CN105005753A - NFC apparatus - Google Patents
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- CN105005753A CN105005753A CN201510486362.0A CN201510486362A CN105005753A CN 105005753 A CN105005753 A CN 105005753A CN 201510486362 A CN201510486362 A CN 201510486362A CN 105005753 A CN105005753 A CN 105005753A
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Abstract
Disclosed in the invention is a near-field communication (NFC) apparatus comprising a receiving link, a modulation link, a coil and a signal processing apparatus. The receiving link receives a request signal sent by external equipment based on coil coupling, carries out demodulation on the request signal and then transmits the demodulated request signal to the signal processing apparatus for processing; and the signal processing apparatus controls the modulation link to send a response signal corresponding to the request signal to the external equipment based on coupling of the coil with the coil of the external equipment. The receiving link contains a Schmidt comparator, a level converting device, and a demodulation device, wherein the units are successively connected in series; and the other terminal of the Schmidt comparator is electrically connected with a first terminal of the coil. The modulation link includes a modulation device, a current converting module and a current amplifying device; the current converting module is used for converting a voltage signal passing through the modulation device into a current signal; the current amplifying device is used for amplifying the current signal; and other terminals of the current amplifying device are electrically connected with the coil. The NFC apparatus uses a few electronic devices and thus the cost is low.
Description
Technical field
The present invention relates to technical field of near field communication, particularly relate to a kind of NFC communication device.
Background technology
In recent years, along with the development of mobile Internet, take smart mobile phone as the mobile device of representative, because it is easy to carry, the features such as application extension is versatile and flexible, become more and more important information interactive terminal.The demand of mobile device to closely interconnection technique makes NFC (Near Field Communication, close range wireless communication) technology have found its application platform applicable.Utilize NFC technique, easily can realize identification fast, mobile payment, the contents such as the exchanges data between two mobile devices.The receiver of common NFC communication device is the circuit being positioned at chip exterior, and the electronic component that receiver is positioned at needed for chip exterior is more, and cost is higher.
Summary of the invention
Based on this, be necessary the NFC communication device providing a kind of number of electronic components less.
A kind of NFC communication device, comprises receiver, modulation link, coil and signal processing apparatus; Described receiver receives by being coupled of described coil and external device coil the request signal that described external device sends, and processes being transferred to described signal processing apparatus after described request signal receiving; Described signal processing apparatus controls the coil coupling of described modulation link by described coil and described external device, and outwardly equipment sends the answer signal corresponding with described request signal;
Described receiver comprises Schmidt's comparer, level converter and the demodulating equipment of connecting successively; The other end of described Schmidt's comparer is electrically connected with the first end of described coil;
Described modulation link comprises modulating device, current conversion module and the current-amplifying device of connecting successively; Described current conversion module is used for the current signal voltage signal through described modulating device being converted to default size; Described current-amplifying device is used for described current signal to amplify; Other ends of described current-amplifying device are electrically connected with described coil.
Wherein in an embodiment, described receiver also comprises amplification module, and described amplification module comprises the first switch and amplifier group;
Described first switch is in parallel with described amplifier group, and the first end of described first switch is electrically connected with the first end of described coil, and the second end of described first switch is electrically connected with described Schmidt's comparer;
Described Schmidt's comparer is electrically connected with the first end of described coil by described first switch or described amplifier group.
Wherein in an embodiment, described amplifier group comprises the amplifier that an amplifier or two or more are in parallel, and each described amplifier has a default enlargement factor scope, and the enlargement factor scope of amplifier described in each is not overlapping
Wherein in an embodiment, described receiver also receives the clock signal of described external device transmission by described coil, and processes being transferred to described signal processing apparatus after described clock signal reception;
At described modulation antenna efficiency and the modulation signal that produces of described modulation link when being high level, the amplitude of described clock signal diminishes, under load-modulate pattern, described signal processing apparatus controls the work of described amplifier group, and the amplitude of the part that the amplitude of described clock signal diminishes by described amplifier group is amplified to the range value of preset range.
