CN103699927A - Passive ultrahigh frequency RFID (radio frequency identification) label chip with temperature sensing function - Google Patents

本发明公开了一种具有温度感知功能的无源超高频RFID标签芯片，包括射频前端、模拟前端、数字基带电路和存储器温度传感器。本发明所述具有温度感知功能的无源超高频RFID标签芯片，可以克服现有技术中体积大、功耗大和成功高等缺陷，以实现体积小、功耗小和成本低的优点。

The invention discloses a passive ultra-high frequency RFID tag chip with temperature sensing function, which comprises a radio frequency front end, an analog front end, a digital baseband circuit and a memory temperature sensor. The passive UHF RFID tag chip with temperature sensing function of the present invention can overcome the defects of large size, high power consumption and high success in the prior art, so as to realize the advantages of small size, low power consumption and low cost.

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, particularly, relate to a kind of passive ultra-high frequency RFID label chip with temperature sensing function.

Background technology

Radio-frequency (RF) identification (Radio Frequency Identification is called for short RFID) technology is to utilize RF-wise to communicate by letter to reach the objects such as identification, tracking, location and management of article at a distance.REID is in industrial automation, business automation, and communications and transportation control and management, the various fields such as false proof, even military use is with a wide range of applications, and has caused at present widely and has paid close attention to.

Decline along with RFID technology maturation and RFID label cost, progressively presents the development trend that some have larger actual application value, and one of them is that RFID combines with temperature sensor.It can be any other thermally sensitive article collecting temperature information in perishable foodstuffs, medicine and logistics that temperature sensing and RFID are combined, and also can provide data timely for many medical diagnostic tests and program.And the temperature-sensing system based on RFID technology has played more and more important application in logistics.As: Cold Chain Logistics (FF, grape wine etc.); The environmental sensitivity such as vaccine, medicine article monitoring; Valuable cargo in special warehouse, as grain, the monitoring of potato class equitemperature; Building materials temperature monitoring; Integrate other technologies, such as vibrations, illumination and displacement transducer are realized the monitoring of related objective and large cold storage monitoring temperature etc.; Can realize early warning when temperature changes to transportation, in delivery process, and contribute to the confirmation of responsibility of quality accident.

The existing label that possesses temperature sensing function generally has two kinds, and a kind of external heat photosensitive elements that adopt are realized temperature sensing more, and this label product one side material cost and packaging cost are higher, and small product size is larger on the other hand; The another kind of principle based on band-gap reference, adopt triode and resistance to realize temperature sensing, this temperature sensing circuit can be made on a slice silicon chip with label chip, but the power consumption of chip is larger, and will use larger area resistance, thereby increased the cost of chip.

In realizing process of the present invention, inventor finds at least to exist in prior art that volume is large, power consumption large and the high defect of success.

Summary of the invention

The object of the invention is to, for the problems referred to above, propose a kind of passive ultra-high frequency RFID label chip with temperature sensing function, to realize the advantage that volume is little, power consumption is little and cost is low.

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, comprise radio-frequency front-end, AFE (analog front end), digital baseband circuit and storer, and temperature sensor; Wherein:

Described digital baseband circuit, for decoding to the received signal and responding, the dormancy of simultaneously controlling read-write operation to storer, temperature sensor with wake up, and control temperature sensor and carry out temperature sensing operation;

Described storer, 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's data writing.

Further, described radio-frequency front-end, comprises the demodulator circuit and the modulation circuit that are connected with described digital baseband circuit respectively, and the rectification circuit being connected with described AFE (analog front end); Wherein:

Described demodulator circuit, for from extracting envelope for reading the radiofrequency signal that the reader of passive ultra-high frequency RFID label information sends, sends digital baseband to and decodes after processing;

Described modulation circuit, is modulated to radio frequency band for the passive ultra-high frequency RFID label data that digital baseband circuit is returned, and sends to reader by radio-frequency antenna;

Described rectification circuit, for the rf wave of reader transmitting is converted into the DC energy of label work, and sends to AFE (analog front end).

Further, described AFE (analog front end), comprises the mu balanced circuit being connected with described rectification circuit, and the reset circuit and the clock circuit that are connected with digital baseband circuit with described mu balanced circuit respectively; Wherein:

Described mu balanced circuit, presses for the DC voltage of rectification circuit output is converted into galvanic current, for the electricity consumption of whole chip partly provides operating voltage;

Described reset circuit, for generation of power-on reset signal, after the supply voltage that passive ultra-high frequency RFID label powers on and mu balanced circuit provides is stablized, draws high reset level, and digital baseband circuit node signal is resetted;

Described clock circuit, for generation of supplying the required clock signal of digital baseband circuit work.

