KR20100138033A - Sensing device of rfid - Google Patents

Abstract

PURPOSE: The sensing device of radio-frequency-identification(RFID) is provided to reduce the area of a sensing circuit by simplifying the sensing circuit using a look-up table. CONSTITUTION: A temperature sensing part(100) converts temperature measured from RFID into a voltage. A temperature sensing part compares the converted voltage with a lamp voltage. A counting part(140) counts the number of clocks according to the output of the temperature sensing part. A temperature memory part(150) allocates standard address corresponding to standard temperature. An outputting part(170) compares the output of the counting part and the output of the temperature memory part.

Description

Sensing device of RFID

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensing device of RFID, and is a technology for reducing the area of the sensing circuit and precisely adjusting the temperature by simply configuring a sensing circuit using a look-up-table (LUT).

RFID (Radio Frequency IDentification Tag Chip) is a contactless automatic identification method that communicates with an RFID reader by attaching an RFID tag to an object to be identified and automatically transmitting and receiving it by using a wireless signal. To provide technology. As RFID is used, it is possible to compensate for the disadvantages of the conventional automatic identification technology, barcode and optical character recognition technology.

Recently, RFID tags have been used in various cases, such as logistics management systems, user authentication systems, electronic money systems, transportation systems.

For example, in the logistics management system, cargo classification or inventory management is performed using an integrated circuit (IC) tag in which data is recorded instead of a delivery slip or a tag. In the user authentication system, admission management and the like are performed using an IC card that records personal information and the like.

Meanwhile, a nonvolatile ferroelectric memory may be used as a memory used for an RFID tag.

In general, nonvolatile ferroelectric memory, or ferroelectric random access memory (FeRAM), has a data processing speed of about dynamic random access memory (DRAM) and is attracting attention as a next-generation memory device because of its characteristic that data is preserved even when the power is turned off. have.

The FeRAM is a device having a structure almost similar to that of a DRAM, and uses a ferroelectric capacitor as a memory device. Ferroelectrics have a high residual polarization characteristic, and as a result, the data is not erased even when the electric field is removed.

1 is an overall configuration diagram of a general RFID device.

The RFID device according to the related art includes an antenna unit 1, an analog unit 10, a digital unit 20, and a memory unit 30.

Here, the antenna unit 1 serves to receive a radio signal transmitted from an external RFID reader. The wireless signal received through the antenna unit 1 is input to the analog unit 10 through the antenna pads 11 and 12.

The analog unit 10 amplifies the input wireless signal to generate a power supply voltage VDD which is a driving voltage of the RFID tag. The operation command signal is detected from the input wireless signal, and the command signal CMD is output to the digital unit 20. In addition, the analog unit 10 senses the output voltage VDD and outputs a power-on reset signal POR and a clock signal CLK to the digital unit 20 for controlling the reset operation.

The digital unit 20 receives the power supply voltage VDD, the power-on reset signal POR, the clock signal CLK, and the command signal CMD from the analog unit 10, and outputs a response signal RP to the analog unit 10. The digital unit 20 also outputs the address ADD, input / output data I / O, control signal CTR, and clock CLK to the memory unit 30.

In addition, the memory unit 30 reads / writes data using a memory element and stores the data.

Here, the RFID device uses a frequency of several bands, the characteristics of which vary depending on the frequency band. In general, the lower the frequency band, the slower the recognition speed, the RFID device operates in a short distance, and is less affected by the environment. On the contrary, the higher the frequency band, the faster the recognition speed and the longer the distance is affected by the environment.

The most preferable method for testing whether the RFID tag is operating normally is as follows. Applying a radio signal through the antenna pad (11, 12) of the individual RFID tag, modulates the response signal RP generated by processing the radio signal by the digital unit 20 inside the RFID tag and transmits to the RFID reader, RFID It is to check whether the signal received from the reader is the desired signal.

However, the sensor for measuring the temperature, humidity, pressure, light, etc. inside the RFID has a complicated configuration of the sensing circuit and a large circuit area. Accordingly, there is a problem that the cost of the RFID device increases.

The present invention was created to solve the above problems, and by simply configuring the sensing circuit using a look-up-table (LUT), the area of the sensing circuit can be reduced and the temperature can be finely adjusted. There is a purpose.

In addition, an object of the present invention is to simply configure a sensing circuit using a look-up table (LUT) to reduce the area of the sensing circuit and to precisely adjust humidity, pressure, light, and the like.

