Demodulation circuit and passive internet of things tag chip

Abstract

The invention discloses a demodulation circuit and a passive internet of things tag chip. The demodulation circuit comprises an antenna, an envelope signal acquisition module, an amplification module, a configuration adjustment module and a comparison output module. The envelope signal acquisition module is connected with the antenna and is used for outputting a baseband envelope signal according to a carrier signal of the antenna; the amplification module is connected with the envelope signal acquisition module, and the amplification module is used for amplifying the baseband envelope signal and outputting a first amplification signal; the configuration adjusting module receives a configuration signal, the configuration adjusting module is connected with the amplification module, the configuration adjusting module is used for adjusting the first amplification signal according to the configuration signal and outputting a second amplification signal, and the second amplification signal is equal to the first amplification signal or meets the first amplification signal of a preset multiple; the comparison output module outputs a digital signal according to the second amplified signal. The demodulation circuit provided by the invention can be compatible with a radio frequency power supply mode and other environment energy power supply modes.

Description

Technical Field

[0001] The present invention relates to the field of passive communication technology, and in particular to a demodulation circuit and a passive Internet of Things tag chip. Background Art

[0002] Under the policy guidance of the dual carbon goals, passive Internet of Things technology has gradually become an important part of the 5G-A communication system. It requires that communication terminals cannot use batteries and can only obtain energy from the environment to power terminal devices. Environmental energy such as light energy, temperature difference energy, radio frequency energy, mechanical energy, etc.

[0003] Currently, passive IoT devices are classified into Class A and Class B. Class A refers to tags with pure RF functions, with a demodulation sensitivity of around -35dbm and a power consumption budget of several uW. Class B refers to tags that can be powered by other modes, with a demodulation sensitivity of around -45dbm and a power consumption budget of tens of uW. Since the demodulation sensitivities required for these two tags are different, the design of the demodulation circuit is different, which means that it is difficult for Class A and Class B tag chips to be compatible into one chip, which will increase the cost of operation and control from the perspective of chip manufacturers. Summary of the invention

[0004] The present invention provides a demodulation circuit and a passive Internet of Things tag chip to solve the problem that the demodulation circuit in the prior art is not compatible with a radio frequency power supply mode and other environmental energy power supply modes.

[0005] According to one aspect of the present invention, there is provided a demodulation circuit, comprising an antenna, an envelope signal acquisition module, an amplification module, a configuration adjustment module and a comparison output module;

[0006] The antenna is used to receive a carrier signal;

[0007] The envelope signal acquisition module is connected to the antenna, and the envelope signal acquisition module is used to output a baseband envelope signal according to the carrier signal of the antenna;

[0008] The amplification module is connected to the envelope signal acquisition module, and is used to amplify the baseband envelope signal by a first preset multiple and output a first amplified signal;

[0009] The configuration adjustment module receives a configuration signal, the configuration adjustment module is connected to the amplification module, and the configuration adjustment module is used to adjust the first amplified signal according to the configuration signal and output a second amplified signal, wherein the second amplified signal is equal to the first amplified signal, or satisfies a second preset multiple of the first amplified signal;

[0010] The comparison output module is connected to the configuration adjustment module, and the comparison output module is used to output a digital signal according to the second amplified signal.

[0011] Optionally, the amplification module includes a first operational amplifier and a first amplification factor adjustment unit, the positive input terminal of the first operational amplifier is connected to the output terminal of the envelope signal acquisition module, the negative input terminal of the first operational amplifier is connected to the first amplification factor adjustment unit, the output terminal of the first operational amplifier is connected to the output terminal of the amplification module, the first operational amplifier is used to amplify the baseband envelope signal, and the first amplification factor adjustment unit is used to adjust the amplification factor of the first operational amplifier so that the first operational amplifier outputs the first amplified signal.

