CN115146747A - Digital temperature sensor and passive radio frequency tag comprising same - Google Patents
Digital temperature sensor and passive radio frequency tag comprising same Download PDFInfo
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- G06K17/00—Methods or arrangements for effecting co-operative working between equipments covered by two or more of main groups G06K1/00 - G06K15/00, e.g. automatic card files incorporating conveying and reading operations
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Abstract
The embodiment of the invention provides a digital temperature sensor and a passive radio frequency tag comprising the same. The digital temperature sensor includes: the radio frequency induction module is used for inducing a radio frequency signal generated by active radio frequency equipment; the field clock recovery module is connected with the radio frequency induction module and used for generating a clock signal based on the radio frequency signal; a temperature detection module to detect an ambient temperature and generate a voltage signal related to the ambient temperature; the signal conversion module is connected with the temperature detection module and used for converting the voltage signal into a pulse signal related to the ambient temperature; and the counting module is respectively connected with the field clock recovery module and the signal conversion module and used for counting the pulse signals based on the clock signals so as to obtain a counting result. The digital temperature sensor can realize passive high-precision temperature measurement without an additional clock circuit, and has the advantages of simple circuit structure, small area, low power consumption and contribution to saving the cost.
Description
Technical Field
The invention relates to the technical field of radio frequency, in particular to a digital temperature sensor and a passive radio frequency tag comprising the same.
Background
With the development of radio frequency technology, passive radio frequency tags are often used to detect ambient temperature and transmit and record data in many application scenarios, such as cold-chain logistics. However, the communication, digital processing and temperature measurement of the passive radio frequency tag all need a clock circuit, especially a high-precision digital temperature sensor, and the requirements on the precision and deviation of the clock are higher.
In the prior art, a ring oscillator, a resistance-capacitance oscillator and the like are usually adopted to generate a clock, a digital temperature sensor is limited by poor clock precision and temperature characteristics and cannot realize high precision, or a clock circuit is additionally added to realize high precision, so that the power consumption and the area of a chip are increased.
Disclosure of Invention
An object of an embodiment of the present invention is to provide a digital temperature sensor and a passive rf tag including the same.
The embodiment of the invention provides a digital temperature sensor, which comprises: the radio frequency induction module is used for inducing a radio frequency signal generated by active radio frequency equipment; the field clock recovery module is connected with the radio frequency induction module and used for generating a clock signal based on the radio frequency signal; a temperature detection module to detect an ambient temperature and generate a voltage signal related to the ambient temperature; the signal conversion module is connected with the temperature detection module and used for converting the voltage signal into a pulse signal related to the ambient temperature; and the counting module is respectively connected with the field clock recovery module and the signal conversion module and used for counting the pulse signals based on the clock signals so as to obtain a counting result.
Optionally, the radio frequency sensing module comprises an NFC sensing module.
Optionally, the field clock recovery module comprises an inverter cascade circuit, a latch circuit, or a comparison generation circuit.
Optionally, the temperature detection module comprises a bipolar transistor temperature sensor, a metal oxide semiconductor field effect transistor temperature sensor, or a resistance temperature sensor.
Optionally, the signal conversion module comprises a ramp signal generator and a comparator; the ramp signal generator is used for generating a ramp signal; the comparator is respectively connected with the temperature detection module and the ramp signal generator and used for receiving and comparing the magnitudes of the voltage signal and the ramp signal and generating and outputting a pulse signal based on the comparison result.
Optionally, the ramp signal generator is connected to the temperature detection module for generating the ramp signal based on the voltage signal.
Optionally, the ramp signal increases with time and stops when increasing to the voltage signal.
Optionally, the comparator is configured to generate a first level signal of the pulse signal when the ramp signal is less than or equal to the voltage signal.
Optionally, the comparator is configured to flip the pulse signal from the first level signal to the second level signal when the ramp signal is stopped.
Optionally, the counting module is configured to count the first level signal to obtain a counting result of the first level signal.
Optionally, the digital temperature sensor further comprises a processor connected to the counting module for obtaining a digital signal based on the counting result.
The passive radio frequency tag provided by the embodiment of the invention comprises the digital temperature sensor.