Further, described clock circuit, specifically comprises oscillator.

Further, described temperature sensor, comprises that the temperature information that is connected to successively described digital baseband circuit gathers front-end circuit and analog to digital converter; Wherein:

Described temperature information gathers front-end circuit, for generation of the voltage being directly proportional to temperature, represents current ambient temperature information, also produces a temperature independent reference voltage as analog-to-digital reference voltage;

Described analog to digital converter, for being converted to digital signal by the voltage signal that indicates temperature information.

Further, described temperature information gathers front-end circuit, comprises PMOS pipe MP1～MP8, and NMOS manages MN1～MN16; Wherein:

The source electrode of described PMOS pipe MP1～MP8 all links together, and is connected to the supply voltage that temperature information gathers front-end circuit, and the mu balanced circuit of this supply voltage in AFE (analog front end) provides; The grid of PMOS pipe MP1～MP8 all links together, and is connected to the drain electrode of MP2; The drain electrode of PMOS pipe MP1～MP7, is connected to respectively the drain electrode of NMOS pipe MN1～MN7;

The grid of described NMOS pipe MN1 is connected with drain electrode, and links together with the grid of NMOS pipe MN2; The grid of NMOS pipe MN8 is connected with drain electrode and links together with the grid of NMOS pipe MN9; The source electrode of NMOS pipe MN1 and NMOS pipe MN2, is connected with the drain electrode of NMOS pipe MN9 with NMOS pipe MN8 respectively; The source electrode of NMOS pipe MN9 is connected with the drain electrode of NMOS pipe MN15, and grid separately of NMOS pipe MN3～MN7 and their drain electrode are connected, and the grid of managing MN10～MN14 with NMOS is respectively connected; The source electrode of NMOS pipe MN3～MN7, is connected with the drain electrode of NMOS pipe MN10～MN14 respectively; The source electrode of NMOS pipe MN11 is connected to the drain electrode of NMOS pipe MN10, and the source electrode of NMOS pipe MN12 is connected to the drain electrode of NMOS pipe MN11 and is connected with the source electrode of NMOS pipe MN16; Grid and the drain electrode of NMOS pipe MN16 link together, and are connected with the grid of NMOS pipe MN15 with the drain electrode of NMOS pipe MN8, gather the reference voltage V REF of front-end circuit output as temperature information;

The source electrode of described NMOS pipe MN13 is connected with the drain electrode of NMOS pipe MN12, and the source electrode of NMOS pipe MN14 is connected with the drain electrode of NMOS pipe MN12; The drain electrode of NMOS pipe MN14, the voltage VPTAT that the temperature of exporting as temperature information collection front-end circuit is directly proportional, the source electrode of NMOS pipe MN8, NMOS pipe MN15, NMOS pipe MN10 is connected to ground.

Further, the current mirror that described PMOS pipe MP1-MP7 forms, is mirrored to other each branch roads by reference current; Described NMOS pipe MN3-MN14 is operated in sub-threshold region, and the principle of utilizing the difference of the gate source voltage of sub-threshold region metal-oxide-semiconductor to be directly proportional to absolute temperature produces the voltage of one be directly proportional to temperature (PTAT), and this PTAT voltage expression formula is as follows:

V PTAT = V gs 10 - V gs 3 + V gs 11 - V gs 4 + V gs 12 - V gs 5 + V gs 13 - V gs 6 + V gs 14 - V gs 7 = η V T ln ( K 3 / K 10 ) + η V T ln ( K 4 / K 11 ) + η V T ln ( K 5 / K 12 ) + η V T ln ( K 6 / K 13 ) + η V T ln ( K 7 / K 14 ) = η V T ln K 3 K 4 K 5 K 6 K 7 K 10 K 11 K 12 K 13 K 14 ;

Wherein, η is the sub-threshold slope factor, V _tfor thermal voltage, K represents the breadth length ratio of NMOS pipe.

Further, because the gate source voltage of described metal-oxide-semiconductor becomes negative linear relationship with temperature, NMOS is managed to the stack of the gate source voltage of MN16 and a part for VPTAT voltage, by Circuit tuning parameter reasonably, at the grid of NMOS pipe MN16, produce one and keep constant reference voltage with temperature; The expression formula of reference voltage is as follows:

V REF = V gs 16 + V gs 10 - V gs 3 + V gs 11 - V gs 4 = 2 I d μ C ox k + V th + η V T ln K 3 K 4 K 10 K 11 .

