Tuning circuit, tuning method, tuning chip, and electronic device

Abstract

The present application provides a tuning circuit, a tuning method, a tuning chip, and an electronic device, which are applied to the technical field of integrated circuits, so as to solve the problems of high costs and large footprints of antenna tuning and calibration circuits. The tuning circuit comprises an input port, an output port, a first switch, a second switch, and an impedance adjustment circuit. The input port is coupled to the output port by means of the first switch. A first end of the impedance adjustment circuit is coupled to the input port by means of the second switch. A second end of the impedance adjustment circuit is grounded, and the impedance adjustment circuit comprises a third switch and a first impedance element which are connected in parallel between the first end and the second end of the impedance adjustment circuit. When a load connected to the output port needs to be tuned, the first switch can be closed, and the switch combination state of the second switch and the third switch can be adjusted. When impedance calibration is needed for an input circuit connected to the input port, the first switch can be opened, and the switch combination state of the second switch and the third switch can be adjusted.

Description

Tuning circuit, tuning method, tuning chip and electronic equipment

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on October 30, 2023, with application number 202311434986.9 and application name “A tuning circuit, tuning method, tuning chip and electronic device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of integrated circuit technology, and in particular to a tuning circuit, a tuning method, a tuning chip, and an electronic device. Background Art

[0003] When an object approaches or moves away from a terminal device equipped with an antenna, the impedance of the antenna will change. By detecting the impedance change in real time, the impedance of the tuned load (such as the antenna) is maintained in a conjugate matching state with the circuit transmission line, so that the output of the antenna obtains the maximum transmission power, thereby improving the over the air (OTA) performance of the antenna. Among them, in order to tune the load impedance, a corresponding tuning circuit is usually set, and the tuning circuit is controlled by the signal detected by the detection circuit for tuning. Affected by the consistency of the device and the routing, there are errors in the results of the impedance detection, which reduces the benefits of antenna tuning. In order to make the impedance detection results more accurate, thereby improving the benefits of antenna tuning, it is usually necessary to set a calibration circuit to calibrate the hardware circuit. However, the above method increases the cost and wiring area. Therefore, it is urgent to provide a solution to the above problems.

[0004] Summary of the Invention

[0005] The embodiments of the present application provide a tuning circuit, a tuning method, a tuning chip, and an electronic device to solve the problems of high cost and large wiring area caused by existing tuning circuits and calibration circuits.

[0006] In order to solve the above problems, this application provides the following implementation plans:

[0007] In a first aspect, a tuning circuit is provided, comprising an input port, an output port, a first switch, a second switch, and an impedance adjustment circuit. The first end of the first switch is coupled to the input port. The second end of the first switch is coupled to the output port. The first end of the second switch is coupled to the input port. The second end of the second switch is coupled to the first end of the impedance adjustment circuit. The second end of the impedance adjustment circuit is grounded, and the impedance adjustment circuit comprises a third switch and a first impedance element connected in parallel between the first and second ends of the impedance adjustment circuit. Using the above tuning circuit, when it is necessary to tune a load connected to the output port, the first switch can be closed, and the impedance of the load (e.g., an antenna) connected to the output port can be tuned by using multiple switch combinations of the second and third switches. When it is necessary to perform impedance calibration on an input circuit connected to the input port, the first switch can be opened, and then the impedance of the input circuit connected to the input port can be calibrated by using multiple switch combinations of the second and third switches. Based on this, only one tuning circuit needs to be set up to tune the load impedance and calibrate the impedance of the input circuit, without setting up an additional calibration circuit. This reduces the cost and wiring area while improving the convenience of load impedance tuning and input circuit calibration.

[0008] In some embodiments, the impedance adjustment circuit further includes a fourth switch and a second impedance element connected in parallel. The third switch and the first impedance element are connected in parallel and then grounded via the fourth switch and the second impedance element. This allows for tuning antenna impedance or impedance calibration of input circuits by providing a variety of impedances through various combinations of the third and fourth switches, thereby addressing diverse impedance tuning requirements.