In the RFID sensing device of the present invention for achieving the above object, in the RFID sensing device for sensing the temperature of the RFID including an analog unit, a digital unit and a memory unit, converts the temperature measured in the RFID into a voltage and ramp Temperature sensing means for comparing with a voltage; Counting means for counting the number of clocks in accordance with the output of the temperature sensing means; A temperature memory for allocating a standard address corresponding to the standard temperature and pre-store the output data of the counting means in the corresponding area of the standard address; And output means for comparing the output of the counting means with the output of the temperature memory and selectively outputting the output data applied from the temperature memory to the RFID according to the comparison result.

The present invention provides an RFID sensing device for sensing a state of an RFID including an analog unit, a digital unit, and a memory unit, comprising: sensing means for converting a sensing parameter measured by the RFID into a sensing voltage and comparing the sensing voltage with a lamp voltage; Counting means for counting the number of clocks in accordance with the output of the sensing means; A memory for allocating a standard address corresponding to the standard sensing data and previously storing the output data of the counting means in a corresponding area of the standard address; And output means for comparing the output of the counting means with the output of the memory and selectively outputting data applied from the memory to the RFID according to the comparison result.

As described above, the present invention provides a simple configuration of the sensing circuit using a look-up-table (LUT) to reduce the area of the sensing circuit and to precisely adjust temperature, humidity, pressure, and light. Provide effect.

In addition, the preferred embodiment of the present invention is for the purpose of illustration, those skilled in the art will be able to various modifications, changes, replacements and additions through the spirit and scope of the appended claims, such configuration changes, etc. It should be seen as belonging to a range.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is an overall configuration diagram of a sensing device of RFID according to the present invention.

The present invention provides a temperature-to-voltage converter (100), a lamp voltage generator (110), a comparator (120), a logic combination unit (130), an N-bit counter (140), The temperature memory 150 includes a comparator 160, an output buffer 170, and an RFID interface unit 200.

Here, the temperature-voltage converter 100, the ramp voltage generator 110, the comparator 120 and the logic combination unit 130 correspond to temperature sensing means, and the N-bit counter 140 is counting means. Corresponds to The comparator 160, the output buffer 170, and the RFID interface unit 200 correspond to output means.

The temperature-voltage converter 100 senses the internal temperature of the RFID, converts it into a voltage, and outputs a voltage Vtemp. The temperature-voltage converter 100 converts the internal temperature characteristic of the RFID into a voltage characteristic.

The lamp voltage generator 110 generates a lamp voltage Vramp according to the reset signal RESET and outputs the lamp voltage Vramp to the comparator 120. According to the ramp voltage generator 110, the ramp voltage Vramp has a constant linear voltage characteristic after a reset operation.

The comparator 120 compares the voltage Vtemp and the ramp voltage Vramp and outputs the enable signal CNT_EN. Here, the comparator 120 is applied with the voltage Vtemp through the positive (+) terminal, and the lamp voltage Vramp through the negative (-) terminal.

Accordingly, the comparator 120 outputs the enable signal CNT_EN to a high level in a section in which the voltage Vtemp level is higher than the ramp voltage Vramp level. On the other hand, the comparator 120 outputs the enable signal CNT_EN at a low level in a section in which the voltage Vtemp level is lower than the ramp voltage Vramp level.

The logic combination unit 130 performs an AND operation on the enable signal CNT_EN and the clock CLK to output the clock enable signal CLK_EN. Here, the logic combination unit 130 includes an AND gate AND1 for ANDing the enable signal CNT_EN and the clock CLK. Accordingly, the logic combination unit 130 outputs the clock CLK only in the section in which the enable signal CNT_EN is at a high level.

The N-bit counter 140 counts the number of clocks CLK as N-bit data according to the clock enable signal CLK_EN. Data counted in the N-bit counter 140 is output to the temperature memory 150 and the comparator 160.

The temperature memory 150 includes a look-up table that stores standard temperature data. Here, the look-up table sets a desired standard temperature value in advance in many cases, sets a standard address corresponding to the set standard temperature, and outputs data corresponding to the address when the corresponding standard address is input. To implement the circuit.

The temperature memory 150 receives data counted by the N-bit counter 14 through the write terminal W_P and stores the data in the lookup table. The temperature memory 150 outputs the data stored in the lookup table to the comparator 160 through the read terminal R_P. In addition, the temperature memory 150 outputs m-bit data to the output buffer 170 through the output terminal O_P.

