CN112448709B - SWP main interface circuit and terminal - Google Patents
SWP main interface circuit and terminal Download PDFInfo
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- CN112448709B CN112448709B CN202110133121.3A CN202110133121A CN112448709B CN 112448709 B CN112448709 B CN 112448709B CN 202110133121 A CN202110133121 A CN 202110133121A CN 112448709 B CN112448709 B CN 112448709B
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K19/00—Logic circuits, i.e. having at least two inputs acting on one output; Inverting circuits
- H03K19/0008—Arrangements for reducing power consumption
- H03K19/0013—Arrangements for reducing power consumption in field effect transistor circuits
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K19/00—Logic circuits, i.e. having at least two inputs acting on one output; Inverting circuits
- H03K19/003—Modifications for increasing the reliability for protection
- H03K19/00315—Modifications for increasing the reliability for protection in field-effect transistor circuits
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K19/00—Logic circuits, i.e. having at least two inputs acting on one output; Inverting circuits
- H03K19/003—Modifications for increasing the reliability for protection
- H03K19/00346—Modifications for eliminating interference or parasitic voltages or currents
- H03K19/00361—Modifications for eliminating interference or parasitic voltages or currents in field effect transistor circuits
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K19/00—Logic circuits, i.e. having at least two inputs acting on one output; Inverting circuits
- H03K19/0175—Coupling arrangements; Interface arrangements
- H03K19/017509—Interface arrangements
Abstract
The invention provides an SWP main interface circuit and a terminal, wherein the circuit comprises: an SWP host interface; the voltage pulse transmitting unit is used for generating two paths of first digital modulation signals and second digital modulation signals with different edges according to the initial digital modulation signal and respectively controlling the SWP main interface to transmit the voltage pulse modulation signals to the SWP slave interface based on the first digital modulation signals and the second digital modulation signals; and the current receiving unit is respectively connected with the SWP main interface and the voltage pulse transmitting unit and is used for receiving the current modulation signal sent by the SWP slave interface from the SWP main interface based on a current threshold when the SWP main interface sends the voltage pulse modulation signal. The circuit can generate two paths of first digital modulation signals and second digital modulation signals with different edges, and controls the transmission of the voltage pulse modulation signals through the two paths of signals, thereby being beneficial to reducing a large number of interference signals and reducing the power consumption when the circuit transmits.
Description
Technical Field
The invention relates to the technical field of near field communication, in particular to an SWP (single wire protocol) main interface circuit and a terminal.
Background
Near Field payment is a mobile payment technology based on Near Field Communication (NFC) technology, and can be conveniently applied to embedded smart devices such as mobile phones, hand rings, computers, and the like, and at present, a main Near Field payment scheme is an SWP-SIM Card scheme, in which an SWP (single wire protocol) interface on NFC is used as a master interface of SWP-SIM Communication, and an SWP interface on UICC (Universal Integrated Circuit Card) is used as a slave interface of SWP-SIM Communication. Therefore, the design and research of the high-performance and low-cost SWP main interface circuit have very important significance. The SWP main interface is a key interface for realizing single-wire full-duplex communication between the UICC card and the NFC front-end chip, and the performance of the SWP main interface is directly related to the communication quality of the NFC front-end chip card and the UICC card.
In the related art, the SWP master interface circuit is shown in fig. 1, wherein a digital modulation signal SWPIN passes through a transmitting unit composed of a buffer BUF1, a transistor PM1, a transistor NM1 and a resistor R1, and a transmitting voltage signal S1 is transmitted to the SWP slave interface, thereby completing a transmitting function. However, when the SWPIN level is inverted, PM1 and NM1 have a period of time to turn on simultaneously, which causes two problems: the demodulated output signal contains a plurality of interfering signals; and secondly, the power consumption of the circuit is increased.
Disclosure of Invention
The present invention is directed to solving, at least to some extent, one of the technical problems in the related art.
The main technical scheme of the invention is as follows.
An embodiment of a first aspect of the present invention provides an SWP host interface circuit, including: an SWP host interface; the voltage pulse transmitting unit is connected with the SWP main interface and used for generating two paths of first digital modulation signals and second digital modulation signals with different edges according to an initial digital modulation signal and respectively controlling the SWP main interface to send voltage pulse modulation signals to the SWP slave interface based on the first digital modulation signals and the second digital modulation signals; and the current receiving unit is respectively connected with the SWP main interface and the voltage pulse transmitting unit and is used for receiving the current modulation signal sent by the SWP slave interface from the SWP main interface based on a current threshold value under the condition that the voltage pulse modulation signal is at a high level.
According to an embodiment of the invention, the SWP master interface circuit further comprises: the receiving threshold adjusting unit is connected with the current receiving unit and is used for adjusting the current threshold.
