CN110852121A - Novel non-contact transponder receiving circuit - Google Patents
Novel non-contact transponder receiving circuit Download PDFInfo
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- CN110852121A CN110852121A CN201810947110.7A CN201810947110A CN110852121A CN 110852121 A CN110852121 A CN 110852121A CN 201810947110 A CN201810947110 A CN 201810947110A CN 110852121 A CN110852121 A CN 110852121A
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- comparator
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- nmos transistor
- receiving circuit
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- 239000003990 capacitor Substances 0.000 claims abstract description 73
- 230000010354 integration Effects 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 6
- 230000005540 biological transmission Effects 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 238000013461 design Methods 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- 239000000470 constituent Substances 0.000 description 2
- 230000006698 induction Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
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- 230000004048 modification Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
- G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
- G06K7/10009—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
- G06K7/10297—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves arrangements for handling protocols designed for non-contact record carriers such as RFIDs NFCs, e.g. ISO/IEC 14443 and 18092
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
- G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
- G06K7/10009—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
- G06K7/10316—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves using at least one antenna particularly designed for interrogating the wireless record carriers
- G06K7/10336—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves using at least one antenna particularly designed for interrogating the wireless record carriers the antenna being of the near field type, inductive coil
Abstract
The invention provides a novel non-contact transponder receiving circuit, which comprises a resonance circuit and a demodulation circuit, wherein the resonance circuit comprises a first inductor and a first capacitor, one end of the first inductor is connected with one end of the first capacitor, and the other end of the first inductor is connected with the other end of the first capacitor; the demodulation circuit comprises a resistor, a first NMOS transistor, a second NMOS transistor, a third NMOS transistor, a fourth NMOS transistor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a first comparator, a second comparator, a third comparator, a fourth comparator and a first hysteresis comparator. The demodulation circuit of the invention introduces the second comparator and the fourth comparator, increases the driving capability of recovering subcarrier signals, and reduces the interference of high-frequency signals; in addition, the receiving circuit of the invention has simple structure, easy integration and stable output signal of the hysteresis comparator.
Description
Technical Field
The invention relates to the technical field of non-contact transponders in the radio frequency identification technology, in particular to a novel receiving circuit of a non-contact transponder.
Background
The Radio frequency identification technology is a non-contact automatic identification technology (RFID), and its basic principle is to transmit data between a reader and a transponder by using Radio frequency signals to realize target identification and information exchange. In recent years, the ISO IEC 14443 standard transponder has been rapidly popularized and popularized in many service fields, such as goods procurement and distribution, biological manufacturing, public transportation, commercial trade, and logistics tracking, all of which do not depart from the rapidity, safety, and low cost of data transmission of transponders and readers. The non-contact transponder and the reader-writer need to carry out data transmission, the non-contact transponder needs to be provided with a corresponding receiving circuit, the receiving circuit is a key circuit in the 13.56MHz non-contact transponder and is related to the data transmission performance of the non-contact transponder and the reader-writer, and the performance of the receiving circuit is directly related to whether the non-contact transponder can accurately answer an instruction sent by the reader-writer. Therefore, the design and research of the receiving circuit of the non-contact transponder have very important significance.
Referring to fig. 1, a diagram of a receiving circuit of a contactless transponder commonly used at present is shown, and its working principle is as follows: the non-contact transponder induction antenna L1 captures a ground carrier signal emitted by the reader antenna, when the reader sends a subcarrier signal, the subcarrier signal is recovered through a detection circuit composed of a first NMOS transistor NM1, a second NMOS transistor NM2, a first resistor R1, a second capacitor C2 and a third capacitor C3 and input to the positive input end of a hysteresis comparator COMP, a direct current offset value VREF is provided for the subcarrier signal by a second resistor R2, the recovered subcarrier signal is compared with VREF by the hysteresis comparator COMP and then outputs a subcarrier digital signal VOUT, and after the subcarrier digital signal VOUT is correctly decoded by the digital circuit, the non-contact transponder can give a corresponding answer to the reader.
The contactless transponder receiving circuit described above has some drawbacks:
1. the amplitude of the subcarrier signal voltage restored by the detection circuit composed of the first NMOS transistor NM1, the second NMOS transistor NM2, the first resistor R1, the second capacitor C2, and the third capacitor C3 may vary with the field strength, making the determination threshold of the hysteresis comparator COMP difficult to design.
2. Because the modulation factor variation is large when the reader-writer transmits the subcarriers with high rate (such as 847.5 KBPS) and low rate (such as 106 KBPS), the traditional transponder receiving circuit is difficult to be compatible with the communication with high and low rates.