In addition, the comparator 160 has a positive (+) terminal connected to the lead terminal R_P of the temperature memory 150, and a negative (-) terminal connected to the write terminal W_P of the temperature memory 150. The comparator 160 compares the output data of the N-bit counter 140 with the output data applied through the read terminal R_P of the temperature memory 150 and outputs the output enable signal OE to the output buffer 170.

The output buffer 170 buffers m-bit data, which is an output of the temperature memory 150, and outputs the buffered m-bit data to the RFID interface unit 200 according to the output enable signal OE. That is, when the output enable signal OE is at a high level, the output buffer 170 buffers the m-bit data applied through the output terminal O_P of the temperature memory 150 and outputs the buffered m-bit data to the RFID interface unit 200.

The RFID interface unit 200 converts the m-bit data applied from the output buffer 170 and transmits the m-bit data to the memory unit of the RFID tag, for example, the RFID tag. Accordingly, the RFID tag stores the temperature information sensed by the sensing device in the memory unit.

Herein, a nonvolatile ferroelectric memory (FeRAM) may be used as the memory unit of the RFID tag. In this case, the memory unit of the RFID tag may non-volatilely store temperature information applied from the RFID interface unit 200.

FeRAM has a data processing speed of about DRAM. In addition, FeRAM has a structure almost similar to DRAM, and has a high residual polarization characteristic of the ferroelectric by using a ferroelectric as the material of the capacitor. Due to this residual polarization characteristic, data is not erased even when the electric field is removed.

3 is a detailed configuration of a lookup table of the temperature memory 150 of FIG. 2.

The temperature memory 150 assigns a standard address corresponding to each standard temperature. Then, the output data of the N-bit counter 140 measured at each standard temperature is input through the write terminal W_P and stored in each assigned standard address.

For example, when the standard temperature is 25 degrees, the standard address is designated as '0', and when the standard temperature is 26 degrees, the standard address is designated as '1'. When the standard temperature is 27 degrees, the standard address is designated as '2', when the standard temperature is 28 degrees, the standard address is designated as '3', and when the standard temperature is 29 degrees, the standard address is designated as '4'. The N-bit data, which is the output of the N-bit counter 140, is allocated to the corresponding standard address and stored.

4 is a flowchart for describing a method of storing measured standard temperature data in the temperature memory 150 in an initial setting step.

First, the standard address corresponding to the standard temperature is set in the initial chamber (Chamber) as shown in FIG. 3 (step S1).

Next, the N-bit counter 140 performs a counting operation synchronized with the clock CLK according to the clock enable signal CLK_EN (step S2).

Subsequently, the N-bit data measured by the N-bit counter 140 is stored in the lookup table through the write terminal W_P of the temperature memory 150 (step S3).

Next, all standard temperatures are measured to determine whether or not they have been stored in the lookup table of the temperature memory 150 (step S4).

If all standard temperatures are measured and not stored in the lookup table, the standard temperature setting is increased and changed (step S5).

Thereafter, the corresponding standard temperature and standard address are reset (step S6).

That is, until all the standard temperatures are measured and data is stored in the lookup table, the standard temperature and the standard address are changed and the measurement results of the standard data are stored again.

Accordingly, the temperature-voltage converter 100, the lamp voltage generator 110, the comparator 120, the logic combiner 130, and the N-bit counter 140 may be changed in the initial temperature calibration step. The corresponding data is stored in advance in the lookup table of the temperature memory 150.

5 is a flowchart illustrating a temperature measuring method of a sensing device according to the present invention.

First, the standard temperature value corresponding to the standard address in the initial operation is set to the smallest value. Accordingly, the current standard address is set to '0' in the lookup table of the temperature memory 150 (step S11).

Next, the N-bit data stored in the lookup table is output to the comparator 160 via the read terminal R_P of the temperature memory 150 (step S12).

Next, the comparator 160 compares the N-bit data output through the read terminal R_P of the temperature memory 150 with the output data of the N-bit counter 140 currently being measured (step S13).

Then, it is judged whether or not the output enable signal OE which is the output of the comparator 160 is output at a high level (step S14).

That is, when the data output through the read terminal R_P of the temperature memory 150 is larger than the output data of the N-bit counter 140 as a result of the comparison of the comparator 160, the output enable signal OE is output at a high level.

In this case, when the output enable signal OE output from the comparator 160 becomes a 'high' level, the output buffer 170 buffers m-bit data corresponding to a standard address and outputs the buffered data to the RFID interface unit 200. (Step S15)

On the other hand, when the data output through the read terminal R_P of the temperature memory 150 is smaller than the output data of the N-bit counter 140 as a result of the comparison of the comparator 160, the output enable signal OE is output at a low level. .

