Integrated circuit, electronic device, and communication system

Abstract

Embodiments of the present application disclose an integrated circuit, an electronic device, and a communication system, which solve the problem of a proximity integrated circuit causing an electromagnetic disturbance in a proximity coupling device. The specific solution involves providing an integrated circuit, the integrated circuit comprising a bridge rectifier, a direct current limiter, and a first processor. Two input ends of the bridge rectifier are used to be coupled to two ends of an antenna, and a positive output end of the bridge rectifier is coupled to an input end of the direct current limiter. A negative output end of the bridge rectifier and an output end of the direct current limiter are coupled to an analog grounding end. A power supply end of the first processor is coupled to the input end of the direct current limiter, and a grounding end of the first processor is coupled to the output end of the direct current limiter.

Description

Integrated circuit, electronic device and communication system

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on March 26, 2024, with application number 202410359367.6 and application name “An integrated circuit, electronic device and communication system”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of radio frequency identification technology, and in particular to an integrated circuit, an electronic device, and a communication system. Background Art

[0003] Proximity integrated circuits are used for contactless data transmission and identification, enabling communication with proximity coupling devices (PCDs). These ICs consist of a coupled antenna and processor. When the processor performs periodic calculations, it generates a periodically varying current, and the antenna transmits an electromagnetic wave signal corresponding to this current. When the antenna in the PCD receives this electromagnetic wave signal, it generates electromagnetic interference (EMD) in the PCD, causing it to misreceive data or transmit data incorrectly.

[0004] How to prevent proximity integrated circuits from generating electromagnetic interference to adjacent coupled devices has become an urgent problem that needs to be solved. Summary of the Invention

[0005] The embodiments of the present application provide an integrated circuit, an electronic device, and a communication system, which solve the problem of electromagnetic interference generated by a proximity integrated circuit on a proximity-coupled device.

[0006] To achieve the above objectives, the present invention adopts the following technical solutions:

[0007] According to a first aspect of an embodiment of the present application, an integrated circuit is provided, which includes a rectifier bridge, a DC current limiter and a first processor. The two input ends of the rectifier bridge are used to couple with the two ends of the antenna, the positive output end of the rectifier bridge is coupled with the input end of the DC current limiter, the negative output end of the rectifier bridge and the output end of the DC current limiter are coupled with the analog ground end, the power supply end of the first processor is coupled with the input end of the DC current limiter, and the ground end of the first processor is coupled with the output end of the DC current limiter.

[0008] Based on this solution, when the current output by the first processor changes, the DC current limiter can maintain a stable current output from the positive output end of the rectifier bridge, so that the current flowing through the antenna will also remain stable. When the antenna sends an electromagnetic wave signal corresponding to the current flowing through the antenna, the intensity of the electromagnetic wave signal will be weak, thereby avoiding the electromagnetic wave signal from causing electromagnetic interference to nearby coupled devices.

[0009] In combination with the first aspect, in one possible implementation, the rectifier bridge is used to rectify the alternating current received by the antenna into direct current to provide power to the first processor, the DC current limiter is used to limit the direct current output by the rectifier bridge, and the first processor is used to perform periodic operations.

[0010] Based on this solution, the current output from the positive output end of the rectifier bridge is the sum of the current output by the first processor and the discharge current output by the DC current limiter. The DC current limiter is used to limit the DC power output by the rectifier bridge. When the current output by the first processor decreases, the discharge current output by the DC current limiter increases. When the current output by the first processor increases, the discharge current output by the DC current limiter decreases. This maintains a stable current output from the positive output end of the rectifier bridge, and the current flowing through the antenna will also remain stable. When the antenna sends an electromagnetic wave signal corresponding to the current, the intensity of the electromagnetic wave signal will be weak, thereby preventing the electromagnetic wave signal from causing electromagnetic interference to adjacent coupling devices.

[0011] In conjunction with the first aspect, in one possible implementation, a DC current limiter includes a first resistor, a second resistor, and a first transistor. A first end of the first resistor and a first end of the first transistor are coupled to an input end of the DC current limiter, a second end of the first resistor is coupled to a gate end of the first transistor, a first end of the second resistor is coupled to a second end of the first resistor, and a second end of the second resistor and a second end of the first transistor are coupled to an output end of the DC current limiter.

[0012] Based on this solution, when the structure of the DC current limiter is as described above, the frequency information of the output current of the first processor is the same as the frequency information of the discharge current output by the DC current limiter. The two currents change simultaneously and in opposite directions. When the current output by the first processor increases, the discharge current output by the DC current limiter decreases accordingly. When the current output by the first processor decreases, the discharge current output by the DC current limiter increases accordingly. Therefore, during the change of the current output by the first processor, the positive output end of the rectifier bridge can maintain a stable current output, so that the current flowing through the antenna will also remain stable. When the antenna sends an electromagnetic wave signal corresponding to the current, the intensity of the electromagnetic wave signal will be weak, thereby avoiding the electromagnetic wave signal from causing electromagnetic interference to nearby coupled devices.

[0013] In combination with the first aspect, in a possible implementation, the integrated circuit further includes a capacitor, a first end of the capacitor is coupled to the input end of the DC current limiter, and a second end of the capacitor is coupled to the output end of the DC current limiter.

[0014] Based on this solution, the current output by the first processor is filtered by a capacitor, thereby further reducing the fluctuation of the output current at the positive output end of the rectifier bridge. The current flowing through the antenna will also be more stable. When the antenna sends the electromagnetic wave signal corresponding to the current, the intensity of the electromagnetic wave signal will be weaker, thereby further avoiding the electromagnetic wave signal from causing electromagnetic interference to nearby coupled devices.

[0015] In combination with the first aspect, in a possible implementation, the integrated circuit further includes a limiter, wherein two input terminals of the limiter are used to couple with two ends of the antenna, and an output terminal of the limiter is coupled with an analog ground terminal.

[0016] Based on this solution, the voltage amplitude of the AC power generated after the antenna receives AC energy is limited by the limiter, thereby protecting other components in the integrated circuit and improving the reliability of the integrated circuit.