Further, described radio-frequency front-end, AFE (analog front end), digital baseband circuit, storer and temperature sensor) integrated circuit technology based on identical, and be integrated on same a slice silicon chip.

The passive ultra-high frequency RFID label chip with temperature sensing function of various embodiments of the present invention, owing to comprising radio-frequency front-end, AFE (analog front end), digital baseband circuit and the storer connecting successively, and the temperature sensor being connected with digital baseband circuit; Can realize temperature sensor based on CMOS integrated circuit technology, traditional electronic label chip and temperature sensor are combined, on a slice silicon chip, realize temperature sensing function and radio frequency recognition function; Thereby can overcome the defect that in prior art, volume is large, power consumption large and success is high, to realize the advantage that volume is little, power consumption is little and cost is low.

Other features and advantages of the present invention will be set forth in the following description, and, partly from instructions, become apparent, or understand by implementing the present invention.

Below by drawings and Examples, technical scheme of the present invention is described in further detail.

Accompanying drawing explanation

Accompanying drawing is used to provide a further understanding of the present invention, and forms a part for instructions, for explaining the present invention, is not construed as limiting the invention together with embodiments of the present invention.In the accompanying drawings:

Fig. 1 is the principle of work 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 principle of work schematic diagram that temperature information in the passive ultra-high frequency RFID label chip of temperature sensing function gathers front-end circuit.

Embodiment

Below in conjunction with accompanying drawing, the preferred embodiments of the present invention are described, should be appreciated that preferred embodiment described herein, only for description and interpretation the present invention, is not intended to limit the present invention.

According to the embodiment of the present invention, as depicted in figs. 1 and 2, provide a kind of passive ultra-high frequency RFID label chip with temperature sensing function.

Referring to Fig. 1, the passive ultra-high frequency RFID label chip with temperature sensing function of the present embodiment, comprise radio-frequency front-end, AFE (analog front end), digital baseband circuit, storer and temperature sensor, all circuit modules (are radio-frequency front-end, AFE (analog front end), digital baseband circuit, storer and temperature sensor, temperature sensor is connected with AFE (analog front end) with digital baseband circuit respectively) integrated circuit technology based on identical, can be made on same a slice silicon chip; Radio-frequency front-end, AFE (analog front end), digital baseband circuit and storer are connected successively, 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, storer and temperature sensor:

(1) radio-frequency front-end, is the interface circuit that label is communicated by letter with read write line, and the radio-frequency front-end of label chip is comprised of rectification circuit, demodulator circuit and modulation circuit.Rectification circuit is converted into the rf wave of reader transmitting the DC energy of label work; The radiofrequency signal that demodulator circuit sends from reader, extract envelope, after processing, send digital baseband circuit to and decode; The Data Modulation that modulation circuit returns to label is to radio frequency band, and sends to reader by antenna.

(2) AFE (analog front end), is comprised of mu balanced circuit, clock circuit and reset circuit.Mu balanced circuit is converted into galvanic current by the DC voltage of the less stable of rectification circuit output and presses, as the operating voltage of whole other partial circuits of chip; Clock circuit is an oscillator, produces for the required clock signal of digital baseband circuit work; 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) digital baseband circuit is decoded to the received signal and is responded, the dormancy of simultaneously controlling read-write operation to storer, temperature sensor with wake up, and control temperature sensor and carry out temperature sensing operation.

(4) memory stores goods attribute information, label ID, temperature data and user's data writing etc.

(5) temperature sensor, comprises that temperature information gathers front-end circuit and analog to digital converter.Temperature information gathers the voltage being directly proportional to temperature of front-end circuit generation and represents current ambient temperature information, also produces a temperature independent reference voltage as analog-to-digital reference voltage; Analog to digital converter is converted to digital signal by the voltage signal that indicates temperature information.