Wherein in an embodiment, described receiver also comprises the first coupling capacitance, and the first end of described first coupling capacitance is electrically connected with the first end of described first switch, and the second end of described first coupling capacitance is electrically connected with the first end of described coil;
Described Schmidt's comparer is electrically connected with the first end of described coil by described amplification module and described first coupling capacitance successively.
Wherein in an embodiment, described receiver also comprises current-limiting resistance, and the first end of described current-limiting resistance is electrically connected with the first end of described first coupling capacitance, and the second end of described current-limiting resistance is electrically connected with the first end of described first switch;
Described Schmidt's comparer is electrically connected with the first end of described coil by described amplification module, described current-limiting resistance and described first coupling capacitance successively.
Wherein in an embodiment, described receiver also comprises clamp circuit, and described Schmidt's comparer is electrically connected with the first end of described coil by described clamp circuit and described amplification module successively.
Wherein in an embodiment, described clamp circuit comprises the first resistance and the second resistance that are in series; Another termination power of described first resistance, the other end ground connection of described second resistance; The resistance of described first resistance is equal with the resistance of described second resistance.
Wherein in an embodiment, described current conversion module is transfer resistance; Or
Described current conversion module is adjustable current array, the power supply termination power of described adjustable current array, and the controlled terminal of described adjustable current array connects described modulating device, current-amplifying device described in the output termination of described adjustable current array.
Wherein in an embodiment, described current conversion module comprises second switch, transfer resistance and adjustable current array;
Described transfer resistance one termination current-amplifying device, the output terminal of adjustable current array described in another termination of described transfer resistance and the first end of described second switch, the power supply termination power of described adjustable current array, the controlled terminal of described adjustable current array connects described modulating device, modulating device described in the second termination of described second switch;
When described adjustable current array operation, described transfer resistance is shorted or the value of described transfer resistance is zero; When described adjustable current array does not work, described transfer resistance value is the first resistance value.
Wherein in an embodiment, described current-amplifying device is triode, the base stage of described triode is electrically connected with the output terminal of described current conversion module, the collector of described triode is electrically connected with the first end of described coil, and the emitter of described triode is electrically connected with the second end of described coil.
Wherein in an embodiment, described NFC communication device also comprises the second electric capacity be in parallel with described coil.
Above-mentioned NFC communication device, receiver comprises Schmidt's comparer, level converter and demodulating equipment, modulation link comprises modulating device, current conversion module and current-amplifying device, adopt less electronic component, the solution that can complete the request signal that equipment to external world sends is in harmonious proportion modulates, and provides cost savings.Further, the recovering clock signals that external device also can send by above-mentioned NFC communication device becomes the reference clock signal of modulation link, and this reference clock signal be the recovering clock signals that external device sent through receiver out, therefore additionally reference clock need not be provided, and precision is higher, error is less.
Accompanying drawing explanation
Fig. 1 is the electrical block diagram of a NFC communication device of the present invention embodiment;
Fig. 2 is that the request signal that sends of external device in NFC communication device of the present invention embodiment is through receiver waveform schematic diagram everywhere;
Fig. 3 be the clock signal that sends of external device in NFC communication device of the present invention embodiment under load-modulate through receiver waveform schematic diagram everywhere.
Embodiment
For making object of the present invention, technical scheme and advantage clearly understand, be described below in conjunction with the embodiment of accompanying drawing to NFC communication device of the present invention.Should be appreciated that specific embodiment described herein only in order to explain the present invention, be not intended to limit the present invention.
See Fig. 1, in an embodiment, NFC communication device of the present invention comprises receiver 100, modulation link 200, coil L and signal processing apparatus 300.Receiver 100 receives by being coupled of coil L and external device coil the request signal that external device sends, and flows to signal processing apparatus 300 by after request signal demodulation.Signal processing apparatus 300 controls the coil coupling that modulation link 200 passes through coil L and external device, and outwardly equipment sends the response letter corresponding with request signal.