[0017] In conjunction with the first aspect, in one possible implementation, the limiter includes a first diode, a second diode, a third resistor, a second transistor, and a third transistor. The anode of the first diode and the anode of the second diode are respectively coupled to the two input terminals of the limiter, and the cathode of the first diode is coupled to the cathode of the second diode. One end of the third resistor is coupled to the cathode of the first diode, and the other end of the third resistor is coupled to the output terminal of the limiter. The first end of the second transistor and the first end of the third transistor are respectively coupled to the two input terminals of the limiter, the gate terminal of the second transistor and the gate terminal of the third transistor are coupled to the cathode of the first diode, and the second end of the second transistor and the second end of the third transistor are coupled to the output terminal of the limiter.

[0018] Based on this solution, when the structure of the limiter is as described above, when the amplitude of the AC power generated by the antenna receiving AC energy exceeds the voltage threshold, the AC power can be limited in both the positive half-cycle and the negative half-cycle of the AC power, thereby protecting the remaining components in the integrated circuit and improving the reliability of the integrated circuit.

[0019] In combination with the first aspect, in a possible implementation, the first processor is configured to continuously operate within a preset duration of each cycle, where the preset duration is less than a duration for the integrated circuit to send a complete data frame via the antenna.

[0020] Based on this solution, the first processor continues to operate within a preset duration of each cycle. The first processor will output a varying current within the preset duration, and the antenna will transmit an electromagnetic wave signal to the proximity-coupled device within the preset duration. Because the preset duration is less than the duration for the integrated circuit to transmit a complete data frame via the antenna, the proximity-coupled device cannot obtain a complete data frame based on the electromagnetic wave signal received within the preset duration and will discard the incomplete data frame. As a result, the electromagnetic wave signal will not generate electromagnetic interference on the proximity-coupled device.

[0021] In conjunction with the first aspect, in one possible implementation, the integrated circuit further includes a second processor coupled to the first processor, and the second processor is configured to send a control signal to the first processor, where the control signal is configured to control the preset duration.

[0022] Based on this solution, the second processor sends a control signal to the first processor, which is used to control a preset duration. As a result, the first processor continues to operate within the preset duration of each cycle, outputs a varying current within the preset duration, and transmits an electromagnetic wave signal to the proximity-coupled device within the preset duration. This preset duration is less than the time it takes for the integrated circuit to transmit a complete data frame via the antenna. If the proximity-coupled device cannot obtain a complete data frame based on the electromagnetic wave signal received within the preset duration, it will discard the incomplete data frame. This prevents the electromagnetic wave signal from causing electromagnetic interference to the proximity-coupled device.

[0023] A second aspect of an embodiment of the present application provides a control method for an integrated circuit, which is applied to an integrated circuit, wherein the integrated circuit includes a rectifier bridge and a first processor coupled to the rectifier bridge. The method includes: the first processor continues to run within a preset duration of each cycle, and the preset duration is less than the duration for the integrated circuit to send a complete data frame through an antenna.

[0024] In a possible embodiment, the integrated circuit may be an integrated circuit as described in the above-mentioned first aspect or any possible implementation manner of the first aspect.

[0025] In conjunction with the second aspect, in one possible implementation, the integrated circuit further includes a second processor coupled to the first processor. The method further includes: the second processor sending a control signal to the first processor, the control signal being used to control the preset duration.

[0026] According to a third aspect of an embodiment of the present application, an electronic device is provided, comprising an antenna and an integrated circuit coupled to the antenna, wherein the integrated circuit is an integrated circuit as described in the first aspect or any possible implementation of the first aspect.

[0027] In a possible embodiment, the type of the electronic device includes at least one of a proximity integrated circuit card, a mobile phone, a watch, a bracelet, or a car key. The embodiment of the present application does not limit the specific type of the electronic device.

[0028] In a possible embodiment, when the electronic device is a proximity integrated circuit card, the type of the proximity integrated circuit card may include at least one of a bank card, an ID card, a room card, or a passport. The embodiment of the present application does not limit the specific type of the proximity integrated circuit card.

[0029] According to a fourth aspect of an embodiment of the present application, a communication system is provided, which includes a proximity coupling device and an electronic device coupled to communicate with the proximity coupling device. The electronic device is an integrated circuit as described in the third aspect or any possible implementation of the third aspect.

[0030] The descriptions of the second to fourth aspects of this application can refer to the detailed description of the first aspect; and the beneficial effects described in the second to fourth aspects can refer to the analysis of the beneficial effects of the first aspect, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG1 is a schematic structural diagram of a proximity integrated circuit card;

[0032] FIG2 is a schematic diagram of an integrated circuit application scenario provided by an embodiment of the present application;

[0033] FIG3 is a schematic diagram of the structure of an integrated circuit provided in an embodiment of the present application;

[0034] FIG4 is a schematic diagram of the structure of another integrated circuit provided in an embodiment of the present application;

[0035] FIG5 is a frequency response diagram provided in an embodiment of the present application;

[0036] FIG6 is a schematic diagram of the structure of another integrated circuit provided in an embodiment of the present application;

[0037] FIG7 is a schematic diagram of a data frame structure provided in an embodiment of the present application. DETAILED DESCRIPTION

[0038] The following sections discuss the making and use of various embodiments in detail. However, it should be understood that many applicable inventive concepts provided herein can be implemented in a variety of specific contexts. The specific embodiments discussed are intended merely to illustrate specific ways to implement and use the present description and technology and are not intended to limit the scope of this application.

[0039] Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art.

[0040] Various circuits or other components may be described or referred to as being "configured to" perform one or more tasks. In this case, "configured to" is used to imply structure by indicating that the circuit / component includes structure (e.g., circuitry) that performs the one or more tasks during operation. Thus, even when a specified circuit / component is not currently operational (e.g., not turned on), the circuit / component may be referred to as being configured to perform the task. Circuits / components used with the phrase "configured to" include hardware, such as circuitry that performs an operation, etc.