Compared with the prior art, the method has the advantages that, the technical scheme of the embodiment of the invention has the beneficial effect.
For example, by recovering the field clock generated by the active radio frequency device, not only an additional clock generation circuit is not needed, but also clocks with high precision (a clock signal recovered based on the field clock is a high-precision clock) and low temperature drift (the clock signal recovered based on the field clock is irrelevant to the ambient temperature) can be generated on the basis of not increasing the power consumption and the area of the digital temperature sensor chip, so that the high precision of the digital temperature sensor is realized, and the power consumption, the area and the cost of the digital temperature sensor chip are reduced.
For example, the clock signal based on the field clock recovery has no special requirement for the voltage signal to be quantized, and can quantize the voltage signal proportional to the absolute temperature signal or complementary to the absolute temperature signal, which is not only beneficial to suppressing the noise jitter, but also beneficial to eliminating the process deviation.
For another example, when the digital temperature sensor is integrated in a passive radio frequency tag, the implementation is easy, the design complexity of the tag is not increased, and the cost of the tag is saved.
The invention will be further described with reference to the accompanying drawings. The same reference numerals may be used to designate the same elements in different embodiments in the drawings, and descriptions of the same elements in different embodiments and descriptions of prior art elements, features, effects, and the like may be omitted.
Drawings
FIG. 1 is a functional block diagram of a digital temperature sensor in an embodiment of the present invention;
FIG. 2 is another functional block diagram of a digital temperature sensor in an embodiment of the present invention;
FIG. 3 is a schematic diagram of a pulse signal generated in an embodiment of the present invention;
FIG. 4 is a diagram illustrating a key waveform of a pulse signal generated according to an embodiment of the present invention, wherein V 1 Indicating a first voltage signal, V, generated by a temperature detection module 2 Indicating a second voltage signal, V, generated by the temperature sensing module t1 Representing a first ramp signal, V, generated by a ramp signal generator t2 Representing the second ramp signal generated by the ramp signal generator, vcomp representing the pulse signal generated by the comparator, t 1 Representing the pulse width, t, of a first level signal in the pulse signal 1 ' denotes a pulse width, t, of a first and second level signal in the pulse signal 2 Indicating the pulse width, t, of a second first level signal in the pulse signal 2 ' denotes a pulse width of the second level signal among the pulse signals.
Detailed Description
In the prior art, a digital temperature sensor is limited by poor clock precision and temperature characteristics, so that high precision cannot be realized, or a clock circuit is additionally added for realizing high precision, so that the power consumption and the area of a chip are increased.
Different from the prior art, the embodiment of the invention provides a digital temperature sensor and a passive radio frequency tag comprising the same. The digital temperature sensor includes: the radio frequency induction module is used for inducing a radio frequency signal generated by active radio frequency equipment; the field clock recovery module is connected with the radio frequency induction module and used for generating a clock signal based on the radio frequency signal; a temperature detection module to detect an ambient temperature and generate a voltage signal related to the ambient temperature; the signal conversion module is connected with the temperature detection module and used for converting the voltage signal into a pulse signal related to the ambient temperature; and the counting module is respectively connected with the field clock recovery module and the signal conversion module and used for counting the pulse signals based on the clock signals so as to obtain a counting result.
Compared with the prior art, the technical scheme of the embodiment of the invention has the beneficial effect. For example, by recovering the field clock generated by the active radio frequency device, not only an additional clock generation circuit is not needed, but also clocks with high precision (the clock signal recovered based on the field clock is a high-precision clock) and low temperature drift (the clock signal recovered based on the field clock is not related to the ambient temperature) can be generated on the basis of not increasing the power consumption and the area of the digital temperature sensor chip, so that the high precision of the digital temperature sensor is realized, and the power consumption, the area and the cost of the digital temperature sensor chip are reduced.
In order to make the objects, features and advantages of the embodiments of the present invention more comprehensible, specific embodiments accompanied with figures are described in detail below. It is to be understood that the following specific examples are illustrative of the invention and are not to be construed as limiting the invention. In addition, for convenience of description, only a part of structures related to the present invention, not all of the structures, is shown in the drawings.
Fig. 1 is a schematic block diagram of a digital temperature sensor in an embodiment of the invention.