Concrete, receiver 100 comprises Schmidt's comparer 130, level converter 120 and the demodulating equipment 110 of connecting successively.Schmidt's comparer 130 one end is electrically connected with the input end of level converter 120, and the other end is electrically connected with the first end of coil L.
Modulation link 200 comprises modulating device 210, current conversion module 220 and the current-amplifying device 230 of connecting successively.Current conversion module 220 is for being converted to the modulated current signal of default size by the modulated voltage signal through over-modulating device 210.Current-amplifying device 230 is for amplifying modulated current signal.One end of current-amplifying device 230 is electrically connected with the output terminal of current conversion module 220, and other ends are electrically connected with coil L.
Understandable, when receiving the request signal that external device sends, modulation link 200 is idle, or perhaps modulation dynamics is zero.Now, the working condition of receiver 100 is as follows: the request signal that coil L receives is processed into the digital signal of low and high level by Schmidt's comparer 130; Digital signal processing after Schmidt's comparer 130 processes by level converter 120 becomes to be applicable to the digital signal that demodulating equipment 110 processes; Digital demodulation signal after level converter 120 processes by demodulating equipment 110 goes out the information that external device sends.
After the request signal receiving external device transmission, signal processing apparatus 300 controls modulation link 200 and starts working: modulating device 210 exports modulated voltage signal according to the control of signal processing apparatus 300; Current conversion module 220 converts the modulated voltage signal that modulating device 210 sends to modulated current signal; Current-amplifying device 230 generates modulation intelligence after being amplified by modulated current signal, by the coil coupling of coil L and external device, modulation intelligence is passed to external device.
Above-mentioned NFC communication device, receiver 100 comprises Schmidt's comparer 130, level converter 120 and demodulating equipment 110, modulation link 200 comprises modulating device 210, current conversion module 220 and current-amplifying device 230, adopt less electronic component, the solution that can complete the request signal that equipment to external world sends is in harmonious proportion modulates, and provides cost savings.
In the present embodiment, Schmidt's comparer 130, level converter 120 and demodulating equipment 110 are all positioned at NFC communication device chip, and modulating device 210, current conversion module 220 are also positioned at NFC communication device chip.
Understandable, the signal amplitude that the external device that coil L receives sends is general larger, therefore the signal that external device sends can be passed straight through to Schmidt's comparer 130.And the situation that the signal amplitude that the external device received for coil L sends is less, be then resent to Schmidt's comparer 130 after needing to amplify signal.Therefore, receiver 100 can also comprise amplification module 150.Concrete, amplification module 150 comprises the first switch S 1 and amplifier group 151.Wherein, the first switch S 1 is in parallel with amplifier group 151, and the first end of the first switch S 1 is electrically connected with the first end of coil L, and the second end of the first switch S 1 is electrically connected with Schmidt's comparer 130.Schmidt's comparer 130 is electrically connected with the first end of coil L by the first switch S 1 or amplifier group 150.
In an embodiment, amplifier group 151 comprises two amplifiers parallel with one another, such as the first amplifier O1 and the second amplifier O2.First amplifier O1 and the second amplifier O2 all has a default enlargement factor scope, and the enlargement factor scope of the first amplifier O1 and the second amplifier O2 is not overlapping.Preferably, the first amplifier O1 is the high-gain amplifier that enlargement factor is larger, and the second amplifier O2 is the low gain amplifier that enlargement factor is less.Like this, the first switch S 1, first amplifier O1 and the second amplifier O2 three form one and have straight-through, low gain to signal and amplify or the structure of plus and blowup.Certainly, the first amplifier O1 and the second amplifier O2 can all have several gear to regulate, thus the structure that the first switch S 1, first amplifier O1 and the second amplifier O2 are formed is to the gain amplifier of signal or straight-throughly have larger range of adjustment.Certainly, in other embodiments, amplifier group 151 can also comprise an amplifier or two or more amplifier parallel with one another.