[0012] Optionally, the first amplification factor adjustment unit includes a first resistor, a second resistor and a first capacitor, the first end of the first resistor and the first end of the second resistor are connected to the negative input terminal of the first operational amplifier, the second end of the first resistor is connected to the first end of the first capacitor, the second end of the second resistor is connected to the output terminal of the first operational amplifier, and the second end of the first capacitor is grounded.

[0013] Optionally, the carrier signal is a carrier signal with signaling modulation, and the product of the resistance value of the first resistor and the capacitance value of the first capacitor is greater than the inverse of the fundamental frequency of the signaling.

[0014] Optionally, the configuration adjustment module includes a second operational amplifier, a switch and a second amplification factor adjustment unit; the positive input terminal of the second operational amplifier is connected to the output terminal of the amplification module, the negative input terminal of the second operational amplifier is connected to the switch and the second amplification factor adjustment unit, the output terminal of the second operational amplifier is connected to the output terminal of the configuration adjustment module, the switch is connected in series to the second amplification factor adjustment unit, the second operational amplifier is used to amplify the first amplified signal, the second amplification factor adjustment unit is used to adjust the amplification factor of the second operational amplifier so that the second operational amplifier outputs the second amplified signal, and the switch is used to receive the configuration signal and be turned on or off according to the configuration signal.

[0015] Optionally, the second amplification factor adjustment unit includes a third resistor, a fourth resistor and a second capacitor, a first end of the third resistor and a first end of the switch, a second end of the switch is connected to the first end of the fourth resistor, a second end of the third resistor is connected to the first end of the second capacitor, a second end of the fourth resistor is connected to the output end of the second operational amplifier, and a second end of the second capacitor is grounded.

[0016] Optionally, the carrier signal is a carrier signal with signaling modulation, and the product of the resistance value of the third resistor and the capacitance value of the second capacitor is greater than the inverse of the fundamental frequency of the signaling.

[0017] Optionally, the comparison output module includes a comparison unit and a reference signal acquisition unit, the reference signal acquisition unit is connected to the output end of the configuration adjustment module, the reference signal acquisition unit is used to output the reference signal after filtering the second amplified signal, the first input end of the comparison unit is connected to the output end of the configuration adjustment module, the second input end of the comparison unit is connected to the output end of the reference signal acquisition unit, and the comparison unit is used to output the digital signal according to the second amplified signal and the reference signal.

[0018] Optionally, the comparison unit includes a comparator, the positive input of the comparator is connected to the first input of the comparison unit, the negative input of the comparator is connected to the second input of the comparison unit, and the output of the comparator is connected to the output of the comparison unit; the reference signal acquisition unit includes a fifth resistor and a third capacitor, the first end of the fifth resistor is connected to the output of the configuration adjustment module, the second end of the fifth resistor is connected to the negative input of the comparator and the first end of the third capacitor, and the second end of the third capacitor is grounded.

[0019] According to another aspect of the present invention, a passive Internet of Things tag chip is provided, comprising the demodulation circuit.

[0020] The technical solution of the embodiment of the present invention provides a demodulation circuit, including an antenna, an envelope signal acquisition module, an amplification module, a configuration adjustment module and a comparison output module; the envelope signal acquisition module is connected to the antenna, and the envelope signal acquisition module outputs a baseband envelope signal according to the carrier signal of the antenna; the amplification module amplifies the baseband envelope signal and outputs a first amplified signal, the configuration adjustment module receives the configuration signal, the configuration adjustment module is connected to the amplification module, the configuration adjustment module is used to adjust the first amplified signal according to the configuration signal, and output a second amplified signal, and the comparison output module outputs a digital signal according to the second amplified signal. Wherein, the second amplified signal is equal to the first amplified signal (meeting the amplification requirements of the pure RF power supply mode), or, meets the preset multiple of the first amplified signal (meeting the amplification requirements of other environmental power supply modes), that is, the demodulation circuit provided by the present invention can be compatible with the RF power supply mode and other environmental power supply modes, so that the Class A tag chip of the pure RF power supply mode and the Class B tag chip of the other environmental power supply mode can be compatible on one chip, which solves the problem that the demodulation circuit in the prior art cannot be compatible with the RF power supply mode and other environmental power supply modes.