[0041] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. In the present application, "at least one" refers to one or more, and "plurality" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: the existence of A alone, the existence of A and B at the same time, and the existence of B alone, where A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can represent: a, b, c, a and b, a and c, b and c or a, b and c, where a, b and c can be single or multiple. In addition, in the embodiments of the present application, words such as "first" and "second" do not limit the quantity and order.

[0042] In this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described in this application as "exemplary" or "for example" should not be construed as preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0043] Before introducing the embodiments of the present application, the technical terms and background technologies involved in the present application are first introduced.

[0044] Proximity coupling device: refers to a read / write device that uses inductive coupling to provide energy to a proximity card and control data exchange with the proximity card, such as a radio frequency identification (RFID) reader.

[0045] Electromagnetic interference: also known as electromagnetic disturbance, refers to various electromagnetic phenomena that may cause the performance of devices or equipment (systems) to degrade.

[0046] Low-dropout regulator (LDO): also known as low-dropout linear regulator or low-dropout regulator, is a linear DC regulator used to provide a stable DC voltage.

[0047] Public key encryption (PKE): also known as asymmetric (key) encryption, refers to an encryption method consisting of a corresponding pair of unique keys (i.e., a public key and a private key).

[0048] Metal-oxide-semiconductor field-effect transistor (MOSFET): can also be referred to as metal-oxide-semiconductor field-effect transistor, abbreviated as MOS.

[0049] FIG1 is a schematic diagram of the structure of a proximity integrated circuit card (PICC) 100. The PICC 100 includes an antenna 110, a rectifier bridge (also called a rectifier) ​​120, a first capacitor 130, a low-voltage dropout regulator 140, a second capacitor 150, a processor 160, and a limiter 170. Antenna 110 has two terminals coupled to the two input terminals of rectifier bridge 120, a positive output terminal of rectifier bridge 120 is coupled to one terminal of first capacitor 130, a negative output terminal of rectifier bridge 120 is coupled to analog ground (AGND), and the other terminal of first capacitor 130 is coupled to ground (GND). A first terminal of low-dropout regulator 140 is coupled to the positive output terminal of rectifier bridge 120, a second terminal of low-dropout regulator 140 is coupled to an analog ground terminal, a third terminal of low-dropout regulator 140 and one terminal of second capacitor 150 are coupled to an input terminal of processor 160, and the other terminal of second capacitor 150 is coupled to ground. Antenna 110 is also coupled to both ends of limiter 170.

[0050] Antenna 110 is used to couple with antenna 210 in proximity coupling device 200 to obtain data and AC energy transmitted by antenna 210. Rectifier bridge 120 is used to rectify the AC power generated by antenna 110 when receiving AC energy into DC power. Low-voltage dropout regulator 140 is used to stabilize this DC power to provide a stable DC voltage to processor 160. Limiter 170 is used to limit the amplitude of the AC voltage generated by antenna 110 when receiving AC energy, thereby protecting other components in proximity integrated circuit card 100. First capacitor 130 and second capacitor 150 are used to filter out AC power transmitted in the circuit. Both capacitors have a capacitance of 2 nanofarads (nF).

[0051] During electrical interference testing of the proximity IC card 100, it was discovered that when the proximity IC card 100 and the proximity coupling device 200 are not communicating (i.e., in a non-communication phase), if the processor 160 in the proximity IC card 100 performs periodic operations, a periodically varying current is output from the processor 160. Due to the small capacitance of the first capacitor 130 and the second capacitor 150, the current output by the processor 160 cannot be effectively filtered out. This current is transmitted to the antenna 110, which then transmits an electromagnetic wave signal corresponding to the current. If the proximity coupling device 200 is sensitive to electromagnetic wave signals or has not implemented electromagnetic interference suppression, when the antenna 210 in the proximity coupling device 200 receives this electromagnetic wave signal, the electromagnetic wave signal will generate electromagnetic interference to the proximity coupling device 200, resulting in erroneous reception or data transmission errors at the proximity coupling device 200, poor data transmission reliability, and a poor user experience.

[0052] As the operating frequency of the processor 160 in the proximity integrated circuit card 100 continues to increase (e.g., exceeding 13.56 megahertz (MHz)), the power consumption of the processor 160 also continues to increase. The current generated by the processor 160 during periodic operations is increasing, and the frequency of this current is also increasing. Because the first capacitor 130 and the second capacitor 150 in the proximity integrated circuit card 100 have relatively small capacitances, these two capacitors are almost ineffective against microsecond (μs)-level current jumps and are unable to effectively filter the current output by the processor 160. Consequently, the electromagnetic wave signal corresponding to this current transmitted by the antenna 110 in the proximity integrated circuit card 100 is generating electromagnetic interference with the proximity coupled device 200, which is an increasingly prominent issue. Therefore, preventing the proximity integrated circuit card 100 from generating electromagnetic interference with the proximity coupled device 200 has become an urgent issue that needs to be addressed.

[0053] In one possible embodiment, the capacitance of the first capacitor 130 and the second capacitor 150 can be increased to filter the current output by the processor 160, thereby preventing the proximity integrated circuit card 100 from generating electromagnetic interference with the proximity coupling device 200. However, as the capacitance of the capacitor increases, the volume of the capacitor also increases, and large capacitors cannot be installed in the proximity integrated circuit card 100.

[0054] In another possible embodiment, a voltage sensor, a clock stop frequency detector, and a clock stop frequency shifter (not shown in the figures) coupled in series may be added between the processor 160 and the antenna 110 in the proximity integrated circuit card 100. The voltage sensor is used to detect the voltage of the current generated when the processor 160 performs periodic operations. When the peak value of the voltage exceeds a preset voltage, the clock stop frequency detector is triggered to detect the frequency of the current and transmit the current frequency to the clock stop frequency shifter. The clock stop frequency shifter is used to shift the frequency of the current to a frequency outside the response frequency of the proximity coupled device 200 when the current frequency is determined to cause electromagnetic interference to the proximity coupled device 200. This prevents the electromagnetic wave signal corresponding to the current from causing electromagnetic interference to the proximity coupled device 200 when the antenna 110 transmits the electromagnetic wave signal.