According to an embodiment of the invention, the SWP master interface circuit further comprises: an electrostatic protection unit, comprising: the SWP circuit comprises a first diode, a second diode and a first resistor, wherein one end of the first resistor is connected with the SWP main interface, the other end of the first resistor is respectively connected with the anode of the first diode, the cathode of the second diode, the voltage pulse transmitting unit and the current receiving unit, the cathode of the first diode is connected with a power supply end, and the anode of the second diode is connected with a ground end.
According to an embodiment of the present invention, the voltage pulse transmitting unit includes: the digital modulator comprises a first buffer, a signal processor, a first PMOS transistor, a first NMOS transistor and a second resistor, wherein the input end of the first buffer is used for receiving an initial digital modulation signal, the output end of the first buffer is connected with the input end of the signal processor, the first output end of the signal processor is connected with the grid electrode of the first PMOS transistor, the second output end of the signal processor is connected with the grid electrode of the first NMOS transistor, the drain electrode of the first PMOS transistor is connected with one end of the second resistor, the other end of the second resistor is respectively connected with the drain electrode of the first NMOS transistor, the anode of the first diode and the current receiving unit, the source electrode of the first PMOS transistor is connected with a power supply end, and the source electrode of the first NMOS transistor is connected with the ground end; the signal processor is used for controlling the first output end to output a first digital modulation signal according to the output signal of the first buffer, and controlling the first PMOS transistor to be switched on and off through the first digital modulation signal; and the second output end is controlled to output a second digital modulation signal according to the output signal of the first buffer, and the first NMOS transistor is controlled to be switched on and switched off through the second digital modulation signal.
According to an embodiment of the present invention, the current receiving unit includes: the receiving circuit comprises a second PMOS transistor, a third resistor, a delayer, a comparator, a D trigger and a second buffer, wherein the grid electrode of the second PMOS transistor is connected with the ground end, the source electrode of the second PMOS transistor is connected with the source electrode of the first PMOS transistor, the drain electrode of the second PMOS transistor is connected with one end of the third resistor, the positive input end of the comparator is respectively connected with the other end of the third resistor and the receiving threshold adjusting unit, the negative input end of the comparator is connected with the positive electrode of the first diode, the output end of the comparator is connected with the D input end of the D trigger, the input end of the delayer is connected with the first output end of the signal processor, the output end of the delayer is connected with the CK input end of the D trigger, and the output end of the D trigger is connected with the input end of the second buffer.
According to an embodiment of the present invention, the reception threshold adjusting unit includes: a second NMOS transistor, a third NMOS transistor, a fourth NMOS transistor, a fifth NMOS transistor, a sixth NMOS transistor, a seventh NMOS transistor, an eighth NMOS transistor, a ninth NMOS transistor, and a tenth NMOS transistor, wherein a gate of the second NMOS transistor, a gate of the third NMOS transistor, a gate of the fourth NMOS transistor, a gate of the fifth NMOS transistor, a gate of the sixth NMOS transistor, and a drain of the second NMOS transistor are respectively connected to a reference current input terminal, a gate of the seventh NMOS transistor, a gate of the eighth NMOS transistor, a gate of the ninth NMOS transistor, and a gate of the tenth NMOS transistor are respectively connected to a current threshold adjustment terminal, a source of the second NMOS transistor, a source of the third NMOS transistor, a source of the fourth NMOS transistor, a source of the fifth NMOS transistor, a drain of the fifth NMOS transistor, The source electrode of the sixth NMOS transistor is connected to ground, the drain electrode of the third NMOS transistor is connected to the source electrode of the seventh NMOS transistor, the drain electrode of the fourth NMOS transistor is connected to the source electrode of the eighth NMOS transistor, the drain electrode of the fifth NMOS transistor is connected to the source electrode of the ninth NMOS transistor, the drain electrode of the sixth NMOS transistor is connected to the source electrode of the tenth NMOS transistor, and the drain electrode of the seventh NMOS transistor, the drain electrode of the eighth NMOS transistor, the drain electrode of the ninth NMOS transistor, and the drain electrode of the tenth NMOS transistor are connected to the positive input end of the comparator; the receiving threshold adjusting unit is specifically configured to adjust the current threshold through the adjusting terminal of the current threshold.
According to an embodiment of the present invention, the SWP master interface circuit further includes: and the digital demodulation unit is connected with the output end of the current receiving unit and is used for demodulating the output signal output by the current receiving unit so as to analyze the data sent by the SWP from the interface.
According to one embodiment of the invention, the adjustment range of the current threshold is 50 uA-750 uA, and the adjustment precision of the current threshold is 50 uA/bit.
According to one embodiment of the invention, the magnitude of the current threshold is 400uA ± 50 uA.
In a second embodiment of the present invention, a terminal is provided, which includes the SWP main interface circuit provided in the first embodiment of the present invention.