In an embodiment, receiver 100 can also comprise the first coupling capacitance C1.First coupling capacitance C1 connects with amplification module 150.Concrete, the first end of the first coupling capacitance C1 is electrically connected with the first end of the first switch S 1, and second end of the first coupling capacitance C1 is electrically connected with the first end of coil L.Therefore, Schmidt's comparer 130 is electrically connected with the first end of coil L by amplification module 150 and the first coupling capacitance C1 successively.First coupling capacitance C1 is set, the forceful electric power signal by the first coupling capacitance C1 and weak electric signal isolation can be made, and the path of high-frequency signal is provided, stop power current to enter weak electricity system, to ensure the safe handling of equipment.
In an embodiment, consider when the amplitude of the signal that the external device that coil L receives sends is excessive, larger electric current can be produced and flow to receiver 100, likely damage be caused to each ingredient of receiver 100.Therefore, receiver 100 can also comprise current-limiting resistance R1.Current-limiting resistance R1 and the first coupling capacitance C1 and amplification module 150 are in series.The first end of current-limiting resistance R1 is electrically connected with the first end of the first coupling capacitance C1, and second end of current-limiting resistance R1 is electrically connected with the first end of the first switch S 1.Schmidt's comparer 130 is electrically connected with the first end of coil L by amplification module 150, current-limiting resistance R1 and the first coupling capacitance C1 successively.I/O module is well known to those skilled in the art, and be simplified illustration, I/O module is not shown in instances.
Preferably, receiver 100 also comprises clamp circuit 140.Schmidt's comparer 130 is electrically connected with the first end of coil L by clamp circuit 140 and amplification module 150 successively.Concrete, clamp circuit 140 can comprise the first resistance R2 and the second resistance R3 that are in series.Another termination power of first resistance R2, the other end ground connection of the second resistance R3.The resistance of the first resistance R2 is equal with the resistance of the second resistance R3.Clamp circuit 140 is set, by clamp circuit 140, the central value of signal amplitude is arranged to the half numerical value of the supply voltage of clamp circuit 140.Certainly, clamp circuit 140 can also be other circuit structures, due to the technology that clamp circuit is well known to those skilled in the art, therefore does not repeat them here.
In an embodiment, current conversion module 220 can be that the two ends of transfer resistance R4, transfer resistance R4 are electrically connected with modulating device 210 and current-amplifying device 230 respectively.Under this scheme, the modulated voltage signal sent by modulating device 210, after transfer resistance R4, is converted to modulated current signal.Transfer resistance R4 can be the resistance of fixed resistance value, also can be the adjustable resistance of resistance size.The resistance of transfer resistance R4 can be any resistance between tens kilo-ohms to hundreds of kilo-ohm.
In addition, current conversion module 220 can also be adjustable current array 221.The power supply termination power of adjustable current array 221, the controlled terminal of adjustable current array 221 connects modulating device 210, the output termination current-amplifying device 230 of adjustable current array 221.Under this scheme, arranged by adjustable current array 221 to suitable current value, the modulated voltage signal sent by modulating device 210, after adjustable current array 221, is converted to modulated current signal.
In an embodiment, current conversion module 220 can also comprise second switch S2, transfer resistance R4 and adjustable current array 221.The modulated voltage signal that modulation module 210 sends, through transfer resistance R4 or adjustable current array 221, is converted into modulated current signal.Concrete, the circuit structure of current conversion module 220 can be: the output terminal of another termination adjustable current array 221 of transfer resistance R4 mono-termination current-amplifying device 230, transfer resistance R4 and the first end of second switch S2.The power supply termination power of adjustable current array 221, the controlled terminal of adjustable current array 221 connects modulating device 210, the second termination modulating device 210 of second switch S2.When adjustable current array 221 works, second switch S2 opens, and transfer resistance R4 is shorted or the resistance of transfer resistance R4 is zero.When adjustable current array 221 does not work, second switch S2 closes, and the value of transfer resistance R4 is the first resistance value, and the first resistance value can be any resistance between tens kilo-ohms to hundreds of kilo-ohm.In this scheme, transfer resistance R4 can be the adjustable resistance of resistance size.