[0055] However, the proximity integrated circuit card 100 obtains energy through the coupling between the antenna 110 and the antenna 210. The proximity integrated circuit card 100 is a contactless power supply system. The voltage value of the current generated when the processor 160 performs periodic operations is relatively small. A voltage sensor is used to detect the voltage of the current output by the processor 160, which places high requirements on the detection sensitivity of the voltage sensor. The detection sensitivity of the existing voltage sensor cannot meet the requirements.

[0056] Based on this, an embodiment of the present application provides an integrated circuit that can be used in a proximity integrated circuit card. The integrated circuit maintains a stable current output at the positive output end of the rectifier bridge through a DC current limiter to reduce the fluctuation of the current flowing through the antenna. When the antenna sends an electromagnetic wave signal corresponding to the current, the intensity of the electromagnetic wave signal will be weak, thereby preventing the proximity integrated circuit card from generating electromagnetic interference on nearby coupling devices.

[0057] As shown in FIG2 , it is a schematic structural diagram of an application scenario of an integrated circuit 300 provided in an embodiment of the present application.

[0058] In a possible embodiment, the integrated circuit 300 may be integrated into a chip.

[0059] In one possible embodiment, as shown in FIG2 , the integrated circuit 300 may be applied to an electronic device 400 and coupled to an antenna 410 in the electronic device 400 . The integrated circuit 300 may communicate with the proximity-coupled device 200 and obtain energy through the antenna 410 . In the following embodiments of the present application, an example in which the integrated circuit 300 is applied to the electronic device 400 and the electronic device 400 is used to communicate with the proximity-coupled device 200 is used for illustrative description.

[0060] Optionally, the type of the electronic device 400 may include at least one of a proximity integrated circuit card, a mobile phone, a watch, a bracelet or a car key, or may be other electronic devices that meet the near field communication (NFC) International Standardization Organization / International Electrotechnical Commission 14443 (ISO / IEC 14443) protocol. The embodiment of the present application does not limit the specific type of the electronic device 400.

[0061] Optionally, when the electronic device 400 is a proximity integrated circuit card, the type of the proximity integrated circuit card may include at least one of a bank card, an ID card, a room card or a passport. The embodiment of the present application does not limit the specific type of the proximity integrated circuit card.

[0062] In a possible embodiment, as shown in FIG. 2 , when the integrated circuit 300 is applied to an electronic device 400 , the electronic device 400 may be applied to a communication system 500 . The communication system 500 includes the electronic device 400 and a proximity coupling device 200 coupled to communicate with the electronic device 400 .

[0063] As shown in FIG3 , a schematic diagram of the structure of an integrated circuit 300 provided in an embodiment of the present application is shown. The integrated circuit 300 includes a rectifier bridge 310, a DC current limiter 320, and a first processor 330. The two input terminals of the rectifier bridge 310 are used to couple with the two ends of the antenna 410. The positive output terminal of the rectifier bridge 310 is coupled with the input terminal of the DC current limiter 320. The negative output terminal of the rectifier bridge 310 and the output terminal of the DC current limiter 320 are coupled with the analog ground terminal. The power supply terminal (also referred to as the voltage drain drain (VDD) terminal) of the first processor 330 is coupled with the input terminal of the DC current limiter 320. The ground terminal (also referred to as the voltage source sink (VSS) terminal) of the first processor 330 is coupled with the output terminal of the DC current limiter 320.

[0064] Antenna 410 is configured to couple with antenna 210 in proximity coupling device 200 to obtain data and AC energy transmitted by antenna 210. Rectifier bridge 310 is configured to rectify the AC power generated by antenna 410 into DC power to power first processor 330. DC current limiter 320 is configured to limit the DC power output from the positive output terminal of rectifier bridge 310. First processor 330 is configured to perform periodic operations.

[0065] Specifically, as can be understood from FIG3 , the current Irec outputted from the positive output terminal of the rectifier bridge 310 satisfies the following formula: Irec=Ic+Idm

[0066] Wherein, Ic represents the current output by the first processor 330 , and Idm represents the discharge current output by the DC current limiter 320 .

[0067] Continuing with FIG3 , when the current Ic output by the first processor 330 decreases, the voltage Vrec at the positive output of the rectifier bridge 310 will increase because the positive output terminal of the rectifier bridge 310 provides energy to the first processor 330 without sudden changes. This will increase the bleeder current Idm output by the DC current limiter 320, thus keeping the current Irec output by the positive output terminal of the rectifier bridge 310 stable. Consequently, the current Iant flowing through the antenna 410 will also remain stable. When the antenna 410 transmits an electromagnetic wave signal corresponding to the current Iant, the intensity of the electromagnetic wave signal will be relatively weak, thereby preventing the electromagnetic wave signal from causing electromagnetic interference to the proximity-coupled device 200.

[0068] Continuing with FIG3 , when the current Ic output by the first processor 330 increases, the voltage Vrec at the positive output of the rectifier bridge 310 will decrease because the positive output terminal of the rectifier bridge 310 provides energy to the first processor 330 without sudden changes. This will also reduce the bleeder current Idm output by the DC current limiter 320, thus keeping the current Irec output by the positive output terminal of the rectifier bridge 310 stable. Consequently, the current Iant flowing through the antenna 410 will also remain stable. When the antenna 410 transmits an electromagnetic wave signal corresponding to the current Iant, the intensity of the electromagnetic wave signal will be relatively weak, thereby preventing the electromagnetic wave signal from causing electromagnetic interference to the proximity-coupled device 200.