Referring to fig. 1, the digital temperature sensor 101 includes a radio frequency sensing module 110, a field clock recovery module 120, a temperature detection module 130, a signal conversion module 140, and a counting module 150.
Specifically, the rf sensing module 110 is configured to sense an rf signal generated by an active rf device; the field clock recovery module 120 is connected to the rf sensing module 110 for generating a clock signal based on the rf signal; the temperature detection module 130 is used for detecting the ambient temperature and generating a voltage signal related to the ambient temperature; the signal conversion module 140 is connected to the temperature detection module 130, and is configured to convert the voltage signal into a pulse signal related to the ambient temperature; the counting module 150 is respectively connected to the field clock recovery module 120 and the signal conversion module 140, and is configured to count the pulse signals generated by the signal conversion module 140 based on the clock signals generated by the field clock recovery module 120 to obtain a counting result.
In the specific implementation, the active radio frequency device (also referred to as a radio frequency card reader) refers to a radio frequency terminal with a power supply. For example, a mobile phone, a tablet computer, etc. supporting radio frequency functions.
In some embodiments, the active radio frequency device may comprise an active Near Field Communication (NFC) device.
In a particular implementation, the rf sensing module 110 may include an rf resonant circuit adapted to sense an rf signal generated by an active rf device.
In some embodiments, the radio frequency resonant circuit may employ a parallel resonant circuit. For example, the rf resonant circuit may be a resonant circuit formed by connecting the rf antenna 111 and the matching capacitor 112 in parallel, as shown in fig. 1. The rf antenna 111 is used for sensing rf signals, and the matching capacitor 112 is used for adjusting the resonant frequency of the rf antenna 111 to its operating frequency, so as to optimize the communication effect and energy receiving efficiency of the rf antenna 111.
In some embodiments, the radio frequency induction module 110 may include an NFC induction module. Accordingly, the radio frequency antenna 111 may comprise an NFC antenna. In this case, the matching capacitor 112 is used to adjust the resonant frequency of the NFC antenna to its operating frequency of 13.56Hz.
In an implementation, the rf signal induced by the rf induction module 110 is a sine wave signal. The field clock recovery module 120 is connected to the rf sensing module 110, and is configured to convert the sine wave signal sensed by the rf sensing module 110 into a square wave signal, and output the square wave signal as a clock signal to the counting module 150.
In particular implementations, field clock recovery module 120 may be implemented using any conventional means known in the art, such as an inverter cascade circuit, a latch circuit, or a comparison generation circuit.
In a specific implementation, the clock signal output to the counting module 150 is independent of the ambient temperature regardless of the circuit form used by the field clock recovery module 120.
Fig. 2 is another functional block diagram of a digital temperature sensor in an embodiment of the invention.
Referring to fig. 2, unlike the embodiment shown in fig. 1, the digital temperature sensor 102 may further include a processor 160 coupled to the counting module 150.
In some embodiments, the processor 160 is configured to obtain a digital signal corresponding to the ambient temperature based on the counting result generated by the counting module 150.
In other embodiments, the processor 160 may be further connected to the temperature detection module 130 and the signal conversion module 140, respectively, and configured to generate a temperature measurement enable signal and output the temperature measurement enable signal to the temperature detection module 130 and the signal conversion module 140, respectively, when the counting module 150 receives the clock signal output by the field clock recovery module 120.
In a specific implementation, the temperature detection module 130 and the signal conversion module 140 are adapted to start operating upon receiving the thermometry enable signal.
In a specific implementation, the temperature detection module 130 is configured to detect an ambient temperature and generate a voltage signal related to the ambient temperature based on the ambient temperature.
In particular implementations, the temperature detection module 130 may be implemented using any conventional means known in the art, such as a bipolar transistor temperature sensor, a metal oxide semiconductor field effect transistor temperature sensor, or a resistive temperature sensor.
In one embodiment, the voltage signal generated by the temperature detecting module 130 may be a signal Complementary to a absolute temperature (CTAT) signal, for example, a negative temperature coefficient voltage signal generated by a bipolar transistor temperature sensor.