3. The dc voltage of the input signal of the hysteresis comparator COMP may be relatively high, so that the power supply of the hysteresis comparator COMP tends to be the transponder rectified output voltage, but the voltage of the transponder rectified output may be unstable, which may reduce the stability of the output signal of the hysteresis comparator COMP.
In view of the above problems, it is an object of the present invention to design a novel contactless transponder receiving circuit.
Disclosure of Invention
In view of the above-mentioned shortcomings in the prior art, an object of the present invention is to provide a novel receiving circuit of a contactless transponder, which includes a resonant circuit and a demodulation circuit, and can effectively improve the stability of the receiving circuit.
In order to achieve the technical purpose, the technical scheme adopted by the invention is as follows:
a novel non-contact transponder receiving circuit comprises a resonant circuit and a demodulation circuit, wherein the resonant circuit comprises a first inductor and a first capacitor, one end of the first inductor is connected with one end of the first capacitor, and the other end of the first inductor is connected with the other end of the first capacitor;
the demodulation circuit comprises a resistor, a first NMOS transistor, a second NMOS transistor, a third NMOS transistor, a fourth NMOS transistor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a first comparator, a second comparator, a third comparator, a fourth comparator and a first hysteresis comparator, wherein the grid end of the first NMOS transistor, the drain end of the second NMOS transistor, the grid end of the third NMOS transistor and the drain end of the third NMOS transistor are connected with one end of the resonant circuit, the grid end of the second NMOS transistor, the drain end of the first NMOS transistor, the grid end of the fourth NMOS transistor and the drain end of the fourth NMOS transistor are connected with the other end of the resonant circuit, the source end of the third NMOS transistor, the source end of the fourth NMOS transistor and one end of the second capacitor are connected with one end of the resistor, the other end of the second capacitor, one end of the third capacitor, the gate end of the fourth NMOS transistor, the drain end of the second NMOS transistor, the drain, One end of a fourth capacitor is connected with one end of a fifth capacitor, the source end of the first NMOS transistor, the source end of the second NMOS transistor, the other end of the resistor, the other end of the third capacitor, the one end grounding end of the sixth capacitor, the other end of the fourth capacitor, the negative input end of the first comparator, and the output end of the first comparator are connected with the positive input end of the second comparator, the other end of the fifth capacitor, the negative input end of the third comparator, and the output end of the third comparator are connected with the positive input end of the fourth comparator, the positive input end of the first comparator and the positive input end of the third comparator are connected with a reference voltage, the negative input end of the second comparator, the output end of the second comparator, and the positive input end of the hysteresis comparator, the negative input end of the fourth comparator, the output end of the hysteresis comparator, the negative input end of the hysteresis comparator, The other end of the sixth capacitor is connected, and the output end of the hysteresis comparator is an output signal.
Compared with the prior art, the novel non-contact transponder receiving circuit of the invention adopts the resonant circuit and the demodulation circuit structure, and has the following beneficial effects:
(1) the introduction of the fourth capacitor and the fifth capacitor in the demodulation circuit can prevent the direct current level on the antenna from being input to the negative input ends of the first comparator and the third comparator, thereby reducing the withstand voltage requirement of the first comparator and the third comparator on an input electric device.
(2) The introduction of the first comparator and the third comparator in the demodulation circuit provides a direct current bias value for the first comparator and the third comparator, and a resistor is not used for providing the direct current bias value, so that the area is reduced, and the cost of a current chip is reduced.
(3) The second comparator and the fourth comparator in the demodulation circuit are introduced, so that the driving capability of the recovered subcarrier signal is increased, and the interference of a high-frequency signal is reduced.
(4) The sixth capacitor in the demodulation circuit is introduced, so that the output signal of the fourth comparator is slower than that of the third comparator, and the difference of the two signals is used as the judgment threshold of the hysteresis comparator at the next stage.
(5) The receiving circuit of the invention can be compatible with high and low rate data transmission.
(6) The receiving circuit of the invention has simple structure, easy integration and stable output signal of the hysteresis comparator.
The invention is further described with reference to the following figures and detailed description.
Drawings
Fig. 1 is a block diagram of a receiving circuit of a conventional contactless transponder.
Fig. 2 is a block diagram of a novel contactless transponder receiving circuit embodying the present invention.
Fig. 3 is a schematic diagram of the operation of a novel contactless transponder receiving circuit embodying the present invention.
Detailed Description
The following detailed description of the present invention is provided in conjunction with the accompanying drawings, but it should be understood that the scope of the present invention is not limited to the specific embodiments.