[0069] Therefore, when the electronic device 400 and the proximity-coupling device 200 are not communicating and are in a non-communication phase, the first processor 330 performs periodic operations, and the first processor 330 outputs a periodically changing current. The DC current limiter 320 can maintain a stable current output from the positive output end of the rectifier bridge 310, so that the current Iant flowing through the antenna 410 will also remain stable. When the antenna 410 transmits an electromagnetic wave signal corresponding to the current Iant, the intensity of the electromagnetic wave signal will be weak, thereby preventing the electromagnetic wave signal from generating electromagnetic interference on the proximity-coupling device 200.

[0070] In a possible embodiment, the first processor 330 performing periodic operations includes the first processor 330 performing periodic public key encryption operations.

[0071] In one possible embodiment, when the electronic device 400 is away from the proximity coupling device 200, or when the amount of tasks executed by the first processor 330 in the integrated circuit 300 decreases, the current Ic output by the first processor 330 decreases. When the electronic device 400 is close to the proximity coupling device 200, or when the amount of tasks executed by the first processor 330 in the integrated circuit 300 increases, the current Ic output by the first processor 330 increases.

[0072] In the integrated circuit 300 provided in the embodiment of the present application, when the current Ic output by the first processor 330 changes, the DC current limiter 320 can maintain a stable current Irec outputted from the positive output end of the rectifier bridge 310, so that the current Iant flowing through the antenna 410 will also remain stable. When the antenna 410 transmits an electromagnetic wave signal corresponding to the current Iant flowing through the antenna 410, the intensity of the electromagnetic wave signal will be relatively weak, thereby preventing the electromagnetic wave signal from causing electromagnetic interference to the adjacent coupling device 200.

[0073] In a possible embodiment, as shown in (a) of FIG4 , the DC current limiter 320 includes a first resistor R1 , a second resistor R2 , and a first transistor MOS1 . In the embodiment of the present application, the transistor is a metal oxide semiconductor field effect transistor as an example for illustrative description.

[0074] A first end of the first resistor R1 and a first end of the first transistor MOS1 are coupled to an input end of the DC current limiter 320 , a second end of the first resistor R1 is coupled to a gate end of the first transistor MOS1 , a first end of the second resistor R2 is coupled to a second end of the first resistor R1 , and a second end of the second resistor R2 and a second end of the first transistor MOS1 are coupled to an output end of the DC current limiter 320 .

[0075] The working principle of the DC current limiter 320 is described below.

[0076] As shown in FIG4(a), when the current Ic output by the first processor 330 decreases, the voltage Vrec at the positive output of the rectifier bridge 310 will increase because the energy provided to the first processor 330 by the positive output of the rectifier bridge 310 does not change suddenly. The resistance values ​​of the first resistor R1 and the second resistor R2 in the DC current limiter 320 remain unchanged, the voltage at the gate of the first transistor MOS1 will increase, and the discharge current Idm output by the first transistor MOS1 will increase, which will keep the current Irec output by the positive output of the rectifier bridge 310 stable. As a result, the current Iant flowing through the antenna 410 will also remain stable. When the antenna 410 transmits the electromagnetic wave signal corresponding to the current Iant, the intensity of the electromagnetic wave signal will be relatively weak, thereby preventing the electromagnetic wave signal from causing electromagnetic interference to the proximity coupling device 200.

[0077] Continuing with FIG4(a), when the current Ic output by the first processor 330 increases, the voltage Vrec at the positive output of the rectifier bridge 310 will decrease because the positive output of the rectifier bridge 310 provides energy to the first processor 330 without sudden changes. The resistance values ​​of the first resistor R1 and the second resistor R2 in the DC current limiter 320 remain unchanged, the voltage at the gate of the first transistor MOS1 will decrease, and the discharge current Idm output by the first transistor MOS1 will decrease, which will keep the current Irec output by the positive output of the rectifier bridge 310 stable. As a result, the current Iant flowing through the antenna 410 will also remain stable. When the antenna 410 transmits the electromagnetic wave signal corresponding to the current Iant, the intensity of the electromagnetic wave signal will be relatively weak, thereby preventing the electromagnetic wave signal from causing electromagnetic interference to the proximity coupling device 200.

[0078] Furthermore, the current Ic output by the first processor 330 satisfies the following formula: Ic=K×cos(2pi×fc×t)

[0079] Wherein, K is the amplitude of the sine wave corresponding to the output current Ic of the first processor 330, pi represents pi, fc is the fluctuation frequency of the output current when the first processor 330 operates periodically, and t represents time.

[0080] As shown in FIG4(a), the first end of the first resistor R1 and the second end of the second resistor R2 are coupled to a node L, and the voltage of the node is VL. As shown in FIG4(b), the first transistor MOS1 can be equivalent to a current source i and a resistor RM coupled in parallel. When the first transistor MOS1 is turned on, the discharge current Idm output by the DC current limiter 320 satisfies the following formula: Idm = V × gm × cos(2pi × fc × t)

[0081] Wherein, V represents the voltage difference between the voltage VL at the node L and the analog ground terminal, gm represents the transconductance of the first transistor MOS1, pi represents pi, fc represents the fluctuation frequency of the output current when the first processor 330 is periodically running, and t represents time.

[0082] According to the above two formulas, the frequency information of the current Ic output by the first processor 330 is the same as the frequency information of the bleeder current Idm output by the DC current limiter 320. The two currents change simultaneously and in opposite directions. When the current Ic output by the first processor 330 increases, the bleeder current Idm output by the DC current limiter 320 decreases accordingly. When the current Ic output by the first processor 330 decreases, the bleeder current Idm output by the DC current limiter 320 increases accordingly. Therefore, during the change of the current Ic output by the first processor 330, the positive output terminal of the rectifier bridge 310 can maintain a stable current Irec, so that the current Iant flowing through the antenna 410 will also remain stable. When the antenna 410 transmits an electromagnetic wave signal corresponding to the current Iant, the intensity of the electromagnetic wave signal will be weak, thereby preventing the electromagnetic wave signal from causing electromagnetic interference to the nearby coupling device 200.