According to the basic principle of the digital temperature sensor, a positive temperature coefficient voltage signal, namely a Proportional To Absolute Temperature (PTAT) signal, can be obtained by subtracting negative temperature coefficient voltage signals of two different current coefficients. Then, the proportional absolute temperature voltage signal and the complementary absolute temperature voltage signal (the smaller of the two complementary absolute temperature voltage signals can be selected) are added to obtain the voltage reference signal independent of the ambient temperature. Finally, the voltage signal proportional to the absolute temperature is divided by the voltage reference signal to obtain a temperature voltage signal proportional to the ambient temperature.
Specifically, two complementary absolute temperature voltage signals with different current coefficients, namely a first voltage signal and a second voltage signal, can be generated by the temperature detection module 130. If the first voltage signal is larger than the second voltage signal, the first voltage signal is subtracted from the second voltage signal to obtain a voltage signal proportional to the absolute temperature, the voltage signal proportional to the absolute temperature and the second voltage signal are added to obtain a voltage reference signal independent of the ambient temperature, and the voltage signal proportional to the absolute temperature is divided by the voltage reference signal to obtain a temperature voltage signal proportional to the ambient temperature.
Specifically, the temperature voltage signal may be expressed as follows:
μ(T)＝V PTAT /V ref ＝V PTAT /(V PTAT +V 2 )＝[α*(V 1 -V 2 )]/[α*(V 1 -V 2 )+V 2 ] (1)，
wherein, V PTAT Representing a voltage signal proportional to absolute temperature, V ref Representing a voltage reference signal, V 1 Representing a first voltage signal, V 2 Representing the second voltage signal, alpha representing a voltage signal proportional to and complementary to the absolute temperature signalThe conversion coefficient of (2).
Further from the basic principle of digital temperature sensors, the relationship between ambient temperature and temperature voltage signal is as follows:
T(℃)＝A*μ(T)+B (2)，
wherein, T represents an ambient temperature in celsius, a represents a kelvin temperature coefficient corresponding to a temperature range which can be covered by a voltage signal proportional to an absolute temperature, and B represents a conversion coefficient between the celsius and the kelvin temperatures, which may be-273.
Specifically, the kelvin temperature coefficient a is related to the device characteristics of the temperature detection module 130 itself. For example, if a bipolar transistor temperature sensor can cover a temperature range of 330 ℃, its kelvin temperature coefficient a = (330 + 273) K =603K. Thus, the relationship between ambient temperature and temperature voltage signal can be expressed as:
T(℃)＝603*μ(T)-273 (3)。
in an implementation, the signal conversion module 140 is connected to the temperature detection module 130, and is configured to convert the voltage signal (including the first voltage signal and the second voltage signal) generated by the temperature detection module 130 into a pulse signal related to the ambient temperature.
Fig. 3 is a schematic diagram of a principle of generating a pulse signal in an embodiment of the present invention.
Referring to fig. 3, the signal conversion module 140 may include a ramp signal generator 141 and a comparator 142.
Specifically, the ramp signal generator 141 is configured to generate a ramp signal; the comparator 142 is connected to the temperature detection module 130 and the ramp signal generator 141, respectively, for receiving and comparing the magnitudes of the voltage signal and the ramp signal, and generating a pulse signal based on the comparison result, and outputting the pulse signal to the counting module 150.
In a specific implementation, the ramp signal generator 141 may be connected to the temperature detection module 130 to generate a ramp signal based on the voltage signal generated by the temperature detection module 130.
In some embodiments, the ramp signal generator 141 may include a capacitor, and a charging voltage signal generated based on linearly charging the capacitor is used as the ramp signal. Wherein the charging voltage signal is generated based on the voltage signal generated by the temperature detection module 130.
Specifically, the capacitor may be charged at a certain current, and the charging of the capacitor may be stopped when a charging voltage signal of the capacitor reaches a voltage signal generated by the temperature detection module 130. Therefore, the charging voltage signal generated by the capacitor during the charging period is the ramp signal.