Referring to fig. 2, a diagram of a contactless transponder receiving circuit is shown in accordance with an embodiment of the present invention. The novel non-contact transponder receiving circuit comprises a resonant circuit 101 and a demodulation circuit 102, wherein the resonant circuit comprises a first inductor L1 and a first capacitor C1, one end VA of the first inductor L1 is connected with one end of the first capacitor C1, and the other end VB of the first inductor L1 is connected with the other end VB of the first capacitor C1; the receiving circuit comprises a resistor R1, a first NMOS transistor NM1, a second NMOS transistor NM2, a third NMOS transistor NM3, a fourth NMOS transistor NM4, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, a first comparator COMP1, a second comparator COMP2, a third comparator COMP3, a fourth comparator COMP 53 and a first hysteresis comparator COMP0, wherein a gate terminal of the first NMOS transistor NM1, a drain terminal of the second NMOS transistor NM2, a gate terminal of the third NMOS transistor NM3, a drain terminal of the third NMOS transistor NM3 are connected with a VA terminal in the resonant circuit, a gate terminal of the second NMOS transistor NM3, a drain terminal of the first NMOS transistor NM3, an NM terminal of the fourth NMOS transistor NM3, a gate terminal of the fourth NMOS transistor NM3 and a drain terminal of the first NMOS transistor VB 3, a drain terminal of the NMOS transistor C3 and a drain terminal of the first NMOS transistor VB 3 are connected with a drain terminal of the NMOS transistor R363672, the other end of the second capacitor C2, one end of the third capacitor C3, one end of the fourth capacitor C4, one end of the fifth capacitor C5, the source end of the first NMOS transistor NM1, the source end of the second NMOS transistor NM2, the other end of the resistor R1, the other end of the third capacitor C3, one end ground terminal VSS of the sixth capacitor C6, the other end of the fourth capacitor C4, the negative input end of the first comparator COMP1, the output end of the first comparator COMP1, the positive input end of the second comparator COMP2, the other end of the fifth capacitor C5, the negative input end of the third comparator COMP3, the output end of the third comparator COMP3, and the positive input end of the fourth comparator COMP4, the positive input end of the first comparator C1, the positive input end of the third comparator COMP3, the negative input end of the second comparator COMP2, the positive input end of the second comparator COMP2, the positive input end of the comparator COMP0, and the comparator COMP0 as a hysteresis node COMP0, the negative input terminal of the fourth comparator COMP4, the output terminal of the fourth comparator COMP4, the negative input terminal of the hysteresis comparator COMP0, and the other terminal of the sixth capacitor C6 are connected to serve as a node SING _ SLOW, and the output terminal of the hysteresis comparator COMP0 is the output signal VOUT.
Referring to fig. 3, a schematic diagram of a novel contactless transponder receiving circuit embodying the present invention is shown. When the non-contact transponder receiving circuit works, the first inductor L1 of the non-contact transponder induction antenna captures a carrier signal transmitted by the reader/writer antenna, when the reader/writer transmits a subcarrier signal, the subcarrier signal is recovered by a detection circuit composed of a first NMOS transistor NM1, a second NMOS transistor NM2, a resistor R1, a second capacitor C2 and a third capacitor C3, the recovered subcarrier signal passes through the DC blocking action of a fourth capacitor C4 and a fifth capacitor C5, the first comparator COMP1 and the third comparator COMP3 provide a DC offset voltage VREF for the subcarrier signal, the first comparator COMP1 and the third comparator COMP3 are designed with low power consumption to prevent the distortion and attenuation of the output signal caused by too small output impedance, the subcarrier signal with the DC offset passes through the buffer action of the second comparator COMP2 and the fourth comparator COMP4, the driving capability becomes large, and the signal output by the fourth comparator COMP4 passes through the sixth capacitor C6 to change into a slow signal after passing through the second comparator COMP 6, for example, the SING _ SLOW signal in fig. 3, the positive input terminal of the hysteresis comparator COMP0 is a normal recovered subcarrier signal, and the difference between the SING _ SLOW and the SING signal in fig. 3 is used as the determination threshold of the hysteresis comparator COMP0, and the transponder gives a corresponding answer to the reader/writer after VOUT is correctly interpreted by the digital demodulation circuit.
As can be seen from the above, the novel contactless transponder receiving circuit according to the embodiment of the present invention can effectively improve the stability of the demodulation circuit and reduce the manufacturing cost through the resonant circuit 101 and the demodulation circuit 102.
