodiments of the present invention, owing to including the radio-frequency front-end, AFE (analog front end), digital baseband circuit and the memorizer that are sequentially connected with, and the temperature sensor being connected with digital baseband circuit;Temperature sensor can be realized based on CMOS integrated circuit technology, traditional electronic label chip is combined with temperature sensor, a piece of silicon chip realizes temperature sensing function and radio frequency recognition function;Such that it is able to overcome the defect that volume in prior art is big, power consumption big and success is high, to realize, volume is little, power consumption is little and the advantage of low cost.
Other features and advantages of the present invention will illustrate in the following description, and, partly become apparent from description, or understand by implementing the present invention.
Below by drawings and Examples, technical scheme is described in further detail.
Accompanying drawing explanation
Accompanying drawing is for providing a further understanding of the present invention, and constitutes a part for description, is used for together with embodiments of the present invention explaining the present invention, is not intended that limitation of the present invention.In the accompanying drawings:
Fig. 1 is the operation principle schematic diagram that the present invention has the passive ultra-high frequency RFID label chip of temperature sensing function;
Fig. 2 is that the present invention has the operation principle schematic diagram of temperature information collection front-end circuit in the passive ultra-high frequency RFID label chip of temperature sensing function.
Detailed description of the invention
Below in conjunction with accompanying drawing, the preferred embodiments of the present invention are illustrated, it will be appreciated that preferred embodiment described herein is merely to illustrate and explains the present invention, is not intended to limit the present invention.
According to embodiments of the present invention, as depicted in figs. 1 and 2, it is provided that a kind of passive ultra-high frequency RFID label chip with temperature sensing function.
See Fig. 1, the passive ultra-high frequency RFID label chip with temperature sensing function of the present embodiment, including radio-frequency front-end, AFE (analog front end), digital baseband circuit, memorizer and temperature sensor, (i.e. radio-frequency front-end, AFE (analog front end), digital baseband circuit, memorizer and the temperature sensor of all circuit modules, temperature sensor is connected with digital baseband circuit and AFE (analog front end) respectively) based on identical integrated circuit technology, can be made in on a piece of silicon chip;Radio-frequency front-end, AFE (analog front end), digital baseband circuit and memorizer are sequentially connected with, and temperature sensor is connected with digital baseband circuit.About being described as follows of radio-frequency front-end, AFE (analog front end), digital baseband circuit, memorizer and temperature sensor:
(1) radio-frequency front-end, is the interface circuit that communicates with read write line of label, and the radio-frequency front-end of label chip is made up of rectification circuit, demodulator circuit and modulation circuit.The rf wave that reader is launched is converted into the DC energy of labeling task by rectification circuit;Demodulator circuit extracts envelope from the radiofrequency signal that reader sends, and sends digital baseband circuit to and be decoded after process;The data that label returns are modulated radio frequency band by modulation circuit, and are sent to reader by antenna.
(2) AFE (analog front end), is made up of mu balanced circuit, clock circuit and reset circuit.The DC voltage of the less stable that rectification circuit is exported by mu balanced circuit is converted into galvanic current pressure, as the running voltage of whole other partial circuits of chip;Clock circuit is an agitator, produces the clock signal needed for working for digital baseband circuit;Reset circuit produces power-on reset signal, and when label powers on, after supply voltage is stable, reset level is drawn high, and digital baseband circuit node signal resets.
(3) the signal received is decoded and responds by digital baseband circuit, control simultaneously the read-write operation to memorizer, temperature sensor dormancy with wake up up, and control temperature sensor perform temperature sensing operation.
(4) memorizer storage goods attribute information, tag ID, temperature data and user write data etc..
(5) temperature sensor, gathers front-end circuit and analog-digital converter including temperature information.Temperature information gathers front-end circuit and produces the ambient temperature information that the voltage being directly proportional to temperature represents current, also produces the temperature independent reference voltage reference voltage as analog digital conversion;The voltage signal indicating temperature information is converted to digital signal by analog-digital converter.