FIG. 4 is a diagram illustrating key waveforms for generating pulse signals according to an embodiment of the present invention. In the figure, V 1 Indicating a first voltage signal, V, generated by the temperature sensing module 130 2 Indicating a second voltage signal, V, generated by the temperature sensing module 130 t1 Represents the first ramp signal, V, generated by the ramp signal generator 141 t2 Denotes the second ramp signal generated by the ramp signal generator 141, vcomp denotes the pulse signal generated by the comparator 142, t 1 Representing the pulse width, t, of a first level signal in the pulse signal 1 ' denotes a pulse width, t, of a first and second level signal in the pulse signal 2 Indicating the pulse width, t, of a second first level signal in the pulse signal 2 ' denotes a pulse width of the second level signal among the pulse signals.
Referring to FIG. 4, in the embodiment of the present invention, the first voltage signal V 1 And a second voltage signal V 2 Can be generated at different time and are all voltage signals with constant magnitude.
In specific implementations, the first ramp signal V t1 Based on a first voltage signal V 1 Generating a second ramp signal V t2 Based on the second voltage signal V 2 And (4) generating.
Specifically, the first ramp signal V generated by the ramp signal generator 141 t1 Increases with time and increases to the first voltage signal V 1 Time-of-flight, i.e. first ramp signal V t1 To the first voltage signal V 1 Stops charging the capacitor.
The second ramp signal generated by the ramp signal generator 141Number V t2 Also increases with time and increases to the second voltage signal V 2 Time-of-flight, i.e. second ramp signal V t2 To the second voltage signal V 2 Stops charging the capacitor.
In particular implementations, the first voltage signal V related to the ambient temperature generated by the temperature detection module 130 can be 1 And a second voltage signal V 2 As a comparison reference signal of the comparator 142, and compares the first ramp signal V generated by the ramp signal generator 141 t1 And a second ramp signal V t2 And comparing with a comparison reference signal to generate a pulse signal Vcomp related to the ambient temperature based on the comparison result.
Specifically, the first ramp signal V t1 And a first voltage signal V 1 Comparing and applying a first ramp signal V t1 Is less than or equal to the first voltage signal V 1 Generating a first level signal and a first ramp signal V t1 And when the first level signal is stopped, the first level signal is enabled to be overturned to the first second level signal.
In some embodiments, the first level signal may be a low level signal and, correspondingly, the first second level signal is a high level signal.
In other embodiments, the first level signal may also be a high level signal, and correspondingly, the first second level signal is a low level signal.
In the embodiment of the invention, the pulse width t of the first level signal 1 And a first voltage signal V 1 Is correlated with the size of (c).
Specifically, since the capacitor corresponds to the first voltage signal V 1 The maximum charging voltage signal of the charging stage is equal to the first voltage signal V 1 Thus, the pulse width t of the first level signal 1 Is equal to the capacitor corresponding to the first voltage signal V 1 A first charging time of the charging phase. Assuming that the capacitance value of the capacitor is C and the charging current is Ic, the following relationship can be obtained:
V 1 ＝(Ic/C)*t 1 (4)。
in the embodiment of the invention, the pulse width t of the first and second level signals 1 ' with a first voltage signal V 1 Is irrelevant to the size of the device.
In specific implementation, the pulse width t of the first and second level signals 1 ' it is not required, and it is sufficient if there is a rising edge (when the first and second level signals are high level signals) or a falling edge (when the first and second level signals are low level signals).
In a specific implementation, the pulse width t of the first and second level signals 1 ' may be small and may be ignored, for example, in the embodiment shown in FIG. 4.
In specific implementation, when the pulse signal Vcomp is inverted from the first level signal to the first second level signal, there is a certain delay, but the delay is very small, usually several nanoseconds, which does not substantially affect the implementation of the technical solution provided by the embodiment of the present invention. Thus, this delay is not shown in the embodiment shown in FIG. 4.
In a specific implementation, the second ramp signal V t2 And a second voltage signal V 2 Comparing and applying a second ramp signal V t2 Is less than or equal to the second voltage signal V 2 Generating a second first level signal and a second ramp signal V t2 And when the first level signal is stopped, the second first level signal is enabled to be overturned to a second level signal.
In some embodiments, the second first level signal may be a low level signal and, correspondingly, the second level signal is a high level signal.
In other embodiments, the second first level signal may also be a high level signal, and correspondingly, the second level signal is a low level signal.
In the embodiment of the invention, the pulse width t of the second first level signal 2 And a second voltage signal V 2 Is related to the size of (a).