Understandable, in other embodiments, the circuit structure of current conversion module 220 can also be: transfer resistance R4 connects with second switch S2, transfer resistance R4 after series connection and second switch S2 is that adjustable current array 221 is in parallel, and the transfer resistance R4 after series connection and the two ends of second switch S2 are electrically connected with the controlled terminal of adjustable current array and output terminal respectively.Now, transfer resistance can be the adjustable resistance of the resistance of fixed resistance value or resistance size.The resistance of transfer resistance R4 can be any resistance between tens kilo-ohms to hundreds of kilo-ohm.
In an embodiment, current-amplifying device 230 is triode Q.The output terminal of current conversion module 220 is electrically connected with the base stage of triode Q.The collector of triode Q is electrically connected with the first end of coil L, and the emitter of triode Q is electrically connected with second end of coil L.The voltage amplitude that triode Q is used in modulation coil L after being amplified by modulated current signal.Certainly, in other embodiments, current-amplifying device 230 can also can the device of amplified current for other, and the cost of triode Q is lower.
Understandable, in the process that modulation link 200 works, modulation link 200 needs a reference clock.And when modulating link 200 and working, the coil of external device still sends signal by being coupled to receiver 100 with coil L.Therefore, can by when modulating link 200 and working, the signal recuperation sent by external device by receiver 100 becomes the reference clock of modulation needed for link 200, and does not need the reference clock signal of extra increase modulation needed for link 200.
Concrete, receiver 100 also receives the clock signal of external device transmission by coil L, and sends to signal processing apparatus 300 by after clock signal process.When modulating link 200 and work and modulate modulation signal that link 200 produces being high level, the amplitude of clock signal under the effect of load-modulate after coupling can be dragged down, and signal processing apparatus 300 is understood control amplifier group 151 and worked.The amplitude of the part that the amplitude of clock signal diminishes by amplifier group 151 is amplified to the range value of preset range.Concrete, amplifier group 151 can only be amplified by the part dragged down by the amplitude of the clock signal after dragging down, and also can amplify by the entirety of the clock signal after dragging down.Due to this reference clock signal be the signal recuperation that external device sent through receiver out, therefore additionally need not provide reference clock, and precision is higher, error is less.
In the present embodiment, the resistance of transfer resistance R4 can not be excessive or too small, if the resistance of transfer resistance R4 is excessive, then the depth of modulation of modulating link 200 is too little, and modulation link 200 may not have modulating action; If the resistance of transfer resistance R4 is too small, then the depth of modulation of modulating link 200 is too large, may affect the recovery of reference clock.Concrete, the selectable resistance values of transfer resistance R4 is taken between tens kilo-ohms to hundreds of kilo-ohm.Certainly, the resistance of transfer resistance R4 is also relevant with the enlargement factor of amplifier group 151 to the enlargement factor of triode Q.Therefore, the span of above-mentioned transfer resistance R4 resistance is a recommended value, and concrete value can convert according to practical situations.
In the present embodiment, the part removed in receiver 100 beyond first coupling capacitance C1 and current-limiting resistance R1 can all be positioned at NFC communication device chip, and in modulation link 200, the part removed beyond current-amplifying device 230 and transfer resistance R4 can all be positioned at NFC communication device chip.
In an embodiment, NFC communication device also comprises the second electric capacity C2 be in parallel with coil L.By selecting suitable coil model, namely inductance value size, and the size of the second suitable capacitance, near the frequency of operation (such as 13.56MHz) tuning-points can being adjusted to NFC, thus there is better selecting frequency characteristic, coupling effect between coil L and the coil of external equipment is better, and Signal transmissions is better.
Referring to Fig. 1, Fig. 2 and Fig. 3, the structure of NFC communication device of the present invention and workflow are further described.