[0009] In some embodiments, the impedance adjustment circuit further includes a fifth switch, a sixth switch, a third impedance element, and a fourth impedance element. The third switch and the first impedance element are connected in parallel and then connected to ground via the fifth switch and the third impedance element connected in series. Furthermore, the third switch and the first impedance element are connected in parallel and then connected to ground via the sixth switch and the fourth impedance element connected in series. In this manner, when tuning the load impedance or performing impedance calibration on the input circuit, various impedances can be provided by using various switch combinations of the third, fifth, and sixth switches, further accommodating a wider range of impedance tuning requirements.

[0010] In some embodiments, the tuning circuit further includes a first adjustable capacitor. A first terminal of the first adjustable capacitor is coupled to the second terminal of the first switch, and a second terminal of the first adjustable capacitor is coupled to the output port. This allows the first adjustable capacitor to be used to tune the load impedance according to actual needs, thereby meeting a wider range of impedance tuning requirements.

[0011] In some embodiments, the tuning circuit further includes a second adjustable capacitor connected in parallel with the first adjustable capacitor. Tuning by connecting the first adjustable capacitor and the second adjustable capacitor in parallel can also meet more impedance tuning requirements.

[0012] In some embodiments, the tuning circuit further includes seven switches and a first connection port. A first end of the seventh switch is coupled to the input port. A second end of the seventh switch is coupled to the first connection port. The first connection port is configured to connect to a fifth impedance element. In this manner, when tuning the load impedance, an additional impedance element can be provided at the input port, thereby meeting various impedance tuning requirements.

[0013] In some embodiments, the tuning circuit further includes an eighth switch and a second connection port. A first end of the eighth switch is coupled to the input port. A second end of the eighth switch is coupled to the second connection port. The second connection port is configured to connect to a sixth impedance element. In this manner, the impedance element provided at the input port can be expanded based on actual needs, making it easier for users to adjust the impedance element based on actual needs.

[0014] In some embodiments, the tuning circuit further includes a ninth switch and a third connection port. A first end of the ninth switch is coupled to the output port. A second end of the ninth switch is coupled to the third connection port. The third connection port is configured to connect to a seventh impedance element. In this manner, additional impedance elements can be provided at the output port to meet various impedance tuning requirements.

[0015] In some embodiments, the tuning circuit further includes a tenth switch and a fourth connection port. A first end of the tenth switch is coupled to the output port. A second end of the tenth switch is coupled to the fourth connection port. The fourth connection port is configured to connect to an eighth impedance element. Through this approach, the impedance element provided at the output port can be expanded based on actual needs, facilitating user adjustment of the impedance element based on actual needs.

[0016] In some embodiments, the tuning circuit further includes an eleventh switch and a twelfth switch. The first end of the eleventh switch is coupled to the first end of the impedance adjustment circuit. The second end of the eleventh switch and the first end of the twelfth switch are both coupled to the second end of the first adjustable capacitor. The second end of the twelfth switch is coupled to the output port. In this manner, if impedance calibration of the circuit preceding the first switch is required, the first switch can be opened, and various impedances can be provided by using various switch combinations of the second switch and the switches in the impedance adjustment circuit. If impedance calibration of the circuit preceding the twelfth switch is required, the twelfth switch can be opened, and various impedances can be provided by using various switch combinations of the eleventh switch and the switches in the impedance adjustment circuit. If antenna tuning is required, the first and twelfth switches can be closed, and various impedance tuning requirements can be provided by using various switch combinations of the eleventh switch and the switches in the impedance adjustment circuit, or by using various switch combinations of the second switch and the switches in the impedance adjustment circuit.

[0017] In some embodiments, the eleventh switch and the second switch are the same single-pole multi-throw switch. The first end of the eleventh switch and the second end of the second switch serve as a common terminal of the single-pole multi-throw switch. The second end of the eleventh switch serves as a first contact of the single-pole multi-throw switch. The first end of the second switch serves as a second contact of the single-pole multi-throw switch. This approach can reduce the number of switches, lowering costs and reducing wiring area.