At this time, when the output enable signal OE output from the comparator 160 becomes the 'low' level, the standard address is increased (step S16).

In this case, the standard temperature stored in the lookup table is likely to be lower than the standard temperature currently measured at the sensor. This resets the standard address. (Step S17)

Here, if the standard address is gradually increased, the output enable signal OE transitions to a high level from any one or more standard addresses. In this way, the temperature value corresponding to the standard address at the time when the output enable signal OE transitions to the high level is output as the current temperature value.

FIG. 6 is a detailed circuit diagram of the temperature-voltage converter 100 of FIG. 2.

The temperature-voltage converter 100 includes a PMOS transistor P1 and a bipolar transistor Q1.

The bias element PMOS transistor P1 is connected between the supply voltage terminal and the output terminal of the voltage Vtemp, and the bias voltage Vbias is applied through the gate terminal. Here, the bias voltage Vbias is set so that a constant current is supplied regardless of the change in temperature.

The bipolar transistor Q1, which is a temperature detection means, serves as a diode. That is, the bipolar transistor Q1 measures the actual temperature through the P-type region operating as the anode region. The N-type region and the P-type region, which operate as the remaining collector regions, are connected to each other through collector terminals for stabilization of bias.

The bipolar transistor Q1 is connected between the output terminal of the voltage Vtemp and the ground voltage terminal, and the voltage Vtemp is applied through the base terminal.

FIG. 7 is a diagram for describing a temperature characteristic of the temperature-voltage converter 100 of FIG. 6. When the bias voltage Vbias is set in the temperature-voltage converter 100 so that a constant current is supplied regardless of the temperature change, the voltage Vtemp level is lowered by the bipolar transistor Q1 as the temperature increases. That is, when the temperature is low, the voltage Vtemp is high, and when the temperature is high, the voltage Vtemp is low.

FIG. 8 is a detailed circuit diagram illustrating the lamp voltage generator 110 of FIG. 2.

The ramp voltage generator 110 includes a PMOS transistor P2, an NMOS transistor N1, and a capacitor C1.

Here, the bias element PMOS transistor P2 is connected between the power supply voltage terminal and the output terminal of the ramp voltage Vramp and the bias voltage Vbias is applied through the gate terminal. The bias voltage Vbias is set to supply a constant current regardless of the change in temperature.

In addition, the switching element NMOS transistor N1 is connected between the output terminal of the ramp voltage Vramp and the ground voltage terminal, and a reset signal RESET is applied through the gate terminal. In addition, capacitor C1 is connected between the output terminal of the ramp voltage Vramp and the ground voltage terminal.

9 is a view for explaining a temperature characteristic of the lamp voltage generator 110 of FIG. 8.

First, the NMOS transistor N1 is turned on while the reset signal RESET is at a high level. Accordingly, the ramp voltage Vramp is set to the low level during the initial reset operation.

Subsequently, as time passes, the level of the lamp voltage Vramp increases linearly due to the influence of the PMOS transistor P2 and the capacitor C1 in the lamp voltage generator 110.

That is, the lamp voltage Vramp is output at a low level during the initial reset operation, and the lamp voltage Vramp increases linearly when a long time elapses.

FIG. 10 is a diagram for describing an operating characteristic of an enable signal CNT_EN according to a ramp voltage Vramp according to the present invention.

First, at high and low temperatures, the voltage level of the voltage Vtemp is constantly output. At time t1 at which the enable signal CNT_EN is output, the lamp voltage Vramp is at a level lower than the voltage Vtemp at a high temperature. When the time t1 elapses and the time t2 at which the enable signal CNT_EN is output, the lamp voltage Vramp becomes a level lower than the voltage Vtemp at low temperature.

Since the activation time of the enable signal CNT_EN is changed according to the temperature, the output of the N-bit counter 140 is also changed.

FIG. 11 is a diagram for describing a counting activation operation region in the N-bit counter 140 of FIG. 2.

First, in the reset mode, when the reset signal RESET is at a high level, the lamp voltage Vramp is at a low level. On the other hand, when the reset signal RESET is at a low level, the ramp voltage Vramp gradually increases due to the influence of the PMOS transistor P2 and the capacitor C1.

Subsequently, when the ramp voltage Vramp rises, the enable signal CNT_EN transitions to a high level at a certain point in time.