See Fig. 1, receiver 100 comprises the first coupling capacitance C1, current-limiting resistance R1, amplification module 150, clamp circuit 140, Schmidt's comparer 130, level converter 120 and the demodulating equipment 110 of connecting successively.Wherein, amplification module 150 comprises the first switch S 1, the first amplifier O1 and the second amplifier O2 that are in parallel.Clamp circuit 140 comprises two the first resistance R2 and the second resistance R3 that are in series.Level converter 120 can be level translator.Demodulating equipment 110 can be detuner.The first end of the first coupling capacitance C1 is electrically connected with current-limiting resistance R1.
Modulation link 200 comprises triode Q, current-amplifying device 220 and the modulating device 210 of connecting successively.Wherein, current-amplifying device 220 comprises transfer resistance R4, second switch S2 and adjustable current array 221.The output terminal of another termination adjustable current array 221 of transfer resistance R4 mono-termination current-amplifying device 230, transfer resistance R4 and the first end of second switch S2.The power supply termination power of adjustable current array 221, the controlled terminal of adjustable current array 221 connects modulating device 210, the second termination modulating device 210 of second switch S2.
The two ends of coil L are parallel with the second electric capacity C2.The first end of coil L is electrically connected with the collector of the other end of the first coupling capacitance C1 and triode Q, and second end of coil L is electrically connected with the emitter of triode Q, and the second end ground connection of coil L.The other end of demodulating equipment 110 is electrically connected with signal processing apparatus 300.The other end of modulating device 210 is electrically connected with signal processing apparatus 300.According to contactless specification, dissimilar interface traffic channel is different, be modulated to example with the ASK of category-A (Amplitude ShiftKeying, amplitude-shift keying) 100% in the present embodiment, function and the advantage of NFC communication device of the present invention are described.In category-A ASK100% modulated process, be carry out communicating between PCD (proximity Coupling device) with PICC (proximity card) by " time-out " state, the envelope monotone decreasing that " time-out " state can be understood as PCD field is interval to the part of be less than its initial value 5%.
See Fig. 2, PICC is placed in the radio-frequency field of PCD read write line, now the coil of PCD read write line is close with coil L, shown in the A1 waveform that the request signal waveform that PCD read write line sends is Fig. 2.The request signal receiving the transmission of PCD read write line is sent to receiver 100 by coil L, and after the first coupling capacitance C1, current-limiting resistance R1 and the first switch S 1, the signal of formation is as shown in B1 waveform.Because the first switch S 1 of amplification module 150 works, and amplifier group 151 does not work, and therefore the amplitude of the relative A1 waveform of the amplitude of B1 waveform does not change.Certainly, if selective amplifier group 151 works and the first switch S 1 does not work, then the amplitude of the relative A1 waveform of the amplitude of B1 waveform can change.B1 waveform signal is through clamp circuit 140, and because clamp circuit 140 comprises two resistances the first equal resistance R2 and the second resistance R3, therefore the numerical value of the central point of B1 wave-shape amplitude is clamp circuit 140 supply voltage V
dDthe half of numerical value.And the signal higher than predetermined threshold value voltage can be placed in high level by Schmidt's comparer 130, signal lower than predetermined threshold value voltage is placed in low level, therefore B1 waveform signal is after clamp circuit 140 and Schmidt's comparer 130, and the signal of formation is as shown in C1 waveform.Because the operating voltage of demodulating equipment 110 is 1.2V, and the high level of C1 waveform signal is 3.3V, therefore needs to adopt level converter 120 that the high level of C1 waveform signal is converted to 1.2V.Demodulating equipment 110 sends to signal processing apparatus 300 after the signal after level converter 120 switching levels is carried out demodulation.