[0018] In a second aspect, a tuning method is provided. The tuning method is applied to a tuning circuit, which includes an input port, an output port, a first switch, a second switch, and an impedance adjustment circuit. The first end of the first switch is coupled to the input port. The second end of the first switch is coupled to the output port. The first end of the second switch is coupled to the input port. The second end of the second switch is coupled to the first end of the impedance adjustment circuit. The second end of the impedance adjustment circuit is grounded, and the impedance adjustment circuit includes a third switch and a first impedance element connected in parallel between the first and second ends of the impedance adjustment circuit. When executing the circuit tuning method, the first switch can be closed. Then, the load connected to the output port is tuned through multiple switch combination states of the second switch and the third switch.

[0019] In some embodiments, the circuit tuning method may further include disconnecting the first switch during execution, and then performing impedance calibration on the input circuit connected to the input port through multiple switch combination states of the second switch and the third switch.

[0020] In a third aspect, a tuning chip is provided, which includes a substrate and a tuning circuit according to any one of the embodiments of the first aspect, disposed on the substrate.

[0021] In a fourth aspect, an electronic device is provided. The electronic device includes a radio frequency integrated circuit (RFIC), a bidirectional coupler, an antenna, and the tuning chip described in the second aspect. The RFIC includes an output terminal and a measurement terminal. The input terminal of the bidirectional coupler is coupled to the output terminal of the RFIC. The input port of the tuning chip is coupled to the output terminal of the bidirectional coupler. The output port of the tuning chip is coupled to the antenna. The coupling terminal of the bidirectional coupler is coupled to the measurement terminal of the RFIC.

[0022] The technical effects brought about by the above-mentioned second to fourth aspects and possible implementation methods can be found in the description of the technical effects brought about by the above-mentioned first aspect and possible implementation methods, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG1 is a schematic diagram of the structure of a circuit for antenna tuning and calibration;

[0024] FIG2 is a schematic diagram of another circuit structure for antenna tuning and calibration;

[0025] FIG3 is a schematic diagram of a bidirectional coupler provided in an embodiment of the present application;

[0026] FIG4 is a structural diagram of a tuning circuit provided in an embodiment of the present application;

[0027] FIG5 is a structural diagram of another tuning circuit provided in an embodiment of the present application;

[0028] FIG6 is a structural diagram of another tuning circuit provided in an embodiment of the present application;

[0029] FIG7 is a structural diagram of another tuning circuit provided in an embodiment of the present application;

[0030] FIG8 is a structural diagram of another tuning circuit provided in an embodiment of the present application;

[0031] FIG9 is a structural diagram of another tuning circuit provided in an embodiment of the present application;

[0032] FIG10 is a schematic diagram of a flow chart of a tuning method provided in an embodiment of the present application;

[0033] FIG11 is a schematic structural diagram of a tuning chip provided in an embodiment of the present application;

[0034] FIG12 is a schematic structural diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0035] 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.

[0036] In order to facilitate the clear description of the technical solutions of the embodiments of the present application, in the embodiments of the present application, words such as "first" and "second" are used to distinguish between identical or similar items with substantially the same functions and effects. Those skilled in the art will understand that words such as "first" and "second" do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit differences. At the same time, in the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or design schemes. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a concrete way for easy understanding.

[0037] When describing some embodiments, the terms "coupled" and "connected," and their derivatives, may be used. For example, when describing some embodiments, the term "connected" may be used to indicate that two or more components are in direct physical contact or point contact with each other. For another example, when describing some embodiments, the term "coupled" may be used to indicate that two or more components are in direct physical contact or electrical contact, or it may mean that two or more components are not in direct contact with each other but still cooperate or interact with each other. The embodiments disclosed herein are not necessarily limited to the contents herein.