According to the technical scheme, the two paths of first digital modulation signals and second digital modulation signals with different edges can be generated, and the two paths of signals are used for controlling the emission of the voltage pulse modulation signals, so that the method and the device are beneficial to reducing a large number of interference signals and reducing the power consumption of a circuit during emission.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The foregoing and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a schematic diagram of a SWP main interface circuit in the related art;
FIG. 2 is a schematic block diagram of an SWP host interface circuit according to an embodiment of the present invention;
FIG. 3A is a timing diagram of a first digital modulation signal and a second digital modulation signal according to an embodiment of the invention;
FIG. 3B is a timing diagram of a first digital modulation signal and a second digital modulation signal according to another embodiment of the present invention;
FIG. 4 is a schematic block diagram of an SWP host interface circuit according to one embodiment of the present invention;
FIG. 5 is a schematic diagram of an SWP host interface circuit according to an example of the present invention;
fig. 6 is a schematic structural diagram of a terminal according to an embodiment of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
It should be noted that, referring to fig. 1, the working principle of the SWP main interface circuit in the related art is as follows: the SWP master interface transmits a voltage signal S1 to the SWP slave interface, and a logic '1' is at a high level in a 3/4 period and a logic '0' is at a low level in a 1/4 period by adopting a level width modulation mode. The SWP slave interface transmits a current signal S2 to the SWP master interface, a load modulation mode is adopted, when an S1 signal is in a high level, a logic '1' modulates a load of 600 uA-1 mA through S1, when an S1 signal is in a low level, a logic '0' modulates a load of-20 uA-0 uA through S1, and the S1 signal and the S2 signal are superposed on a single line to realize full-duplex communication. However, when the SWPIN level is inverted, PM1 and NM1 have a period of time to turn on simultaneously, which causes two problems: the demodulated output signal contains a plurality of interfering signals; and secondly, the power consumption of the circuit is increased.
In order to avoid or reduce the time for PM1 and NM1 to be turned on simultaneously, the embodiment of the invention provides an SWP main interface circuit.
An SWP host interface circuit and terminal according to an embodiment of the present invention will be described with reference to fig. 2-6.
Fig. 2 is a block diagram of an SWP host interface circuit according to an embodiment of the present invention.
As shown in fig. 2, the SWP host interface circuit 100 includes: an SWP main interface 101, a voltage pulse transmitting unit 102, and a current receiving unit 103.
The voltage pulse transmitting unit 102 is connected to the SWP master interface 101, and is configured to generate two paths of first digital modulation signals and second digital modulation signals with different edges according to the initial digital modulation signal, and respectively control the SWP master interface to transmit a voltage pulse modulation signal to the SWP slave interface based on the first digital modulation signal and the second digital modulation signal; the current receiving unit 103 is respectively connected to the SWP master interface 101 and the voltage pulse transmitting unit 102, and is configured to receive the current modulation signal sent by the SWP slave interface from the SWP master interface 101 based on a current threshold when the SWP master interface sends the voltage pulse modulation signal.
It should be noted that, the two signals have different edges, and it can be understood that there is no coincidence between the rising edges of the two signals, and there is no coincidence between the falling edges of the two signals, that is, as shown in fig. 3A and 3B, in the case where both the first digital modulation signal and the second digital modulation signal are at a low level, when the rising edge of the first digital modulation signal arrives, the second digital modulation signal may still be at a low level, when the rising edge of the second digital signal arrives, the first digital modulation signal may still be at a high level, and when the falling edge of the second digital modulation signal arrives, the first digital modulation signal may still be at a high level.
Referring to fig. 3A, when the delay time between the rising edge of the first digital modulation signal and the rising edge of the second digital modulation signal is t, in order to ensure reliable operation of the SWP main interface circuit, the delay time t may be set to a small time value, for example, the delay time t may be 20ns (nanoseconds).
It should be noted that the SWP master interface in the embodiment of the present invention may be understood as an input/output interface of the SWP master interface Circuit, which may be connected to an SWP slave interface of a UICC (Universal Integrated Circuit Card).
Specifically, the initial digital modulation signal SWPIN signal (which may be a high-level signal or a low-level signal) is converted into two paths of first digital modulation signals and second digital modulation signals with different edges after passing through the voltage pulse transmitting unit 102, where rising edges of the first digital modulation signal and the second digital modulation signal do not coincide, and falling edges of the two signals do not coincide, and then the voltage pulse transmitting unit 102 respectively controls the SWP master interface 101 to transmit the voltage pulse modulation signal S1 to the SWP slave interface of the UICC based on the first digital modulation signal and the second digital modulation signal, so as to complete transmission of the voltage pulse modulation signal. While the SWP master interface transmits the voltage pulse modulation signal S1, the SWP master interface 101 may receive the current modulation signal S2 transmitted by the SWP slave interface, and at this time, the current receiving unit 103 of the SWP master interface circuit receives the current modulation signal S2 transmitted by the SWP slave interface from the SWP master interface 101 based on the current threshold to complete the reception of the current modulation signal.