Especially, seeing Fig. 2, temperature information gathers front-end circuit, including PMOS MP1~MP8, NMOS tube MN1~MN16.Wherein, the source electrode of PMOS MP1~MP8 all links together and is connected to temperature information and gathers the supply voltage of front-end circuit, and this supply voltage is provided by the mu balanced circuit in AFE (analog front end);nullThe grid of PMOS MP1~MP8 all links together and is connected to the drain electrode of MP2,The drain electrode of PMOS MP1~MP7 is respectively connected to the drain electrode of NMOS tube MN1~MN7,The grid of NMOS tube MN1 is connected with drain electrode and links together with the grid of NMOS tube MN2,The grid of NMOS tube MN8 is connected with drain electrode and links together with the grid of NMOS tube MN9,NMOS tube MN1 is connected with the drain electrode of NMOS tube MN9 with NMOS tube MN8 respectively with the source electrode of NMOS tube MN2,The source electrode of NMOS tube MN9 is connected with the drain electrode of NMOS tube MN15,NMOS tube MN3~the respective grid of MN7 are connected with their drain electrode,And grid with NMOS tube MN10~MN14 is connected respectively,The drain electrode with NMOS tube MN10~MN14 respectively of the source electrode of NMOS tube MN3~MN7 is connected,The source electrode of NMOS tube MN11 is connected to the drain electrode of NMOS tube MN10,The source electrode of NMOS tube MN12 is connected to the drain electrode of NMOS tube MN11 and is connected with the source electrode of NMOS tube MN16,The grid of NMOS tube MN16 links together with drain electrode and is connected with the drain electrode of NMOS tube MN8 and the grid of NMOS tube MN15 and gathers reference voltage V REF of front-end circuit output as temperature information,The source electrode of NMOS tube MN13 is connected with the drain electrode of NMOS tube MN12,The source electrode of NMOS tube MN14 is connected with the drain electrode of NMOS tube MN12,The drain electrode of NMOS tube MN14 gathers, as temperature information, the voltage VPTAT that the temperature of front-end circuit output is directly proportional,NMOS tube MN8、NMOS tube MN15、The source electrode of NMOS tube MN10 is connected to the ground.
Reference current is mirrored to other each branch roads by the current mirror that PMOS MP1-MP7 is constituted.NMOS tube MN3-MN14 is operated in sub-threshold region, utilizes difference and the principle of PTAT of the gate source voltage of sub-threshold region metal-oxide-semiconductor, produces the voltage of one be directly proportional to temperature (PTAT), and this PTAT voltage expression formula is as follows:
Wherein, η is the sub-threshold slope factor, VTFor thermal voltage, K represents the breadth length ratio of NMOS tube.
Owing to the gate source voltage of metal-oxide-semiconductor becomes negative linear relationship with temperature, by gate source voltage and a part of superposition of VPTAT voltage of NMOS tube MN16, by reasonably adjusting circuit parameter, the grid in NMOS tube MN16 produces a reference voltage keeping constant with temperature.The expression formula of reference voltage is as follows:
In the passive ultra-high frequency RFID label chip with temperature sensing function of above-described embodiment, the cmos device realization that temperature sensor employing is identical with label chip technique, the chip area of increase is the least;Meanwhile, the temperature characterisitic of cmos device based on sub-threshold region work, devise temperature information Acquisition Circuit, greatly reduce the power consumption of chip.
In sum, the passive ultra-high frequency RFID label chip with temperature sensing function of the various embodiments described above of the present invention, temperature sensor is realized based on CMOS integrated circuit technology, traditional electronic label chip is combined with temperature sensor, a piece of silicon chip realizes temperature sensing function and radio frequency recognition function;This has the passive ultra-high frequency RFID label chip of temperature sensing function, has advantage low in energy consumption, that area is little, packaging cost is low.
Last it is noted that the foregoing is only the preferred embodiments of the present invention, it is not limited to the present invention, although the present invention being described in detail with reference to previous embodiment, for a person skilled in the art, technical scheme described in foregoing embodiments still can be modified by it, or wherein portion of techniques feature is carried out equivalent.All within the spirit and principles in the present invention, any modification, equivalent substitution and improvement etc. made, should be included within the scope of the present invention.