[0021] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 is a structural schematic diagram of a demodulation circuit provided by an embodiment of the present invention;

[0024] Figure 2 is a circuit diagram of a demodulation circuit provided by an embodiment of the present invention;

[0025] Figure 3 It is a schematic diagram of the structure of a passive Internet of Things tag chip provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0027] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0028] An embodiment of the present invention provides a demodulation circuit. Figure 1 is a schematic diagram of a demodulation circuit provided by an embodiment of the present invention, such as Figure 1As shown, the demodulation circuit 100 includes an antenna A, an envelope signal acquisition module 110, an amplification module 120, a configuration adjustment module 130 and a comparison output module 140; the antenna A is used to receive a carrier signal; the envelope signal acquisition module 110 is connected to the antenna A, and the envelope signal acquisition module 110 is used to output a baseband envelope signal according to the carrier signal of the antenna A; the amplification module 120 is connected to the envelope signal acquisition module 110, and the amplification module 120 is used to amplify the baseband envelope signal by a first preset multiple and output a first amplified signal; the configuration adjustment module 130 receives a configuration signal, the configuration adjustment module 130 is connected to the amplification module 120, and the configuration adjustment module 130 is used to adjust the first amplified signal according to the configuration signal and output a second amplified signal, wherein the second amplified signal is equal to the first amplified signal, or satisfies the first amplified signal of the second preset multiple; the comparison output module 140 is connected to the configuration adjustment module 130, and the comparison output module 140 is used to output a digital signal according to the second amplified signal.

[0029] In this embodiment, the demodulation circuit 100 is a circuit that restores the modulated signal to the original signal, and can recover the original digital signal from the modulated signal carrying information. Antenna A is a device that transmits and receives electromagnetic waves and is a key component for realizing radio communication. The envelope signal acquisition module 110 is a module that extracts the baseband envelope signal from the complex modulated signal. The baseband envelope signal refers to the amplitude change of the original electrical signal that has not been modulated. By acquiring the baseband envelope signal, the quality and reliability of signal transmission can be improved. For example, the envelope signal acquisition module 110 includes an envelope detector. The amplification module 120 is a module that amplifies the baseband envelope signal. The configuration adjustment module 130 is a module that adjusts the first amplified signal according to the configuration signal. The configuration signal can be a "0, 1" logic signal. The comparison output module 140 is a module that outputs a digital signal after comparing the second amplified signal with the reference signal. For example, the comparison output module 140 includes a comparator.

[0030] In this embodiment, antenna A receives a carrier with signaling modulation sent by a cellular base station, the envelope signal acquisition module 110 extracts the carrier signal of antenna A and outputs a baseband envelope signal, the amplification module 120 amplifies the baseband envelope signal and outputs a first amplified signal, the configuration adjustment module 130 adjusts the first amplified signal according to the configuration signal, and outputs a second amplified signal, for example, when the configuration signal is logic "0", the second amplified signal output by the configuration adjustment module 130 is equal to the first amplified signal, when the configuration signal is logic "1", the second amplified signal output by the configuration adjustment module 130 is equal to the first amplified signal of a preset multiple, and the comparison output module 140 outputs a digital signal by comparing the second amplified signal with the reference signal. The configuration adjustment module 130 can achieve different amplification requirements of the demodulation circuit by adjusting the first amplified signal.