[0083] For example, as shown in FIG5 , when the processor 160 in the proximity integrated circuit card 100 performs periodic operations and the operating frequency of the processor 160 is 13.56 MHz, the processor 160 outputs a periodically changing current, the antenna 110 transmits an electromagnetic wave signal corresponding to the current, and the proximity coupling device 200 receives an electromagnetic wave signal of 8.5 mV at 11.8 MHz and an electromagnetic wave signal of 8.2 mV at 15.2 MHz. When the first processor 330 in the integrated circuit 300 performs periodic operations at a frequency of 13.56 MHz, the first processor 330 outputs a periodically changing current. Since the DC current limiter 320 maintains a stable current Irec outputted from the positive output terminal of the rectifier bridge 310, the current Iant flowing through the antenna 410 also remains stable. When the antenna 410 transmits an electromagnetic wave signal corresponding to the current Iant flowing through the antenna 410, the proximity coupling device 200 receives an electromagnetic wave signal of 0.5 mV at 11.8 MHz and an electromagnetic wave signal of 0.6 mV at 15.2 MHz. It can be understood that when the integrated circuit 300 provided in the embodiment of the present application is applied to the electronic device 400, the amplitude of the electromagnetic wave signal sent by the antenna 410 is less than 0.7 mV. Compared with the amplitude of the electromagnetic wave signal sent by the antenna 110 in the proximity integrated circuit card 100, which is greater than 8 mV, the integrated circuit 300 provided in the embodiment of the present application can effectively reduce the amplitude of the electromagnetic wave signal sent by the antenna 410, thereby preventing the electromagnetic wave signal from causing electromagnetic interference to the proximity coupling device 200.

[0084] In a possible embodiment, as shown in (a) of Figure 4, the rectifier bridge 310 includes four diodes Da to Dd, the cathode of diode Da and the cathode of diode Db are coupled to the positive output terminal of the rectifier bridge 310, the anode of diode Da and the cathode of diode Dc are coupled to one input terminal of the rectifier bridge 310, the anode of diode Db and the cathode of diode Dd are coupled to the other input terminal of the rectifier bridge 310, and the anode of diode Dc and the anode of diode Dd are coupled to the negative output terminal of the rectifier bridge 310.

[0085] In the integrated circuit 300 provided in the embodiment of the present application, the frequency information of the current Ic output by the first processor 330 is the same as the frequency information of the bleeder current Idm output by the DC current limiter 320. The two currents change simultaneously and in opposite directions. When the current Ic output by the first processor 330 increases, the bleeder current Idm output by the DC current limiter 320 decreases accordingly. When the current Ic output by the first processor 330 decreases, the bleeder current Idm output by the DC current limiter 320 increases accordingly. Therefore, during the change of the current Ic output by the first processor 330, the positive output terminal of the rectifier bridge 310 can maintain a stable current Irec, and thus the current Iant flowing through the antenna 410 will also remain stable. When the antenna 410 transmits an electromagnetic wave signal corresponding to the current Iant, the intensity of the electromagnetic wave signal will be relatively weak, thereby preventing the electromagnetic wave signal from causing electromagnetic interference to the adjacent coupling device 200.

[0086] In one possible embodiment, as shown in FIG6 , the integrated circuit 300 further includes a capacitor C, a first end of the capacitor C being coupled to the input end of the DC current limiter 320, and a second end of the capacitor C being coupled to the output end of the DC current limiter 320. The capacitor C is used to filter the current Ic output by the first processor 330, thereby further reducing fluctuations in the output current Irec at the positive output end of the rectifier bridge 310. The current Iant flowing through the antenna 410 will also be more stable. When the antenna 410 transmits an electromagnetic wave signal corresponding to the current Iant, the intensity of the electromagnetic wave signal will be weaker, thereby further preventing the electromagnetic wave signal from causing electromagnetic interference to the adjacent coupling device 200.

[0087] The integrated circuit 300 provided in the embodiment of the present application filters the current Ic output by the first processor 330 through the capacitor C, thereby further reducing the fluctuation of the output current Irec at the positive output end of the rectifier bridge 310. The current Iant flowing through the antenna 410 will also be more stable. When the antenna 410 transmits the electromagnetic wave signal corresponding to the current Iant, the intensity of the electromagnetic wave signal will be weaker, thereby further preventing the electromagnetic wave signal from causing electromagnetic interference to the adjacent coupling device 200.

[0088] In a possible embodiment, as shown in FIG6 , the integrated circuit 300 further includes a limiter 340 , wherein two input terminals of the limiter 340 are coupled to two ends of the antenna 410 , and an output terminal of the limiter 340 is coupled to an analog ground terminal.

[0089] The limiter 340 is used to limit the voltage amplitude of the AC power generated by the antenna 410 after receiving AC energy, thereby protecting other components in the integrated circuit 300 and improving the reliability of the integrated circuit 300.

[0090] In one possible embodiment, as shown in FIG6 , the limiter 340 includes a first diode D1, a second diode D2, a third resistor R3, a second MOS transistor 2, and a third MOS transistor 3. The anode of the first diode D1 and the anode of the second diode D2 are respectively coupled to the two input terminals of the limiter 340, and the cathode of the first diode D1 and the cathode of the second diode D2 are coupled. One end of the third resistor R3 is coupled to the cathode of the first diode D1, and the other end of the third resistor R3 is coupled to the output terminal of the limiter 340. The first end of the second MOS transistor 2 and the first end of the third MOS transistor 3 are respectively coupled to the two input terminals of the limiter 340, the gate end of the second MOS transistor 2 and the gate end of the third MOS transistor 3 are coupled to the cathode of the first diode D1, and the second end of the second MOS transistor 2 and the second end of the third MOS transistor 3 are coupled to the output terminal of the limiter 340.