Then, both the clock CLK and the enable signal CNT_EN which are inputs of the AND gate AND1 are activated, and the clock enable signal CLK_EN is activated and output to the N-bit counter 140. Accordingly, the N-bit counter 140 counts the number of clocks during the activation period of the clock enable signal CLK_EN to output N-bit data.

12 is another embodiment of a sensing device of an RFID device according to the present invention.

The present invention provides a sensing-to-voltage converter 300, a ramp voltage generator 310, a comparator 320, a logic combination unit 330, an N-bit counter 340, The memory 350 includes a comparator 360, an output buffer 370, and an RFID interface unit 380.

Here, the sensing-voltage converter 300 senses a state of an internal temperature, humidity, pressure, light, etc. of the RFID, converts the voltage into a voltage, and outputs a sensing voltage Vsensing. The sensing-voltage converter 300 converts the characteristics of the RFID such as internal temperature, humidity, pressure, and light into voltage characteristics.

The lamp voltage generator 310 generates a lamp voltage Vramp according to the reset signal RESET and outputs the lamp voltage Vramp to the comparator 320. According to the ramp voltage generator 310, the ramp voltage Vramp has a constant linear voltage characteristic after the reset operation.

The comparator 320 compares the sensing voltage Vsensing and the ramp voltage Vramp and outputs the enable signal CNT_EN. Here, the comparator 320 is applied with the sensing voltage Vsensing through the positive (+) terminal and the ramp voltage Vramp through the negative (-) terminal.

Accordingly, the comparator 320 outputs the enable signal CNT_EN to a high level in a section in which the sensing voltage Vsensing level is higher than the ramp voltage Vramp level. On the other hand, the comparator 320 outputs the enable signal CNT_EN at a low level in a section in which the sensing voltage Vsensing level is lower than the ramp voltage Vramp level.

The logic combination unit 330 performs an AND operation on the enable signal CNT_EN and the clock CLK to output the clock enable signal CLK_EN. Here, the logic combination unit 330 includes an AND gate AND2 for ANDing the enable signal CNT_EN and the clock CLK. Accordingly, the logic combination unit 330 outputs the clock CLK only in the section in which the enable signal CNT_EN is at a high level.

The N-bit counter 340 counts the number of clocks CLK as N-bit data according to the clock enable signal CLK_EN. Data counted by the N-bit counter 340 is output to the memory 350 and the comparator 360.

The memory 350 includes a look-up table that stores standard sensing data. The memory 350 receives data counted by the N-bit counter 340 through the write terminal W_P and stores the data in the lookup table. The memory 350 outputs data stored in the lookup table to the comparator 360 through the read terminal R_P. In addition, the memory 350 outputs m-bit data to the output buffer 370 through the output terminal O_P.

In addition, the comparator 360 has a positive (+) terminal connected to the lead terminal R_P of the memory 350, and a negative (-) terminal connected to the write terminal W_P of the memory 350. The comparator 360 compares the output data of the N-bit counter 340 with the output data applied through the read terminal R_P of the memory 350 and outputs an output enable signal OE to the output buffer 370.

The output buffer 370 buffers m-bit data, which is an output of the memory 350, and outputs the buffered m-bit data to the RFID interface unit 380 according to the output enable signal OE. That is, when the output enable signal OE is at the high level, the output buffer 370 buffers the m-bit data applied through the output terminal O_P of the memory 350 and outputs the buffered m-bit data to the RFID interface unit 380.

The RFID interface unit 380 converts m-bit data applied from the output buffer 370 and transmits the m-bit data to the memory unit of the RFID tag, for example, the RFID tag. Accordingly, the RFID tag stores state information such as temperature, humidity, pressure, and light sensed by the sensing device in the memory unit.

Herein, a nonvolatile ferroelectric memory (FeRAM) may be used as the memory unit of the RFID tag. In this case, the memory unit of the RFID tag may non-volatile store state information of the RFID applied from the RFID interface unit 38.

FeRAM has a data processing speed of about DRAM. In addition, FeRAM has a structure almost similar to DRAM, and has a high residual polarization characteristic of the ferroelectric by using a ferroelectric as the material of the capacitor. Due to this residual polarization characteristic, data is not erased even when the electric field is removed.

The embodiment of FIG. 12 having such a configuration enables the sensor of the RFID to sense a parameter such as humidity, pressure, or light, instead of only detecting temperature.