That is, according to the TS 102613 protocol specification defined by ETSI (European Telecommunications Standards Institute), while the SWP master interface 101 transmits the voltage pulse modulation signal S1, the SWP slave interface may transmit the current modulation signal S2, implementing single-wire full duplex communication.
Compared with the SWP main interface circuit in the related art (only one path of signal can be generated), the SWP main interface circuit can generate two paths of first digital modulation signals and second digital modulation signals with different edges, and controls the emission of the voltage pulse modulation signals through the two paths of signals, so that a large number of interference signals are reduced, and the power consumption of the circuit is reduced.
The SWP main interface circuit of the embodiment of the invention can generate two paths of first digital modulation signals and second digital modulation signals with different edges, and controls the emission of the voltage pulse modulation signals through the two paths of signals, thereby being beneficial to reducing a large number of interference signals and reducing the power consumption when the circuit emits.
It should be noted that, in the related art, the current threshold of the received current modulation signal S2 is relatively susceptible to the process, i.e., the current threshold may vary with the process. Therefore, in the embodiment of the invention, the current threshold can be adjusted to make up for the problem of reduced acceptance performance caused by the change of the current threshold along with the change of the process.
That is, in one embodiment of the present invention, as shown in fig. 4, the SWP master interface circuit 100 may further include: receive threshold adjustment unit 104.
The receiving threshold adjusting unit 104 is connected to the current receiving unit 103, and the receiving threshold adjusting unit 104 is configured to adjust the current threshold.
Specifically, the receiving threshold adjusting unit 104 may adjust the current threshold and may transmit the adjusted current threshold to the current receiving unit 103, and the current receiving unit 103 may further receive the current modulation signal S2 transmitted by the SWP slave interface from the SWP master interface 101 based on the adjusted current threshold, so as to complete receiving of the current modulation signal S2.
Therefore, the current threshold is adjusted through the receiving threshold adjusting unit, so that the change of the current threshold along with the process can be compensated, and the receiving performance is improved.
In one embodiment of the present invention, as shown in fig. 5, the SWP master interface circuit 100 may further include: and an electrostatic protection unit 105.
Referring to fig. 4, the electrostatic protection unit may include: a first diode D1, a second diode D2, and a first resistor R1.
One end of the first resistor R1 is connected to the SWP main interface 101 (SWP-PAD end in fig. 4), the other end of the first resistor R1 is connected to the anode of the first diode D1, the cathode of the second diode D2, the voltage pulse emitting unit 102 and the current receiving unit 103, the cathode of the first diode D1 is connected to the power source terminal VDD, and the anode of the second diode D2 is connected to the ground terminal VSS.
Further, referring to fig. 5, the voltage pulse transmitting unit 102 may include: a first buffer BUF1, a signal processor CKP, a first PMOS transistor PM1, a first NMOS transistor NM1, and a second resistor R2.
An input end of the first buffer BUF1 is configured to receive an initial digital modulation signal SWPIN, an output end of the first buffer BUF1 is connected to an input end of the signal processor CKP, a first output end of the signal processor CKP is connected to a gate of the first PMOS transistor PM1, a second output end of the signal processor CKP is connected to a gate of the first NMOS transistor NM1, a drain of the first PMOS transistor PM1 is connected to one end of the second resistor R2, another end of the second resistor R2 is respectively connected to a drain of the first NMOS transistor NM1, an anode of the first diode D1, and the current receiving unit 103, a source of the first PMOS transistor PM1 is connected to a power supply terminal VDD, and a source of the first NMOS transistor NM1 is connected to a ground terminal VSS. It is understood that, referring to fig. 5, the power source terminal of the first buffer BUF1 and the power source terminal of the signal processor CKP are respectively connected to the power source terminal VDD, and the ground terminal of the first buffer BUF1 and the ground terminal of the signal processor CKP are respectively connected to the ground terminal VSS.
The signal processor CKP is configured to control the first output terminal to output the first digital modulation signal OUTN according to an output signal of the first buffer BUF1, and control the first PMOS transistor PM1 to turn on and off through the first digital modulation signal OUTN; the signal processor CKP is further configured to control the second output terminal to output the second digital modulation signal OUTP according to the output signal of the first buffer BUF1, and control the first NMOS transistor NM1 to turn on and off through the second digital modulation signal OUTP.
Specifically, the initial digital modulation signal SWPIN signal passes through the first buffer BUF1 and then is input to the signal processor CKP, and the signal processor CKP generates two paths of first digital modulation signals OUTN and second digital modulation signals OUTP with different edges according to the output signal of the first buffer BUF1, so that the first digital modulation signals OUTN control the on and off of the first PMOS transistor PM1, and the second digital modulation signals OUTP control the on and off of the first NMOS transistor NM 1.