[0031] The technical solution of this embodiment provides a demodulation circuit, including an antenna, an envelope signal acquisition module, an amplification module, a configuration adjustment module and a comparison output module; the envelope signal acquisition module is connected to the antenna, and the envelope signal acquisition module outputs a baseband envelope signal according to the carrier signal of the antenna; the amplification module amplifies the baseband envelope signal and outputs a first amplified signal, the configuration adjustment module receives the configuration signal, the configuration adjustment module is connected to the amplification module, the configuration adjustment module is used to adjust the first amplified signal according to the configuration signal, and output a second amplified signal, and the comparison output module outputs a digital signal according to the second amplified signal. Among them, the second amplified signal is equal to the first amplified signal (meeting the amplification requirements of the pure RF power supply mode), or, meets the preset multiple of the first amplified signal (meeting the amplification requirements of other environmental power supply modes), that is, the demodulation circuit provided by the present invention can be compatible with the RF power supply mode and other environmental power supply modes, so that the Class A tag chip of the pure RF power supply mode and the Class B tag chip of the other environmental power supply mode can be compatible on one chip, which solves the problem that the demodulation circuit in the prior art cannot be compatible with the RF power supply mode and other environmental power supply modes.

[0032] Figure 2 is a circuit diagram of a demodulation circuit provided by an embodiment of the present invention, such as Figure 2 As shown, the amplification module 120 includes a first operational amplifier U1 and a first amplification factor adjustment unit 210, the positive input terminal of the first operational amplifier U1 is connected to the output terminal of the envelope signal acquisition module 110, the negative input terminal of the first operational amplifier U1 is connected to the first amplification factor adjustment unit 210, the output terminal of the first operational amplifier U1 is connected to the output terminal of the amplification module 120, the first operational amplifier U1 is used to amplify the baseband envelope signal, and the first amplification factor adjustment unit 210 is used to adjust the amplification factor of the first operational amplifier U1 so that the first operational amplifier U1 outputs a first amplified signal.

[0033] In this embodiment, the first amplification factor adjustment unit 210 is a unit for adjusting the amplification factor of the first operational amplifier U1. The demodulation sensitivity of passive IoT tag chips in Class A pure RF power supply mode and Class B other environmental power supply mode is at least 10db higher than that of ordinary RF tag chips. Therefore, the signal amplitude output by the envelope detector alone is not enough to be directly connected to the comparison output module for comparison. The baseband needs to be amplified to about 100mV to pass the comparison module for anti-noise interference. Exemplarily, the demodulation circuit in the passive IoT tag chip in Class A pure RF power supply mode needs to be amplified a times, and the first amplification factor adjustment unit 210 adjusts the amplification factor of the first operational amplifier U1 to a, that is, the first amplified signal is a times the baseband envelope signal.

[0034] Specifically, the first amplification factor adjustment unit 210 includes a first resistor R1, a second resistor R2 and a first capacitor C1, wherein the first end of the first resistor R1 and the first end of the second resistor R2 are connected to the negative input end of the first operational amplifier U1, the second end of the first resistor R1 is connected to the first end of the first capacitor C1, the second end of the second resistor R2 is connected to the output end of the first operational amplifier U1, and the second end of the first capacitor C1 is grounded. The carrier signal is a carrier signal with signaling modulation, and the product of the resistance value of the first resistor R1 and the capacitance value of the first capacitor C1 is greater than the inverse of the fundamental frequency of the signaling.

[0035] On the basis of the above embodiment, the first gain adjustment unit 210 adjusts the gain of the first operational amplifier U1 to a, that is, by setting the parameters of the first resistor R1 and the second resistor R2, R2 / R1=a. Since 1 / (R1*C1) is the high-pass cutoff frequency of the amplification module 120, the product R1*C1 of the resistance value of the first resistor R1 and the capacitance value of the first capacitor C1 is set to be much larger than the inverse of the baseband frequency of the signaling, so that the cutoff frequency is much smaller than the signal frequency to be amplified, which can ensure that the signal amplified by the amplification module 120 is not distorted.