Especially, referring to Fig. 2, temperature information gathers front-end circuit, comprises PMOS pipe MP1～MP8, and NMOS manages MN1～MN16.Wherein, the source electrode of PMOS pipe MP1～MP8 all links together and is connected to the supply voltage that temperature information gathers front-end circuit, and the mu balanced circuit of this supply voltage in AFE (analog front end) provides, the grid of PMOS pipe MP1～MP8 all links together and is connected to the drain electrode of MP2, the drain electrode of PMOS pipe MP1～MP7 is connected to respectively the drain electrode of NMOS pipe MN1～MN7, the grid of NMOS pipe MN1 is connected with drain electrode and links together with the grid of NMOS pipe MN2, the grid of NMOS pipe MN8 is connected with drain electrode and links together with the grid of NMOS pipe MN9, the source electrode of NMOS pipe MN1 and NMOS pipe MN2 is connected with the drain electrode of NMOS pipe MN9 with NMOS pipe MN8 respectively, the source electrode of NMOS pipe MN9 is connected with the drain electrode of NMOS pipe MN15, grid separately of NMOS pipe MN3～MN7 and their drain electrode are connected, and be connected with the grid of NMOS pipe MN10～MN14 respectively, the source electrode of NMOS pipe MN3～MN7 is connected with the drain electrode of NMOS pipe MN10～MN14 respectively, the source electrode of NMOS pipe MN11 is connected to the drain electrode of NMOS pipe MN10, the source electrode of NMOS pipe MN12 is connected to the drain electrode of NMOS pipe MN11 and is connected with the source electrode of NMOS pipe MN16, the grid of NMOS pipe MN16 links together with drain electrode and is connected and as temperature information, gathers the reference voltage V REF of front-end circuit output with the drain electrode of NMOS pipe MN8 and the grid of NMOS pipe MN15, the source electrode of NMOS pipe MN13 is connected with the drain electrode of NMOS pipe MN12, the source electrode of NMOS pipe MN14 is connected with the drain electrode of NMOS pipe MN12, the voltage VPTAT that the temperature that the drain electrode of NMOS pipe MN14 is exported as temperature information collection front-end circuit is directly proportional, NMOS manages MN8, NMOS manages MN15, the source electrode of NMOS pipe MN10 is connected to ground.

The current mirror that PMOS pipe MP1-MP7 forms is mirrored to other each branch roads by reference current.NMOS pipe MN3-MN14 is operated in sub-threshold region, and the principle of utilizing the difference of the gate source voltage of sub-threshold region metal-oxide-semiconductor to be directly proportional to absolute temperature produces the voltage of one be directly proportional to temperature (PTAT), and this PTAT voltage expression formula is as follows:

V PTAT = V gs 10 - V gs 3 + V gs 11 - V gs 4 + V gs 12 - V gs 5 + V gs 13 - V gs 6 + V gs 14 - V gs 7 = η V T ln ( K 3 / K 10 ) + η V T ln ( K 4 / K 11 ) + η V T ln ( K 5 / K 12 ) + η V T ln ( K 6 / K 13 ) + η V T ln ( K 7 / K 14 ) = η V T ln K 3 K 4 K 5 K 6 K 7 K 10 K 11 K 12 K 13 K 14 ;

Wherein, η is the sub-threshold slope factor, V _tfor thermal voltage, K represents the breadth length ratio of NMOS pipe.

Because the gate source voltage of metal-oxide-semiconductor becomes negative linear relationship with temperature, NMOS is managed to the gate source voltage of MN16 and a part for VPTAT voltage stack, by Circuit tuning parameter reasonably, at the grid of NMOS pipe MN16, produce one and keep constant reference voltage with temperature.The expression formula of reference voltage is as follows:

V REF = V gs 16 + V gs 10 - V gs 3 + V gs 11 - V gs 4 = 2 I d μ C ox k + V th + η V T ln K 3 K 4 K 10 K 11 .

In the passive ultra-high frequency RFID label chip with temperature sensing function of above-described embodiment, temperature sensor adopts the cmos device identical with label chip technique to realize, and the chip area of increase is very little; Meanwhile, the temperature characterisitic of the cmos device based on sub-threshold region work, has designed temperature information Acquisition Circuit, greatly reduces 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, based on CMOS integrated circuit technology, realize temperature sensor, traditional electronic label chip and temperature sensor are combined, on a slice silicon chip, realize temperature sensing function and radio frequency recognition function; The passive ultra-high frequency RFID label chip that this has temperature sensing function, have advantages of low in energy consumption, area is little, packaging cost is low.

Finally it should be noted that: the foregoing is only the preferred embodiments of the present invention, be not limited to the present invention, although the present invention is had been described in detail with reference to previous embodiment, for a person skilled in the art, its technical scheme that still can record aforementioned each embodiment is modified, or part technical characterictic is wherein equal to replacement.Within the spirit and principles in the present invention all, any modification of doing, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.