Modulating device 210 exports modulation signal CLKm according to the control of signal processing apparatus 300, and now modulation signal CLKm is modulated voltage signal, can be modulated by following two kinds of modes to modulation signal CLKm.A kind of mode closes adjustable current array 221, second switch S2 to close, and by second switch S2 and transfer resistance R4, modulated voltage signal CLKm is converted to modulated current signal.Now, transfer resistance R4 has certain resistance.Another kind of mode disconnects second switch S2, resistance that transfer resistance R4 is set to zero or by transfer resistance R4 short circuit, and adjustable current array 221 is set to suitable current value, by adjustable current array 221, modulated voltage signal CLKm is converted to modulated current signal.Then by triode Q, modulated current signal is amplified.
After the signal receiving the transmission of PCD read write line, PICC is needed to reply answer signal, and when PICC does not export modulation signal, PCD read write line can continue the clock signal sending 13.56MHz, this clock signal can use as the reference clock of modulation link 200 after receiver 100.See Fig. 3, when modulation signal CLKm is high level, the amplitude of the clock signal of the 13.56MHz that PCD read write line that coil L receives sends can be dragged down, and the clock signal after dragging down as shown in A2, and is inaccurate by the clock signal A2 after dragging down as the reference clock of modulation link 200.In the present embodiment, signal processing apparatus 300 detects that control amplifier group 151 works by after the clock signal A2 after dragging down, by being amplified to the range value of preset range by the part dragged down by the amplitude of the clock signal A2 after dragging down, as shown in B2.Signal B2 is after clamp circuit 140 and Schmidt's comparer 130, and the signal of generation is as shown in C2.And signal C2 meets the requirement of the reference clock signal of modulation link 200, can use as the reference clock signal of modulation link 200.
It should be noted that, signal processing apparatus 300 can control amplifier group 151 with suitable gain work, the range value of preset range will be amplified to by the part dragged down by the amplitude of the clock signal A2 after dragging down.And for by the amplitude of the clock signal A2 after dragging down not by the part dragged down, then no requirement (NR).Namely amplifier group 151 can only be amplified by the part dragged down by the amplitude of the clock signal A2 after dragging down, and also can amplify by the clock signal A2 entirety after dragging down.
Above-mentioned NFC communication device, adopts less electronic component, and the solution of the request signal that the equipment to external world that can complete sends is in harmonious proportion modulates, and provides cost savings.In addition, receiver 100 can also when modulating link 200 and working, the clock signal that external device sends is carried out Recovery processing, the final reference clock signal generating modulation link 200, thus do not need the reference clock signal of extra increase modulation needed for link 200, and due to this reference clock signal be the signal recuperation that external device sent through receiver 100 out, therefore additionally need not provide reference clock, and precision is higher, error is less.
The above embodiment only have expressed several embodiment of the present invention, and it describes comparatively concrete and detailed, but therefore can not be interpreted as the restriction to the scope of the claims of the present invention.It should be pointed out that for the person of ordinary skill of the art, without departing from the inventive concept of the premise, can also make some distortion and improvement, these all belong to protection scope of the present invention.Therefore, the protection domain of patent of the present invention should be as the criterion with claims.
Claims (12)
1. a NFC communication device, is characterized in that, comprises receiver, modulation link, coil and signal processing apparatus; Described receiver receives by being coupled of described coil and external device coil the request signal that described external device sends, and processes being transferred to described signal processing apparatus after described request signal receiving; Described signal processing apparatus controls the coil coupling of described modulation link by described coil and described external device, sends the answer signal corresponding with described request signal to described external device;
Described receiver comprises Schmidt's comparer, level converter and the demodulating equipment of connecting successively; The other end of described Schmidt's comparer is electrically connected with the first end of described coil;
Described modulation link comprises modulating device, current conversion module and the current-amplifying device of connecting successively; Described current conversion module is used for the modulated current signal modulated voltage signal through described modulating device being converted to default size; Described current-amplifying device is used for described current signal to amplify; Other ends of described current-amplifying device are electrically connected with described coil.