[0038] The present application is described in detail below with reference to the accompanying drawings and embodiments:

[0039] Closed-loop antenna tuning primarily relies on impedance detection. Impedance is a physical quantity that represents the performance of a component or a circuit. It is the resistance to current flow in a circuit composed of resistors, inductors, and capacitors. Impedance, often represented by Z, is a complex number whose real part is resistance and whose imaginary part is reactance. When an object approaches or moves away from an electronic device equipped with an antenna, the antenna's impedance changes. By detecting the antenna's impedance changes in real time and tuning the antenna's impedance to maintain a conjugate match with the circuit's transmission line, the antenna's output can achieve maximum transmission power. As shown in Figure 1, to implement impedance detection and antenna impedance tuning, the electronic device 100 typically includes a radio frequency integrated circuit (IC) 110, a power amplifier (PA) 120, a bidirectional coupler 130, an attenuator 140, a tuning circuit 150, a calibration circuit 160, and an antenna 170. The RF output terminal Tx of the RFIC 110 is coupled to the input terminal a of the bidirectional coupler 130 via the power amplifier 120. The output terminal b of the bidirectional coupler 130 is then coupled to the antenna 170 through the tuning circuit 150 and the calibration circuit 160. In addition, the coupling end of the bidirectional coupler 130 (including the forward coupling end Fwr and the reverse coupling end Rev) is coupled to the input end of the attenuator 140 through the selection switch SW. The output end of the attenuator 140 is coupled to the measurement end MRx of the RF integrated circuit 110. Among them, after the RF signal is output through the RF output end Tx of the RF integrated circuit 110, it is first amplified by the power amplifier 120. Then, it passes through the bidirectional coupler 130, the tuning circuit 150 and the calibration circuit 160 in sequence and is output through the antenna 170. At the same time, the forward transmission signal detected by the forward coupling end Fwr of the bidirectional coupler 130 or the reverse transmission signal detected by the reverse coupling end Rev can be processed by the attenuator 140 and transmitted to the measurement end MRx of the RF integrated circuit 110. The RFIC 110 can calculate the reflection coefficient of the measurement terminal MRx (i.e., the value of the reverse transmission signal / forward transmission signal) based on the forward transmission signal and the reverse transmission signal. Finally, the reflection coefficient of the antenna 170 is calculated based on the reflection coefficient of the measurement terminal MRx, thereby obtaining the impedance state of the antenna 170. The tuning circuit 150 is controlled based on the impedance state to tune the impedance of the antenna 170.

[0040] In the above implementation process, the principle of the bidirectional coupler 130 is shown in FIG3. When the bidirectional coupler 130 is used, the reflection coefficient Γ of the antenna in The reflection coefficient Г of the measuring end MRx can be MRx , the coupling coefficient of the bidirectional coupler 130 (including the forward coupling coefficient S 31 and reverse coupling coefficient S 42), the isolation S between the input terminal a and the reverse coupling terminal Rev of the bidirectional coupler 130 41 , the isolation S between the output terminal b of the bidirectional coupler 130 and the forward coupling terminal Fwr 32 and the through channel insertion loss S of the bidirectional coupler 130 21 Through the reflection coefficient Г in The impedance state of the antenna can be obtained, and the impedance of the tuning circuit 150 can be tuned according to the impedance state. The specific calculation formula (1) is as follows:

[0041] Where a = S 41 / S 31 , b=S 21 ·S 42 / S 31 , c=S 21 ·S 32 / S 31 , a, b and c represent calculation parameters.

[0042] However, due to the influence of the impedance consistency of the device and the single board trace, the circuit impedance parameters fluctuate, causing errors in the impedance detection results, resulting in loss of antenna tuning gain, or even negative gain. Therefore, it is necessary to perform impedance calibration on the circuit through the calibration circuit 160. The impedance calibration process is the inverse operation of the impedance detection. in , the reflection coefficient Г of the measuring end MRx MRx When the S parameters of the bidirectional coupler are known, reverse calculation (including S 21 、S 31 、S 32 、S 41 and S 42 ), that is, the three parameters a, b and c are solved during the calibration process. When performing impedance calibration, it is necessary to provide at least three types of impedance states through the calibration circuit 160, so as to solve the three parameters a, b and c. As shown in Figure 1, in order to perform impedance calibration on the circuit, many calibration circuits 160 and tuning circuits 150 are set separately in the electronic device. Alternatively, as shown in Figure 2, the calibration circuit 160 is an external circuit. A detection point is provided between the tuning circuit 150 and the antenna 170, and the calibration circuit 160 is connected to the detection point A through a probe. In this way, the calibration circuit 160 can be set independently, which can better meet various calibration needs. However, both of the above methods require the additional provision of a calibration circuit 160, which increases the cost and wiring area.