[0036] Continue to refer Figure 2 The configuration adjustment module 130 includes a second operational amplifier U2, a switch S and a second amplification factor adjustment unit 220; the positive input end of the second operational amplifier U2 is connected to the output end of the amplification module 120, the negative input end of the second operational amplifier U2 is connected to the switch S and the second amplification factor adjustment unit 220, the output end of the second operational amplifier U2 is connected to the output end of the configuration adjustment module 130, the switch S is connected in series to the second amplification factor adjustment unit 220, the second operational amplifier U2 is used to amplify the first amplified signal, the second amplification factor adjustment unit 220 is used to adjust the amplification factor of the second operational amplifier U2 so that the second operational amplifier U2 outputs a second amplified signal, and the switch S is used to receive a configuration signal and be turned on or off according to the configuration signal.

[0037] In this embodiment, the second amplification factor adjustment unit 220 is a unit for adjusting the amplification factor of the second operational amplifier U2. For example, the demodulation circuit in the passive IoT tag chip of the Class B other environment power supply mode needs to be amplified by b times. On the basis of the above embodiment, when the configuration signal is logic "0", the switch S is disconnected, the amplification factor of the second operational amplifier U2 is 1, and the second amplified signal output by the second operational amplifier U2 is equal to the first amplified signal. At this time, the second amplified signal is a times the baseband envelope signal, and the amplification factor of the demodulation circuit meets the amplification requirements of the Class A pure RF power supply mode. When the configuration signal is logic "1", the switch S is turned on, and the second amplification factor adjustment unit 220 adjusts the amplification factor of the second operational amplifier U2 to b / a, and the second amplified signal output by the second operational amplifier U2 is b / a times the first amplified signal. At this time, the second amplified signal is b times the baseband envelope signal, and the amplification factor of the demodulation circuit meets the amplification requirements of the Class B other environment power supply mode.

[0038] Specifically, the second amplification factor adjustment unit 220 includes a third resistor R3, a fourth resistor R4, and a second capacitor C2, a first end of the third resistor R3 and a first end of a switch S, a second end of the switch S connected to a first end of the fourth resistor R4, a second end of the third resistor R3 connected to a first end of the second capacitor C2, a second end of the fourth resistor R4 connected to an output end of the second operational amplifier U2, and a second end of the second capacitor C2 connected to ground. The product of the resistance value of the third resistor R3 and the capacitance value of the second capacitor C2 is greater than the inverse of the fundamental frequency of the signaling.

[0039] On the basis of the above embodiment, when the switch S is disconnected, the second amplification factor adjustment unit 220 cannot adjust the amplification factor of the second operational amplifier U2, the second operational amplifier U2 and the fourth resistor R4 form a unit gain buffer, and the amplification factor of the second operational amplifier U2 is 1. At this time, the amplification factor of the demodulation circuit meets the amplification requirements of the Class A pure RF power supply mode. When the switch S is closed, the second amplification factor adjustment unit 220 adjusts the amplification factor of the second operational amplifier U2 to b / a by setting the resistance values ​​of the third resistor R3 and the fourth resistor R4, that is, R4 / R3=b / a, and the second amplified signal output by the second operational amplifier U2 is b / a times the first amplified signal. At this time, the amplification factor of the demodulation circuit meets the amplification requirements of the Class B other environment power supply mode. Since 1 / (R3*C2) is the high-pass cutoff frequency of the configuration adjustment module 130, the product R3*C2 of the resistance value of the third resistor R3 and the capacitance value of the second capacitor C2 is set to be much larger than the inverse of the baseband frequency of the signaling, so that the cutoff frequency is much smaller than the signal frequency to be amplified, which can ensure that the signal amplified by the configuration adjustment module 130 is not distorted. The DC points of the input and output of the first operational amplifier U1 and the second operational amplifier U2 are the same, and the DC point voltage can be set at half of the operational amplifier power supply voltage, so that the operational amplifier can work at the optimal DC point and have the largest upper and lower output swings.