FIG. 13 is a diagram for describing sensing characteristics of the sensing-voltage converter 300 of FIG. 12. When the sensing parameter such as temperature, humidity, pressure, or light is increased in the sensing-voltage converter 300, the sensing voltage Vsensing level decreases. That is, when the sensing parameter is low, the sensing voltage Vsensing becomes high, and when the sensing parameter is high, the sensing voltage Vsensing becomes low.

1 is an overall configuration diagram of a conventional RFID device.

2 is an overall configuration diagram of a sensing device of RFID according to the present invention.

3 is a detailed block diagram of a lookup table of the temperature memory of FIG. 2;

4 is a flowchart for explaining a data storage method of the temperature memory of FIG. 2.

5 is a flowchart illustrating a method for measuring a temperature of a sensing device according to the present invention.

FIG. 6 is a detailed circuit diagram of the temperature-voltage converter of FIG. 2. FIG.

7 is a view for explaining the temperature characteristic of FIG. 6.

FIG. 8 is a detailed circuit diagram of the lamp voltage generator of FIG. 2. FIG.

FIG. 9 is a view for explaining temperature characteristics of a lamp voltage generator of FIG. 8; FIG.

FIG. 10 is a diagram for describing operation characteristics of a ramp voltage and an enable signal of FIG. 2. FIG.

11 is a view for explaining the operation of the N-bit counter of FIG.

12 is another embodiment of a sensing device of RFID according to the present invention.

FIG. 13 is a diagram for describing sensing characteristics of the sensing-voltage converter of FIG. 12. FIG.

Claims (13)

In the RFID sensing device for sensing the temperature of the RFID including an analog unit, a digital unit and a memory unit, Temperature sensing means for converting the temperature measured in the RFID into a voltage and comparing it with a lamp voltage; Counting means for counting the number of clocks in accordance with the output of the temperature sensing means; A temperature memory for allocating a standard address corresponding to a standard temperature and previously storing the output data of the counting means in a corresponding area of the standard address; And And an output means for comparing the output of the counting means and the output of the temperature memory, and selectively outputting the output data applied from the temperature memory to the RFID according to the comparison result. The method of claim 1, wherein the temperature sensing means A temperature-voltage converter converting the temperature measured by the RFID into a first voltage; A lamp voltage generator configured to generate a lamp voltage according to a reset signal; A first comparator comparing the first voltage with the ramp voltage and outputting an enable signal; And And logic combining means for outputting a clock enable signal synchronized with a clock upon activation of the enable signal. The method of claim 2, wherein the temperature-voltage converter A first bias element for supplying a constant current regardless of the temperature change; And And a temperature detecting means for outputting the first voltage corresponding to the change in temperature in accordance with the output current of the first bias element. The method of claim 2 or 3, wherein the temperature-voltage converter The sensing device of the RFID, characterized in that as the temperature increases, the voltage level of the first voltage is lowered. The method of claim 2, wherein the lamp voltage generating unit A second bias element for supplying a constant current regardless of the change in temperature; A switching element for initializing the lamp voltage upon activation of the reset signal; And And a capacitor device for adjusting the voltage level of the ramp voltage. The method of claim 2 or 5, wherein the lamp voltage generating unit And a level of the ramp voltage increases linearly after a reset operation. The sensing device of claim 1, wherein the temperature memory stores the output data of the counting means in a corresponding address area of a look-up table. The method of claim 1, wherein the output means A second comparator for comparing the output of the counting means with the output of the temperature memory; And And an output buffer for selectively outputting output data of the temperature memory to the RFID according to a comparison result of the second comparator. The sensing device according to claim 1 or 8, further comprising an interface unit for exchanging data between the output means and the RFID. An RFID sensing device for sensing a state of an RFID including an analog unit, a digital unit, and a memory unit, Sensing means for converting a sensing parameter measured by the RFID into a sensing voltage and comparing it with a ramp voltage; Counting means for counting the number of clocks in accordance with the output of the sensing means; A memory for allocating a standard address corresponding to standard sensing data and pre-stores output data of the counting means in a corresponding area of the standard address; And And an output means for comparing the output of the counting means and the output of the memory, and selectively outputting data applied from the memory to the RFID according to the comparison result. The sensing device of RFID, wherein the sensing parameter is any one of temperature, humidity, pressure, and light. The sensing device of claim 10 or 11, wherein the sensing means lowers the level of the sensing voltage when the value of the sensing parameter increases. The sensing device of claim 10, wherein the ramp voltage has a linearly increasing characteristic.

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