The above embodiments are merely illustrative of the basic idea of the present invention, and the constituent circuits related to the present invention are not drawn in terms of the number of constituent circuits, shapes, arrangement of devices, and connection modes in actual implementation. The actual implementation of the method can be changed freely according to the type, number, connection mode, device arrangement mode and device parameters of each circuit.
The above-mentioned embodiments are only preferred embodiments of the present invention, and do not limit the extension of the technical solution of the present invention. Any modifications, equivalent changes and obvious changes of the known technology made by the technical proposal of the invention by the technical personnel in the field are all within the protection scope of the invention.
Claims (1)
1. A novel non-contact transponder receiving circuit is characterized by comprising a resonant circuit and a demodulation circuit, wherein the resonant circuit comprises a first inductor and a first capacitor, one end of the first inductor is connected with one end of the first capacitor, and the other end of the first inductor is connected with the other end of the first capacitor;
the demodulation circuit comprises a resistor, a first NMOS transistor, a second NMOS transistor, a third NMOS transistor, a fourth NMOS transistor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a first comparator, a second comparator, a third comparator, a fourth comparator and a first hysteresis comparator, wherein the grid end of the first NMOS transistor, the drain end of the second NMOS transistor, the grid end of the third NMOS transistor and the drain end of the third NMOS transistor are connected with one end of the resonant circuit, the grid end of the second NMOS transistor, the drain end of the first NMOS transistor, the grid end of the fourth NMOS transistor and the drain end of the fourth NMOS transistor are connected with the other end of the resonant circuit, the source end of the third NMOS transistor, the source end of the fourth NMOS transistor and one end of the second capacitor are connected with one end of the resistor, the other end of the second capacitor, one end of the third capacitor, the gate end of the fourth NMOS transistor, the drain end of the second NMOS transistor, the drain, One end of a fourth capacitor is connected with one end of a fifth capacitor, the source end of the first NMOS transistor, the source end of the second NMOS transistor, the other end of the resistor, the other end of the third capacitor, the one end grounding end of the sixth capacitor, the other end of the fourth capacitor, the negative input end of the first comparator, and the output end of the first comparator are connected with the positive input end of the second comparator, the other end of the fifth capacitor, the negative input end of the third comparator, and the output end of the third comparator are connected with the positive input end of the fourth comparator, the positive input end of the first comparator and the positive input end of the third comparator are connected with a reference voltage, the negative input end of the second comparator, the output end of the second comparator, and the positive input end of the hysteresis comparator, the negative input end of the fourth comparator, the output end of the hysteresis comparator, the negative input end of the hysteresis comparator, The other end of the sixth capacitor is connected, and the output end of the hysteresis comparator is an output signal.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201810947110.7A CN110852121A (en) | 2018-08-20 | 2018-08-20 | Novel non-contact transponder receiving circuit |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201810947110.7A CN110852121A (en) | 2018-08-20 | 2018-08-20 | Novel non-contact transponder receiving circuit |
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| CN110852121A true CN110852121A (en) | 2020-02-28 |
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| US20020172270A1 (en) * | 2001-05-21 | 2002-11-21 | Whikehart J. William | AM/FM/IBOC receiver architecture |
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| CN207166632U (en) * | 2017-09-19 | 2018-03-30 | 四川福润得数码科技有限责任公司 | A kind of antenna isolated location and isolation tune two-in-one die set |
| CN208636845U (en) * | 2018-08-20 | 2019-03-22 | 紫光同芯微电子有限公司 | Novel non-contact transponder receives circuit |
-
2018
- 2018-08-20 CN CN201810947110.7A patent/CN110852121A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20020172270A1 (en) * | 2001-05-21 | 2002-11-21 | Whikehart J. William | AM/FM/IBOC receiver architecture |
| US20030091183A1 (en) * | 2001-10-30 | 2003-05-15 | Integration Associates Inc. | Method and apparatus for isolation in a data access arrangement using analog encoded pulse signaling |
| CN103391261A (en) * | 2012-05-09 | 2013-11-13 | Nxp股份有限公司 | Equipment and method of capacitive isolated voltage domain communication |
| CN104392193A (en) * | 2014-11-12 | 2015-03-04 | 广州中大微电子有限公司 | Card reader and method for filtering received signals of RFID card reader |
| CN207166632U (en) * | 2017-09-19 | 2018-03-30 | 四川福润得数码科技有限责任公司 | A kind of antenna isolated location and isolation tune two-in-one die set |
| CN208636845U (en) * | 2018-08-20 | 2019-03-22 | 紫光同芯微电子有限公司 | Novel non-contact transponder receives circuit |
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