[0091] In conjunction with Figure 6 , taking the voltages at the gates of the second transistor MOS2 and the third transistor MOS3 as VR3 as an example, when the amplitude of the AC power generated by the antenna 410 receiving AC energy exceeds a voltage threshold, during the positive half-cycle of the AC power, the AC power is transmitted through the first diode D1 to the third resistor R3. VR3 will rise, the second transistor MOS2 will turn on, generating a bleeder current, and the voltage at the anode of the first diode D1 will decrease, thereby limiting the voltage input to the rectifier bridge 310. During the negative half-cycle of the AC power, the AC power is transmitted through the second diode D2 to the third resistor R3. VR3 will rise, the third transistor MOS2 will turn on, generating a bleeder current, and the voltage at the anode of the second diode D2 will decrease, thereby limiting the voltage input to the rectifier bridge 310. It will be understood that the limiter 340 can limit the AC power during both the positive and negative half-cycles of the AC power, thereby protecting the remaining components in the integrated circuit 300 and improving the reliability of the integrated circuit 300.

[0092] The integrated circuit 300 provided in the embodiment of the present application limits the voltage amplitude of the AC power generated by the antenna 410 after receiving AC energy through the limiter 340, thereby protecting the remaining components in the integrated circuit 300 and improving the reliability of the integrated circuit 300.

[0093] In one possible embodiment, although the integrated circuit 300 described above can reduce the strength of the electromagnetic wave signal transmitted by the antenna 410 when the current Ic output by the first processor 330 changes, if the proximity coupling device 200 is sensitive to electromagnetic wave signals, the electromagnetic wave signal transmitted by the antenna 410 may still cause electromagnetic interference to the proximity coupling device 200. To address this issue, the integrated circuit 300 provided in this embodiment of the application limits the operating time of the first processor 330, thereby further reducing the possibility of the integrated circuit 300 generating electromagnetic interference to the proximity coupling device 200.

[0094] Specifically, the first processor 330 is configured to continuously operate within a preset duration of each cycle, where the preset duration is less than the duration for the integrated circuit 300 to transmit a complete data frame via the antenna 410. The preset duration is related to the operating frequency of the first processor 330 and the specific length of a complete data frame, and the embodiment of the present application does not limit the specific value of the preset duration.

[0095] The above-mentioned preset duration can also be understood as the duration of the integrated circuit 300 sending an incomplete data frame through the antenna 410. The incomplete data frame refers to a data frame that is missing compared to a complete data frame.

[0096] In a possible embodiment, an incomplete data frame may be a data frame that is missing at least one byte compared to a complete data frame. The embodiment of the present application does not limit the specific lengths of the complete data frame and the incomplete data frame. In the following embodiments of the present application, an incomplete data frame that is missing one byte compared to a complete data frame is used as an example for illustrative explanation.

[0097] For example, taking a complete data frame including 4 bytes as an example, an incomplete data frame may be a data frame including 3 bytes.

[0098] In a possible embodiment, the first processor 330 continuously operates within a preset duration of each cycle, and consumes low power or stops operating during a non-preset duration other than the preset duration of each cycle.

[0099] In a possible embodiment, the non-preset duration is greater than or equal to the duration for the integrated circuit 300 to send a byte through the antenna 410. The embodiments of the present application do not limit this. In the following embodiments of the present application, the non-preset duration is equal to the duration for the integrated circuit 300 to send a byte through the antenna 410 as an example for illustrative explanation.

[0100] For example, as shown in FIG7 , a complete data frame includes four bytes, the first byte of which is called the start of frame (SOF), and the second to fourth bytes are B1 to B3, respectively. An incomplete data frame includes the first byte SOF, the second byte B1, and the third byte B2. The preset duration is the duration for the integrated circuit 300 to transmit the incomplete data frame via the antenna 410, and the non-preset duration is the duration for the integrated circuit 300 to transmit the fourth byte B3 via the antenna 410. When the first processor 330 continues to operate within the preset duration and stops operating within the non-preset duration, the first processor 330 will output a variable current within the preset duration and will not output a variable current within the non-preset duration. The antenna 410 will transmit an electromagnetic wave signal to the proximity coupling device 200 within the preset duration and will not transmit an electromagnetic wave signal to the proximity coupling device 200 within the non-preset duration. Because the preset duration is equal to the duration of an incomplete data frame sent by the integrated circuit 300 via the antenna 410, the incomplete data frame is missing the fourth byte B3. Therefore, the proximity coupling device 200 cannot obtain a complete data frame based on the electromagnetic wave signal received within the preset duration. Instead, it obtains an incomplete data frame missing the fourth byte B3. The incomplete data frame fails verification, and the proximity coupling device 200 discards the incomplete data frame. As a result, the electromagnetic wave signal does not generate electromagnetic interference on the proximity coupling device 200.

[0101] In a possible embodiment, the first processor 330 may be a processor that implements periodic public key encryption operations through a hardware circuit. In this case, the first processor 330 may be called a public key encryption chip. Alternatively, the first processor 330 may be a processor that executes a public key encryption algorithm, such as a central processing unit (CPU). When the first processor 330 is a public key encryption chip, the first processor 330 is more efficient when performing periodic public key encryption operations. The embodiment of the present application does not limit the specific type of the first processor 330.

[0102] In one possible embodiment, when the first processor 330 is a public key encryption chip, a dummy operator can be inserted into the first processor 330 so that the first processor 330 operates at low power consumption within a non-preset time period, thereby ensuring that the first processor 330 does not output fluctuating current within a non-preset time period.

[0103] The integrated circuit 300 provided in the embodiment of the present application limits the operating time of the first processor 330, so that the first processor 330 continuously operates within a preset duration in each cycle. The first processor 330 outputs a varying current within the preset duration, and the antenna 410 transmits an electromagnetic wave signal to the proximity-coupled device 200 within the preset duration. Because the preset duration is shorter than the duration for the integrated circuit 300 to transmit a complete data frame via the antenna 410, the proximity-coupled device 200 cannot obtain a complete data frame from the electromagnetic wave signal received within the preset duration and discards the incomplete data frame. As a result, the electromagnetic wave signal does not cause electromagnetic interference to the proximity-coupled device 200.

[0104] In one possible embodiment, as shown in FIG6 , when the first processor 330 is a public key encryption chip, the integrated circuit 300 may further include a second processor 350 coupled to the first processor 330. The second processor 350 is configured to send a control signal to the first processor 330, where the control signal is used to control the preset duration.