It should be noted that, because the first digital modulation signal OUTN and the second digital modulation signal OUTP are two signals with different edges, and neither the rising edge nor the falling edge of the first digital modulation signal nor the second digital modulation signal coincides (i.e., the rising edge and the falling edge of the two signals do not coincide, nor coincide), when the first PMOS transistor PM1 and the first NMOS transistor NM1 are respectively controlled by the signals OUTN and OUTP, the phenomenon that the two transistors are simultaneously turned on can be avoided, and further, the comparator misjudgment phenomenon caused by a large current flowing through the second resistor R2 when the two transistors are simultaneously turned on can be avoided, and the power consumption when the SWP main interface emits can be reduced.
Specifically, in a certain scenario: the first digital modulation signal OUTN and the second digital modulation signal OUTP are both low level, and at this time, the first PMOS transistor PM1 is in on state and the first NMOS transistor NM1 is in off state. After a period of time, the rising edge of the first digital modulation signal OUTN arrives, so that the first digital modulation signal OUTN controls the first PMOS transistor PM1 to turn off, at this time, the second digital modulation signal OUTP is still a low level signal, that is, the first NMOS transistor NM1 controlled by the second digital modulation signal OUTP is still in an off state, after a delay for a period of time, the second digital modulation signal OUTP becomes a high level signal, at this time, the second digital modulation signal OUTP controls the first NMOS transistor NM1 to turn on, at this time, the SWP main interface 101 outputs a low level. When the falling edge of the second digital modulation signal OUTP arrives, the second digital modulation signal OUTP controls the first NMOS transistor NM1 to turn off, at this time, the first digital modulation signal OUTN is still a high level signal, that is, the second PMOS transistor PM1 controlled by the first digital modulation signal OUTN is still in an off state, the first digital modulation signal OUTN changes to a low level signal after a delay, at this time, the first digital modulation signal OUTN controls the second PMOS transistor PM1 to turn on, at this time, the SWP master interface 101 outputs a high level. That is, since the first digital modulation signal OUTN is a high-level signal for a longer time than the second digital modulation signal OUTP, and the rising edge of the first digital modulation signal OUTN does not overlap the rising edge of the second digital modulation signal OUTP, and the falling edge of the first digital modulation signal OUTN does not overlap the falling edge of the second digital modulation signal OUTP, the second digital modulation signal OUTP is not a high-level signal when the first digital modulation signal OUTN is a low-level signal, and the first PMOS transistor PM1 and the first NMOS transistor NM1 are not simultaneously turned on.
Therefore, the signal processor is introduced into the SWP main interface circuit, the phenomenon that two transistors are conducted simultaneously can be avoided, a large number of interference signals can be reduced, the phenomenon of comparator misjudgment caused by the fact that large current flows through the second resistor when the two transistors are conducted simultaneously can be avoided, and meanwhile power consumption of the SWP main interface during emission can be reduced.
In an embodiment of the present invention, referring to fig. 5, the current receiving unit 103 may include: a second PMOS transistor PM2, a third resistor R3, a DELAY1, a comparator COM1, a D flip-flop DFF1, and a second buffer BUF 2.
Referring to fig. 4, the gate of the second PMOS transistor PM2 is connected to the ground terminal VSS, the source of the second PMOS transistor PM2 is connected to the source of the first PMOS transistor PM1, the drain of the second PMOS transistor PM2 is connected to one end of the third resistor R3, the positive input terminal of the comparator COM1 is connected to the other end of the third resistor R3 and the receiving threshold adjusting unit 104, the negative input terminal of the comparator COM1 is connected to the positive electrode of the first diode D1, the output terminal of the comparator COM1 is connected to the D input terminal of the D flip-flop DFF1, the input terminal of the DELAY1 is connected to the first output terminal of the signal processor CKP, the output terminal of the DELAY1 is connected to the CK input terminal of the D flip-flop DFF1, and the output terminal of the D flip-flop DFF1 is connected to the input terminal of the second buffer BUF 2. It is to be understood that, referring to fig. 4, the power supply terminal of the second buffer BUF2, the power supply terminal of the D flip-flop DFF1, the power supply terminal of the DELAY1, and the power supply terminal of the comparator COM1 are all connected to the power supply terminal VDD, and the ground terminal of the second buffer BUF2, the ground terminal of the D flip-flop DFF1, the ground terminal of the DELAY1, and the ground terminal of the comparator COM1 are all connected to the ground terminal VSS.
Specifically, while the SWP master interface 101 is transmitting the voltage pulse modulated signal S1, the SWP master interface 101 may receive the current modulated signal S2 transmitted by the SWP slave interface. The receiving threshold adjusting unit 104 can adjust the current threshold, the comparator COM1 outputs a high level signal or a low level signal according to the magnitude relation between the adjusted current threshold and the current modulation signal S2, the first digital modulation signal OUTN output by the signal processor CKP samples the output signal of the comparator COM1 through the DELAY1, some interference signals in the output signal of the comparator COM1 are filtered out, the sampled signal is sent to the second buffer BUF2, and the second buffer BUF2 outputs the signal SWPOUT.