2. NFC communication device according to claim 1, is characterized in that, described receiver also comprises amplification module, and described amplification module comprises the first switch and amplifier group;
Described first switch is in parallel with described amplifier group, and the first end of described first switch is electrically connected with the first end of described coil, and the second end of described first switch is electrically connected with described Schmidt's comparer;
Described Schmidt's comparer is electrically connected with the first end of described coil by described first switch or described amplifier group.
3. NFC communication device according to claim 2, it is characterized in that, described amplifier group comprises the amplifier that an amplifier or two or more are in parallel, and each described amplifier has a default enlargement factor scope, and the enlargement factor scope of amplifier described in each is not overlapping.
4. NFC communication device according to claim 2, is characterized in that, described receiver also receives the clock signal of described external device transmission by described coil, and is transferred to described signal processing apparatus by after described clock signal process;
At described modulation antenna efficiency and the modulation signal that produces of described modulation link when being high level, the amplitude of described clock signal diminishes, under load-modulate pattern, described signal processing apparatus controls the work of described amplifier group, and the amplitude of the part that the amplitude of described clock signal diminishes by described amplifier group is amplified to the range value of preset range.
5. NFC communication device according to claim 2, it is characterized in that, described receiver also comprises the first coupling capacitance, and the first end of described first coupling capacitance is electrically connected with the first end of described first switch, and the second end of described first coupling capacitance is electrically connected with the first end of described coil;
Described Schmidt's comparer is electrically connected with the first end of described coil by described amplification module and described first coupling capacitance successively.
6. NFC communication device according to claim 5, it is characterized in that, described receiver also comprises current-limiting resistance, and the first end of described current-limiting resistance is electrically connected with the first end of described first coupling capacitance, and the second end of described current-limiting resistance is electrically connected with the first end of described first switch;
Described Schmidt's comparer is electrically connected with the first end of described coil by described amplification module, described current-limiting resistance and described first coupling capacitance successively.
7. NFC communication device according to claim 2, is characterized in that, described receiver also comprises clamp circuit, and described Schmidt's comparer is electrically connected with the first end of described coil by described clamp circuit and described amplification module successively.
8. NFC communication device according to claim 7, is characterized in that, described clamp circuit comprises the first resistance and the second resistance that are in series; Another termination power of described first resistance, the other end ground connection of described second resistance; The resistance of described first resistance is equal with the resistance of described second resistance.
9. NFC communication device according to claim 1, is characterized in that, described current conversion module is transfer resistance; Or
Described current conversion module is adjustable current array, the power supply termination power of described adjustable current array, and the controlled terminal of described adjustable current array connects described modulating device, current-amplifying device described in the output termination of described adjustable current array.
10. NFC communication device according to claim 1, is characterized in that, described current conversion module comprises second switch, transfer resistance and adjustable current array;
Current-amplifying device described in described transfer resistance one termination, the output terminal of adjustable current array described in another termination of described transfer resistance and the first end of described second switch, the power supply termination power of described adjustable current array, the controlled terminal of described adjustable current array connects described modulating device, modulating device described in the second termination of described second switch;
When described adjustable current array operation, described transfer resistance is shorted or the value of described transfer resistance is zero; When described adjustable current array does not work, described transfer resistance value is the first resistance value.
11. NFC communication devices according to claim 1, it is characterized in that, described current-amplifying device is triode, the base stage of described triode is electrically connected with the output terminal of described current conversion module, the collector of described triode is electrically connected with the first end of described coil, and the emitter of described triode is electrically connected with the second end of described coil.
12. NFC communication devices according to claim 1 to 11 any one, it is characterized in that, described NFC communication device also comprises the second electric capacity be in parallel with described coil.
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| CN201510486362.0A CN105005753B (en) | 2015-08-03 | 2015-08-03 | NFC communication device |
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| CN201510486362.0A CN105005753B (en) | 2015-08-03 | 2015-08-03 | NFC communication device |
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| US20100291869A1 (en) * | 2007-11-15 | 2010-11-18 | Robin Wilson | Near field rf communicators |
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