Specifically, since the capacitor corresponds to the second voltage signal V 2 The maximum charging voltage signal of the charging stage is equal to the second voltage signal V 2 Of a signal of the second first levelPulse width t 2 Is equal to the capacitor corresponding to the second voltage signal V 2 A second charging time of the charging phase. Assuming that the capacitance value of the capacitor is C and the charging current is Ic, the following relationship can be obtained:
V 2 ＝(Ic/C)*t 2 (5)。
in the embodiment of the invention, the pulse width t of the second level signal 2 ' with a second voltage signal V 2 Is irrelevant.
In specific implementation, the pulse width t of the second level signal 2 ' it is not required, and it is sufficient if there is a rising edge (when the second level signal is a high level signal) or a falling edge (when the second level signal is a low level signal).
In a specific implementation, the pulse width t of the second level signal 2 ' can be small and negligible.
In specific implementation, when the pulse signal Vcomp is flipped from the second first level signal to the second level signal, there is a certain delay, but the delay is very small, usually several nanoseconds, and the implementation of the technical solution provided by the embodiment of the present invention is not substantially affected.
Based on the above scheme, the pulse signal Vcomp generated by the comparator 142 includes the first level signal and the second first level signal, and the pulse width t of the first level signal 1 And the pulse width t of the second first level signal 2 Respectively corresponding to the first voltage signal V 1 And a second voltage signal V 2 Is related to the magnitude of the first voltage signal V 1 And a second voltage signal V 2 Is related to the ambient temperature, and thus the pulse signal Vcomp generated by the comparator 142 is related to the ambient temperature.
In an implementation, the counting module 150 is configured to receive the clock signal generated by the field clock recovery module 120 and the pulse signal Vcomp generated by the signal conversion module 140, and the pulse width t of the first level signal of the pulse signal Vcomp may be determined based on the clock signal 1 And the pulse width of the second first level signalt 2 Counting to obtain the pulse width t of the first level signal 1 First counting result N 1 And the pulse width t of the second first level signal 2 Second counting result N 2 。
In some embodiments, the counting module 150 may employ a pulse counter directly.
In some embodiments, the counting module 150 may count the pulse width t of the first level signal 1 First counting result N 1 And the pulse width t of the second first level signal 2 Second counting result N 2 Output to a processing device external to the digital temperature sensor so that the external processing device can base on the first count result N 1 And a second counting result N 2 And a digital signal corresponding to the ambient temperature is obtained.
In other embodiments, the counting module 150 may also convert the pulse width t of the first level signal 1 First counting result N 1 And the pulse width t of the second first level signal 2 Second counting result N of 2 Output to the processor 160 so that the processor 160 can base on the first counting result N 1 And a second counting result N 2 And a digital signal of the ambient temperature is obtained.
In particular, the clock frequency of the clock signal generated by the field clock recovery module 120 may be assumed to be t clk Then:
first charging time = N 1 *t clk (6)，
Second charging time = N 2 *t clk (7)。
Since the first charging time is equal to the pulse width t of the first level signal 1 The second charging time is equal to the pulse width t of the second first level signal 2 Then:
t 1 ＝N 1 *t clk (8)，
t 2 ＝N 2 *t clk (9)。
substituting formula (8) into formula (4), substituting formula (9) into formula (5), and substituting formula (4) and formula (5) into formula (1) again can obtain the temperature voltage signal:
finally, substituting equation (10) into equation (2) yields the ambient temperature:
the kelvin temperature coefficient a may be obtained based on device characteristics of the temperature detection module 130 itself, and the conversion coefficient α proportional to the absolute temperature voltage signal and complementary to the absolute temperature voltage signal is a parameter of common knowledge in the art and may be obtained by a conventional technical means in the art, and B is-273.
With the above technical solution, the processor 160 may be based on the first counting result N 1 And a second counting result N 2 And a digital signal of the ambient temperature T is obtained.
In some alternative embodiments, the counting module 150 and the processor 160 may be combined into a digital circuit module. The specific implementation process can be realized by adopting the conventional technical means in the field, and the detailed description is omitted.
The embodiment of the invention also provides a passive radio frequency tag.
The passive radio frequency tag comprises the digital temperature sensor provided by the embodiment of the invention.