Specifically, the current magnitude range of the current modulation signal S2 may be 600uA to 1000uA (microampere), and when the current modulation signal S2 is greater than the current threshold, the output signal of the comparator COM1 is a high level signal; when the current modulation signal S2 is less than or equal to the current threshold, the output signal of the comparator COM1 is a low level signal. The output signal of the comparator COM1 is acquired through the falling edge of the initial digital modulation signal SWPIN, and the output error turning signal of the comparator COM1 caused by the rising edge of the initial digital modulation signal SWPIN is filtered out, so that a large amount of interference signals in the output signal are reduced.
Thus, this embodiment introduces a delay circuit and a D flip-flop in the SWP main interface circuit, which can reduce a large amount of interference signals in the output signal.
It should be noted that, in order to implement the adjustment of the current threshold by the receiving threshold adjusting unit 104, the embodiment of the present invention proposes a structure of the threshold adjusting unit 104, and the following description continues with reference to fig. 5.
In an example of the present invention, referring to fig. 5, the reception threshold adjusting unit 104 may include: a second NMOS transistor NM2, a third NMOS transistor NM3, a fourth NMOS transistor NM4, a fifth NMOS transistor NM5, a sixth NMOS transistor NM6, a seventh NMOS transistor NM7, an eighth NMOS transistor NM8, a ninth NMOS transistor NM9, and a tenth NMOS transistor NM 10.
Wherein a gate of the second NMOS transistor NM2, a gate of the third NMOS transistor NM3, a gate of the fourth NMOS transistor NM4, a gate of the fifth NMOS transistor NM5, a gate of the sixth NMOS transistor NM6, and a drain of the second NMOS transistor NM2 are connected to a reference current input terminal IREF0P5U, respectively, a gate of the seventh NMOS transistor NM7, a gate of the eighth NMOS transistor NM8, a gate of the ninth NMOS transistor NM9, and a gate of the tenth NMOS transistor NM10 are connected to a current threshold adjustment terminal VTH _ TRIM <3:0>, respectively, a source of the second NMOS transistor NM2, a source of the third NMOS transistor NM3, a source of the fourth NMOS transistor NM4, a source of the fifth NMOS transistor NM5, and a source of the sixth NMOS transistor NM6 are connected to a ground terminal VSS, a drain of the third NMOS transistor NM3 is connected to a source of the seventh NMOS transistor NM7, a drain of the fourth NMOS transistor NM4 is connected to a source of the eighth NMOS transistor 8, a drain of the fifth NMOS transistor NM5 is connected to a source of the ninth NMOS transistor NM9, a drain of the sixth NMOS transistor NM6 is connected to a source of the tenth NMOS transistor NM10, and a drain of the seventh NMOS transistor NM7, a drain of the eighth NMOS transistor NM8, a drain of the ninth NMOS transistor NM9, and a drain of the tenth NMOS transistor NM10 are respectively connected to a positive input terminal of the comparator COM 1.
The receiving threshold adjusting unit 104 is specifically configured to adjust the current threshold through the adjusting terminal VTH _ TRIM <3:0> of the current threshold.
Further, the adjustment range of the current threshold can be 50 uA-750 uA (microampere), and the adjustment precision can be 50 uA/bit.
Still further, the magnitude of the current threshold may be 400uA ± 50uA, e.g., the current threshold may be adjusted to 450uA or 350 uA.
Specifically, the current threshold value can be adjusted by adjusting the width-to-length ratio between the second resistor R2 and the third resistor R3, the width-to-length ratio between the first PMOS transistor PM1 and the second PMOS transistor PM1, and the current value of the adjustment terminal VTH _ TRIM <3:0> of the current threshold value.
As will be explained below by a specific example, in a specific example, while the SWP master interface 101 transmits the voltage pulse modulation signal S1, the SWP master interface 101 may simultaneously receive the current modulation signal S2 (600 uA-1000 uA) transmitted by the SWP slave interface, the width-length ratio between the second resistor R2 and the third resistor R3 may be set to 1: 100, the width-length ratio between the first PMOS transistor PM1 and the second PMOS transistor PM1 is 100: 1, and the current value of the adjustment terminal VTH _ TRIM <3:0> of the current threshold is set to 1000uA, then the current threshold of the SWP master interface receiving circuit is 400uA, that is, when the current modulation signal S2 is greater than 400uA, the output signal of the comparator COM1 is at a high level, otherwise, the output signal of the comparator COM1 is sampled after passing through the DELAY circuit DELAY1, and some of the COM signal output by the signal processing circuit CKP is filtered out 1, the sampling signal is sent to the second buffer BUF2, and then the output signal SWPOUT of the second buffer BUF2 is demodulated to obtain correct communication data sent by the SWP slave interface, so as to complete the receiving function of the current modulation signal S2.
It should be noted that the adjustment range and the adjustment precision of the current threshold in the embodiment of the present invention may be determined according to actual requirements, and the size, the range and the adjustment precision of the current threshold are merely exemplary and do not limit the present invention.