[0040] Continue to refer Figure 2 The comparison output module 140 includes a comparison unit 230 and a reference signal acquisition unit 240. The reference signal acquisition unit 240 is connected to the output end of the configuration adjustment module 130. The reference signal acquisition unit 240 is used to output a reference signal after filtering the second amplified signal. The first input end of the comparison unit 230 is connected to the output end of the configuration adjustment module 130. The second input end of the comparison unit 230 is connected to the output end of the reference signal acquisition unit 240. The comparison unit 230 is used to output a digital signal according to the second amplified signal and the reference signal. The reference signal acquisition unit 240 is a unit for acquiring a reference signal according to the second amplified signal, and the comparison unit 230 is a unit for outputting a digital signal after comparing the second amplified signal with the reference signal. The reference signal is the average value of the second amplified signal.

[0041] Specifically, the comparison unit 230 includes a comparator U3, a positive input terminal of the comparator U3 is connected to a first input terminal of the comparison unit 230, a negative input terminal of the comparator U3 is connected to a second input terminal of the comparison unit 230, and an output terminal of the comparator U3 is connected to an output terminal of the comparison unit 230; the reference signal acquisition unit 240 includes a fifth resistor R5 and a third capacitor C3, a first end of the fifth resistor R5 is connected to an output terminal of the configuration adjustment module 130, a second end of the fifth resistor R5 is connected to a negative input terminal of the comparator U3 and a first end of the third capacitor C3, and a second end of the third capacitor C3 is grounded.

[0042] In this embodiment, the fifth resistor R5 and the third capacitor C3 form a low-pass filter, the second amplified signal is processed by low-pass filtering and then outputs a reference signal, the cut-off frequency of the low-pass filter formed by the fifth resistor R5 and the third capacitor C3 is negatively correlated with the product R5*C3 of the fifth resistor R5 and the third capacitor C3, and the value of R5*C3 is set to be greater than 1 / several times of the signaling baseband frequency, which can improve the anti-noise performance. In combination with the above embodiments, the value of each resistor cannot be too large to avoid occupying a large chip area and causing a large parasitic capacitance.

[0043] The embodiment of the present invention also provides a passive Internet of Things tag chip, Figure 3 is a schematic diagram of the structure of a passive Internet of Things tag chip provided by an embodiment of the present invention, such as Figure 3 As shown, the passive Internet of Things tag chip 10 includes the demodulation circuit 100 in any of the above embodiments.

[0044] In this embodiment, the passive IoT tag chip 10 is a radio frequency identification tag chip that does not require external power supply. It requires that the communication terminal cannot use batteries and can only obtain energy from the environment to power the terminal device. Environmental energy is such as light energy, temperature difference energy, radio frequency energy, mechanical energy, etc. Referring to the above embodiment, the demodulation circuit 100 adjusts the first amplified signal by configuring the adjustment module 130 to achieve different amplification requirements of the demodulation circuit, which not only meets the amplification requirements of the Class A pure radio frequency power supply mode, but also meets the amplification requirements of the Class B other environmental energy power supply mode. Applying the demodulation circuit 100 to the passive IoT tag chip 10 can make the passive IoT tag chip 10 compatible with both Class A tag chips and Class B tag chips, reducing the operation and control costs during the chip production process.

[0045] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0046] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A demodulation circuit, characterized in that: It includes an antenna, an envelope signal acquisition module, an amplification module, a configuration adjustment module and a comparison output module; The antenna is used to receive a carrier signal; The envelope signal acquisition module is connected to the antenna, and the envelope signal acquisition module is used to output a baseband envelope signal according to the carrier signal of the antenna; The amplification module is connected to the envelope signal acquisition module, and is used to amplify the baseband envelope signal by a first preset multiple and output a first amplified signal; The configuration adjustment module receives a configuration signal, the configuration adjustment module is connected to the amplification module, and the configuration adjustment module is used to adjust the first amplified signal according to the configuration signal and output a second amplified signal, wherein the second amplified signal is equal to the first amplified signal, or satisfies a second preset multiple of the first amplified signal; The comparison output module is connected to the configuration adjustment module, and the comparison output module is used to output a digital signal according to the second amplified signal.