In a specific implementation, other functional modules except for the digital temperature sensor in the passive radio frequency tag can share the radio frequency induction module and the field clock recovery module with the digital temperature sensor.
While specific embodiments of the present examples have been described above, these embodiments are not intended to limit the scope of the present disclosure, even if only a single embodiment is described with respect to a particular feature. The characteristic examples provided in the embodiments of the present invention are intended to be illustrative, not limiting, unless differently expressed. In particular implementations, the features of one or more dependent claims may be combined with the features of the independent claims in any suitable manner, depending on the practical requirements, and the features from the respective independent claims may be combined, not merely by the specific combinations enumerated in the claims.
Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (12)
1. A digital temperature sensor, comprising:
the radio frequency induction module is used for inducing a radio frequency signal generated by active radio frequency equipment;
the field clock recovery module is connected with the radio frequency induction module and used for generating a clock signal based on the radio frequency signal;
a temperature detection module to detect an ambient temperature and generate a voltage signal related to the ambient temperature;
the signal conversion module is connected with the temperature detection module and used for converting the voltage signal into a pulse signal related to the environment temperature;
and the counting module is respectively connected with the field clock recovery module and the signal conversion module and used for counting the pulse signals based on the clock signals so as to obtain counting results.
2. The digital temperature sensor of claim 1, wherein the radio frequency sensing module comprises an NFC sensing module.
3. The digital temperature sensor of claim 1, wherein the field clock recovery module comprises an inverter cascade circuit, a latch circuit, or a comparison generation circuit.
4. The digital temperature sensor of claim 1, wherein the temperature detection module comprises a bipolar transistor temperature sensor, a metal oxide semiconductor field effect transistor temperature sensor, or a resistive temperature sensor.
5. The digital temperature sensor of claim 1, wherein the signal conversion module comprises a ramp signal generator and a comparator; the ramp signal generator is used for generating a ramp signal; the comparator is respectively connected with the temperature detection module and the ramp signal generator, and is used for receiving and comparing the voltage signal and the ramp signal, and generating and outputting the pulse signal based on the comparison result.
6. The digital temperature sensor of claim 5, wherein the ramp signal generator is coupled to the temperature detection module to generate the ramp signal based on the voltage signal.
7. The digital temperature sensor of claim 6, wherein the ramp signal increases with time and stops when the voltage signal is increased.
8. The digital temperature sensor of claim 7, wherein the comparator is configured to generate a first level signal of the pulse signal when the ramp signal is less than or equal to the voltage signal.
9. The digital temperature sensor of claim 8, wherein the comparator is configured to flip the pulse signal from the first level signal to a second level signal when the ramp signal is stopped.
10. The digital temperature sensor according to claim 8, wherein the counting module is configured to count the first level signal to obtain a count result of the first level signal.
11. The digital temperature sensor of claim 10, comprising a processor coupled to the counting module to derive the digital signal based on the counting result.
12. A passive radio frequency tag comprising a digital temperature sensor according to any of claims 1 to 11.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202110342264.5A CN115146747A (en) | 2021-03-30 | 2021-03-30 | Digital temperature sensor and passive radio frequency tag comprising same |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102831457A (en) * | 2012-08-24 | 2012-12-19 | 广州中盈物流科讯有限公司 | Passive RFID ((Radio Frequency Identification Device) temperature sensor label |
| CN108955923A (en) * | 2018-06-28 | 2018-12-07 | 中国电子科技集团公司第二十四研究所 | Digital temperature sensor based on sigma-delta ADC |
| CN110138341A (en) * | 2018-02-02 | 2019-08-16 | 上海复旦微电子集团股份有限公司 | A kind of signal demodulating circuit |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102831457A (en) * | 2012-08-24 | 2012-12-19 | 广州中盈物流科讯有限公司 | Passive RFID ((Radio Frequency Identification Device) temperature sensor label |
| CN110138341A (en) * | 2018-02-02 | 2019-08-16 | 上海复旦微电子集团股份有限公司 | A kind of signal demodulating circuit |
| CN108955923A (en) * | 2018-06-28 | 2018-12-07 | 中国电子科技集团公司第二十四研究所 | Digital temperature sensor based on sigma-delta ADC |
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