Therefore, a receiving threshold value adjusting circuit is introduced into the SWP main interface circuit, so that the current threshold value can be adjusted through the VTH _ TRIM <3:0> port, the current threshold value is compensated to change along with the change of the process, and the receiving performance is improved.
It should be noted that the output signal SWPOUT of the second buffer BUF2 can be digitally demodulated to obtain the correct data transmitted from the interface by the SWP. Based on this, the present invention proposes the following embodiments.
That is, in one embodiment of the present application, the SWP master interface circuit 100 may further include: and the digital demodulation unit is connected with the output end of the current receiving unit 103 and is used for demodulating the output signal output by the current receiving unit 103 so as to analyze the data sent by the SWP from the interface.
Wherein, the output terminal of the current receiving unit 103 can be the output terminal of its second buffer BUF2, that is to say, the output terminal of the second buffer BUF2 can be connected with the digital demodulation unit.
Specifically, the second buffer BUF2 transmits its output signal SWPOUT to the digital demodulation unit, and the numerical demodulation unit performs digital demodulation on the output signal to analyze correct data sent by the SWP from the interface, complete the receiving function of the current modulation signal S2, and implement data reception, thereby improving the receiving accuracy.
In summary, the SWP main interface circuit in the embodiment of the present invention can reduce power consumption during transmission, compensate for the change of the current threshold with the process change by adjusting the current threshold, and reduce interference signals, and has the advantages of simple structure and easy integration.
The embodiment of the invention also provides the terminal. Fig. 6 is a schematic structural diagram of a terminal according to an embodiment of the present invention.
As shown in fig. 6, the terminal 1000 includes the SWP main interface circuit 100 proposed in the above embodiment.
It should be noted that the terminal 1000 may be an intelligent device such as a mobile phone, a bracelet, and a computer.
The terminal of the embodiment of the invention can generate two paths of first digital modulation signals and second digital modulation signals with different edges through the SWP main interface circuit, and controls the transmission of the voltage pulse modulation signals through the two paths of signals, thereby being beneficial to reducing a large number of interference signals and reducing the power consumption when the circuit transmits.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing steps of a custom logic function or process, and alternate implementations are included within the scope of the preferred embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present invention.
The logic and/or steps represented in the flowcharts or otherwise described herein, e.g., an ordered listing of executable instructions that can be considered to implement logical functions, can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For the purposes of this description, a "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic device) having one or more wires, a portable computer diskette (magnetic device), a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via for instance optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner if necessary, and then stored in a computer memory.
It should be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. If implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.
It will be understood by those skilled in the art that all or part of the steps carried by the method for implementing the above embodiments may be implemented by hardware related to instructions of a program, which may be stored in a computer readable storage medium, and when the program is executed, the program includes one or a combination of the steps of the method embodiments.
In addition, functional units in the embodiments of the present invention may be integrated into one processing module, or each unit may exist alone physically, or two or more units are integrated into one module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. The integrated module, if implemented in the form of a software functional module and sold or used as a stand-alone product, may also be stored in a computer readable storage medium.
The storage medium mentioned above may be a read-only memory, a magnetic or optical disk, etc. Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (7)
1. An SWP host interface circuit, comprising:
an SWP host interface;
the voltage pulse transmitting unit is connected with the SWP main interface and used for generating two paths of first digital modulation signals and second digital modulation signals with different edges according to an initial digital modulation signal and respectively controlling the SWP main interface to send voltage pulse modulation signals to the SWP slave interface based on the first digital modulation signals and the second digital modulation signals;
the current receiving unit is respectively connected with the SWP main interface and the voltage pulse transmitting unit and is used for receiving a current modulation signal sent by the SWP slave interface from the SWP main interface based on a current threshold when the SWP main interface sends the voltage pulse modulation signal;
a receiving threshold adjusting unit connected to the current receiving unit, the receiving threshold adjusting unit being configured to adjust the current threshold;
an electrostatic protection unit, comprising: a first diode, a second diode and a first resistor; one end of the first resistor is connected with the SWP main interface, the other end of the first resistor is respectively connected with the anode of the first diode, the cathode of the second diode, the voltage pulse transmitting unit and the current receiving unit, the cathode of the first diode is connected with a power supply end, and the anode of the second diode is connected with a ground end;
the voltage pulse transmitting unit includes: the circuit comprises a first buffer, a signal processor, a first PMOS transistor, a first NMOS transistor and a second resistor; the input end of the first buffer is used for receiving an initial digital modulation signal, the output end of the first buffer is connected with the input end of the signal processor, the first output end of the signal processor is connected with the grid electrode of the first PMOS transistor, the second output end of the signal processor is connected with the grid electrode of the first NMOS transistor, the drain electrode of the first PMOS transistor is connected with one end of the second resistor, the other end of the second resistor is respectively connected with the drain electrode of the first NMOS transistor, the anode of the first diode and the current receiving unit, the source electrode of the first PMOS transistor is connected with a power supply end, and the source electrode of the first NMOS transistor is connected with the ground end; the signal processor is used for controlling the first output end to output a first digital modulation signal according to the output signal of the first buffer, and controlling the first PMOS transistor to be switched on and off through the first digital modulation signal; and the second output end is controlled to output a second digital modulation signal according to the output signal of the first buffer, and the first NMOS transistor is controlled to be switched on and switched off through the second digital modulation signal.