2. The demodulation circuit according to claim 1, characterized in that: The amplification module includes a first operational amplifier and a first amplification factor adjustment unit, the positive input end of the first operational amplifier is connected to the output end of the envelope signal acquisition module, the negative input end of the first operational amplifier is connected to the first amplification factor adjustment unit, the output end of the first operational amplifier is connected to the output end of the amplification module, the first operational amplifier is used to amplify the baseband envelope signal, and the first amplification factor adjustment unit is used to adjust the amplification factor of the first operational amplifier so that the first operational amplifier outputs the first amplified signal.

3. The demodulation circuit according to claim 2, characterized in that: The first amplification factor adjustment unit includes a first resistor, a second resistor and a first capacitor, the first end of the first resistor and the first end of the second resistor are connected to the negative input terminal of the first operational amplifier, the second end of the first resistor is connected to the first end of the first capacitor, the second end of the second resistor is connected to the output terminal of the first operational amplifier, and the second end of the first capacitor is grounded.

4. The demodulation circuit according to claim 3, characterized in that: The carrier signal is a carrier signal with signaling modulation, and the product of the resistance value of the first resistor and the capacitance value of the first capacitor is greater than the inverse of the fundamental frequency of the signaling.

5. The demodulation circuit according to claim 1, characterized in that: The configuration adjustment module includes a second operational amplifier, a switch and a second amplification factor adjustment unit; the positive input end of the second operational amplifier is connected to the output end of the amplification module, the negative input end of the second operational amplifier is connected to the switch and the second amplification factor adjustment unit, the output end of the second operational amplifier is connected to the output end of the configuration adjustment module, the switch is connected in series to the second amplification factor adjustment unit, the second operational amplifier is used to amplify the first amplified signal, the second amplification factor adjustment unit is used to adjust the amplification factor of the second operational amplifier so that the second operational amplifier outputs the second amplified signal, and the switch is used to receive the configuration signal and be turned on or off according to the configuration signal.

6. The demodulation circuit according to claim 5, characterized in that: The second amplification factor adjustment unit includes a third resistor, a fourth resistor and a second capacitor, a first end of the third resistor and a first end of the switch, a second end of the switch connected to the first end of the fourth resistor, a second end of the third resistor connected to the first end of the second capacitor, a second end of the fourth resistor connected to the output end of the second operational amplifier, and a second end of the second capacitor is grounded.

7. The demodulation circuit according to claim 6, characterized in that: The carrier signal is a carrier signal with signaling modulation, and the product of the resistance value of the third resistor and the capacitance value of the second capacitor is greater than the inverse of the fundamental frequency of the signaling.

8. The demodulation circuit according to claim 1, characterized in that: The comparison output module includes a comparison unit and a reference signal acquisition unit, the reference signal acquisition unit is connected to the output end of the configuration adjustment module, the reference signal acquisition unit is used to output the reference signal after filtering the second amplified signal, the first input end of the comparison unit is connected to the output end of the configuration adjustment module, the second input end of the comparison unit is connected to the output end of the reference signal acquisition unit, and the comparison unit is used to output the digital signal according to the second amplified signal and the reference signal.

9. The demodulation circuit according to claim 8, characterized in that: The comparison unit comprises a comparator, wherein a positive input terminal of the comparator is connected to a first input terminal of the comparison unit, a negative input terminal of the comparator is connected to a second input terminal of the comparison unit, and an output terminal of the comparator is connected to an output terminal of the comparison unit; The reference signal acquisition unit includes a fifth resistor and a third capacitor, the first end of the fifth resistor is connected to the output end of the configuration adjustment module, the second end of the fifth resistor is connected to the negative input end of the comparator and the first end of the third capacitor, and the second end of the third capacitor is grounded.

10. A passive Internet of Things tag chip, characterized in that: A demodulation circuit comprising any one of claims 1 to 9.

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