[0105] In one possible embodiment, the second processor 350 may include a timer (TIM). When detecting that the first processor 330 starts running, the second processor 350 starts the timer. When the timer reaches a preset duration, the timer triggers the second processor 350 to generate an interrupt. The second processor 350 sends a control signal to the first processor 330, which controls the first processor 330 to stop running through the control signal, thereby controlling the preset duration of the first processor 330's operation.

[0106] In a possible embodiment, the second processor 350 may be a central processing unit.

[0107] In the integrated circuit 300 provided in an embodiment of the present application, the second processor sends a control signal to the first processor 330, which is used to control a preset duration. Thus, the first processor 330 continues to operate within the preset duration of each cycle, outputs a varying current within the preset duration, and the antenna 410 transmits an electromagnetic wave signal to the proximity coupling device 200 within the preset duration. The preset duration is less than the duration for the integrated circuit 300 to transmit a complete data frame via the antenna 410. If the proximity coupling device 200 cannot obtain a complete data frame based on the electromagnetic wave signal received within the preset duration, the incomplete data frame will be discarded, thereby preventing the electromagnetic wave signal from generating electromagnetic interference with the proximity coupling device 200.

[0108] An embodiment of the present application further provides an electronic device, which may be the electronic device 400 shown in FIG2 . The electronic device 400 includes an antenna 410 and an integrated circuit 300 coupled to the antenna 410 . The structure of the integrated circuit 300 is the structure of the integrated circuit 300 shown in any of FIG2 to FIG4 and FIG6 .

[0109] In a possible embodiment, the type of the electronic device 400 may include at least one of a proximity integrated circuit card, a mobile phone, a watch, a bracelet, or a car key. The embodiment of the present application does not limit the specific type of the electronic device 400.

[0110] Optionally, when the electronic device 400 is a proximity integrated circuit card, the type of the proximity integrated circuit card may include at least one of a bank card, an ID card, a room card or a passport. The embodiment of the present application does not limit the specific type of the proximity integrated circuit card.

[0111] Based on this, an embodiment of the present application further provides a communication system, which may be the communication system 500 shown in FIG2 . The communication system 500 includes a proximity coupling device 200 and an electronic device 400 coupled to and communicating with the proximity coupling device 200. The structure of the electronic device 400 is the structure of the electronic device 400 shown in any of FIG2 to FIG4 and FIG6 .

[0112] The above detailed description of the integrated circuit 300 and the analysis of its beneficial effects can be correspondingly referred to the electronic device 400 and the communication system 500 , and will not be further elaborated herein in the embodiments of the present application.

[0113] The above is only a specific embodiment of the present application, but the scope of protection of this application is not limited to this. Any changes or substitutions within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. An integrated circuit, characterized in that: The integrated circuit includes a rectifier bridge, a DC current limiter and a first processor; The two input ends of the rectifier bridge are used to couple with the two ends of the antenna, the positive output end of the rectifier bridge is coupled with the input end of the DC current limiter, the negative output end of the rectifier bridge and the output end of the DC current limiter are coupled with the analog ground end, and the first processor includes a power supply end and a ground end, the power supply end of the first processor is coupled with the input end of the DC current limiter, and the ground end of the first processor is coupled with the output end of the DC current limiter.

2. The integrated circuit according to claim 1, wherein: The rectifier bridge is used to rectify the alternating current received by the antenna into direct current to provide power to the first processor; The DC current limiter is used to limit the DC power output by the rectifier bridge; The first processor is used to perform periodic operations.

3. The integrated circuit according to claim 1 or 2, characterized in that The DC current limiter includes a first resistor, a second resistor and a first transistor; A first end of the first resistor and a first end of the first transistor are coupled to an input end of the DC current limiter, a second end of the first resistor is coupled to a gate end of the first transistor, a first end of the second resistor is coupled to a second end of the first resistor, and a second end of the second resistor and a second end of the first transistor are coupled to an output end of the DC current limiter.

4. The integrated circuit according to any one of claims 1 to 3, characterized in that The integrated circuit further includes a capacitor, a first end of the capacitor is coupled to the input end of the DC current limiter, and a second end of the capacitor is coupled to the output end of the DC current limiter.

5. The integrated circuit according to any one of claims 1 to 4, characterized in that The integrated circuit further includes a limiter, wherein two input terminals of the limiter are used to couple with two ends of the antenna, and an output terminal of the limiter is coupled with the analog ground terminal.

6. The integrated circuit according to claim 5, wherein: The limiter includes a first diode, a second diode, a third resistor, a second transistor and a third transistor; The anode of the first diode and the anode of the second diode are coupled to the two input terminals of the limiter respectively, and the cathode of the first diode and the cathode of the second diode are coupled; One end of the third resistor is coupled to the cathode of the first diode, and the other end of the third resistor is coupled to the output end of the limiter; The first end of the second transistor and the first end of the third transistor are respectively coupled to the two input ends of the limiter, the gate end of the second transistor and the gate end of the third transistor are coupled to the cathode of the first diode, and the second end of the second transistor and the second end of the third transistor are coupled to the output end of the limiter.

7. The integrated circuit according to any one of claims 1 to 6, characterized in that The first processor is configured to continuously operate within a preset duration of each cycle, where the preset duration is less than a duration for the integrated circuit to send a complete data frame via the antenna.

8. The integrated circuit according to claim 7, wherein: The integrated circuit further includes a second processor coupled to the first processor; The second processor is used to send a control signal to the first processor, where the control signal is used to control the preset duration.

9. An electronic device, characterized in that: The electronic device includes an antenna and an integrated circuit coupled to the antenna, wherein the integrated circuit is the integrated circuit according to any one of claims 1 to 8.

10. A communication system, characterized in that: The communication system includes a proximity coupling device and an electronic device coupled to communicate with the proximity coupling device, wherein the electronic device is the electronic device according to claim 9.

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