2. The circuit of claim 1, wherein the current receiving unit comprises: a second PMOS transistor, a third resistor, a delay, a comparator, a D flip-flop, and a second buffer,
the gate of the second PMOS transistor is connected with the ground, the source of the second PMOS transistor is connected with the source of the first PMOS transistor, the drain of the second PMOS transistor is connected with one end of the third resistor, the positive input end of the comparator is respectively connected with the other end of the third resistor and the receiving threshold adjusting unit, the negative input end of the comparator is connected with the positive electrode of the first diode, the output end of the comparator is connected with the D input end of the D trigger, the input end of the delayer is connected with the first output end of the signal processor, the output end of the delayer is connected with the CK input end of the D trigger, and the output end of the D trigger is connected with the input end of the second buffer.
3. The circuit of claim 2, wherein the reception threshold adjusting unit comprises: a second NMOS transistor, a third NMOS transistor, a fourth NMOS transistor, a fifth NMOS transistor, a sixth NMOS transistor, a seventh NMOS transistor, an eighth NMOS transistor, a ninth NMOS transistor, and a tenth NMOS transistor; wherein the content of the first and second substances,
a gate of the second NMOS transistor, a gate of the third NMOS transistor, a gate of the fourth NMOS transistor, a gate of the fifth NMOS transistor, a gate of the sixth NMOS transistor, and a drain of the second NMOS transistor are respectively connected to a reference current input terminal, a gate of the seventh NMOS transistor, a gate of the eighth NMOS transistor, a gate of the ninth NMOS transistor, and a gate of the tenth NMOS transistor are respectively connected to a current threshold adjustment terminal, a source of the second NMOS transistor, a source of the third NMOS transistor, a source of the fourth NMOS transistor, a source of the fifth NMOS transistor, and a source of the sixth NMOS transistor are respectively connected to ground, a drain of the third NMOS transistor is connected to a source of the seventh NMOS transistor, and a drain of the fourth NMOS transistor is connected to a source of the eighth NMOS transistor, the drain of the fifth NMOS transistor is connected to the source of the ninth NMOS transistor, the drain of the sixth NMOS transistor is connected to the source of the tenth NMOS transistor, and the drain of the seventh NMOS transistor, the drain of the eighth NMOS transistor, the drain of the ninth NMOS transistor, and the drain of the tenth NMOS transistor are respectively connected to the positive input end of the comparator;
the receiving threshold adjusting unit is specifically configured to adjust the current threshold through the adjusting terminal of the current threshold.
4. The circuit of any of claims 1-3, further comprising:
and the digital demodulation unit is connected with the output end of the current receiving unit and is used for demodulating the output signal output by the current receiving unit so as to analyze the data sent by the SWP from the interface.
5. The circuit according to claim 3, wherein the current threshold is adjusted within a range of 50uA to 750uA, and the accuracy of the adjustment of the current threshold is 50 uA/bit.
6. The circuit of claim 3, wherein the magnitude of the current threshold is 400uA ± 50 uA.
7. A terminal, characterized in that it comprises a SWP master interface circuit according to any of claims 1-6.
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| CN202110133121.3A CN112448709B (en) | 2021-02-01 | 2021-02-01 | SWP main interface circuit and terminal |
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| CN112448709B true CN112448709B (en) | 2021-05-18 |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104091192A (en) * | 2014-06-16 | 2014-10-08 | 华中科技大学 | Interface circuit of CLF chip in SWP protocol |
| CN111835334A (en) * | 2019-12-20 | 2020-10-27 | 北京紫光青藤微系统有限公司 | Automatic calibration SWP slave interface circuit |
| CN112118004A (en) * | 2020-11-19 | 2020-12-22 | 四川科道芯国智能技术股份有限公司 | SWP interface circuit and terminal |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| DE102016100809A1 (en) * | 2015-04-14 | 2016-10-20 | Samsung Electronics Co. Ltd. | Nahfeldkommunikationsbaugruppe and portable device containing the same |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104091192A (en) * | 2014-06-16 | 2014-10-08 | 华中科技大学 | Interface circuit of CLF chip in SWP protocol |
| CN111835334A (en) * | 2019-12-20 | 2020-10-27 | 北京紫光青藤微系统有限公司 | Automatic calibration SWP slave interface circuit |
| CN112118004A (en) * | 2020-11-19 | 2020-12-22 | 四川科道芯国智能技术股份有限公司 | SWP interface circuit and terminal |
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