[0043] To address the above-mentioned issues, as shown in FIG4 , an embodiment of the present application provides a tuning circuit 400. The tuning circuit 400 includes an input port RFin, an output port RFout, a first switch S1, a second switch S2, and an impedance adjustment circuit 410. The first end of the first switch S1 is coupled to the input port RFin; the second end of the first switch S1 is coupled to the output port RFout. The first end of the second switch S2 is coupled to the input port RFin. The second end of the second switch S2 is coupled to the first end of the impedance adjustment circuit 410. The second end of the impedance adjustment circuit 410 is grounded, and the impedance adjustment circuit 410 includes a third switch S3 and a first impedance element Z1 connected in parallel between the first and second ends of the impedance adjustment circuit 410. The first impedance element Z1 can be an element with stable impedance characteristics, and the impedance value of the first impedance element Z1 can be selected according to actual needs. The embodiment of the present application does not impose any specific restrictions on this.

[0044] In one example, when impedance calibration is required for an input circuit connected to the input port RFin, the first switch S1 can be disconnected, and then impedance calibration is performed on the input circuit connected to the input port RFin using multiple switch combinations of the second switch S2 and the third switch S3. When the first switch S1 is disconnected, the switch combinations of the second switch S2 and the third switch S3 are as follows:

[0045] 1) Turn off the second switch S2. At this time, the impedance adjustment circuit 410 only provides open-circuit impedance.

[0046] 2) Close the second switch S2 and open the third switch S3. At this time, the impedance provided by the impedance adjustment circuit 410 is Z1+Z s2 Among them, Z s2 is the impedance of the second switch S2; Z1 is the impedance of the first impedance element Z1.

[0047] 3) Close the second switch S2 and the third switch S3. At this time, the impedance provided by the impedance adjustment circuit 410 is Z s2 +Z1*Z s3 / (Z1+Z s3 ). Among them, Z s3 is the impedance of the third switch S3.

[0048] When performing impedance calibration, the antenna's reflection coefficient Г in and the reflection coefficient Г at the measuring end MRx It can be set to a known value. Through the above three impedance states and calculation formula (1), three calculation equations can be constructed to solve the three parameters a, b and c, thereby realizing impedance calibration of the input circuit connected to the input port RFin.

[0049] In one example, after impedance calibration is performed on the input circuit connected to the input port RFin, if the load connected to the output port RFout needs to be tuned, the first switch S1 can be closed, and the load connected to the output port RFout can be tuned through multiple switch combination states of the second switch S2 and the third switch S3. For example, when the first switch S1 is closed, the second switch S2 can be opened first. The corresponding reflection coefficient (i.e., the value of the reverse transmission signal / forward transmission signal) is calculated by the forward transmission signal detected by the forward coupling end Fwr of the bidirectional coupler and the reverse transmission signal detected by the reverse coupling end Rev. Then, the switch combination state of the second switch S2 and the third switch S3 is confirmed based on the reflection coefficient. Among them, when the first switch S1 is closed, the switch combination state of the second switch S2 and the third switch S3 can refer to the switch combination state when the impedance calibration of the input circuit is performed above, and the embodiments of the present application are not repeated here. In addition, the switch combination state of the second switch S2 and the third switch S3 can be selected according to the impedance state of the antenna. For example, the RF IC can determine the switch combination state of the second switch S2 and the third switch S3 by looking up a table. For example, the operator can use the reflection coefficient Γ of the measuring end to MRx The lookup table is constructed based on the tuning relationship between the switch combination state of the second switch S2 and the third switch S3. Then, the RF IC is used to detect the reflection coefficient Γ in real time. MRx The switch combination state of the second switch S2 and the third switch S3 is determined from the lookup table, and the switch states of the second switch S2 and the third switch S3 are controlled according to the switch combination state, thereby achieving impedance tuning of the antenna.

[0050] Through the above method, only one tuning circuit 400 needs to be set up to tune the load (such as an antenna) impedance and calibrate the input circuit, without setting up an additional calibration circuit. This reduces costs and wiring area while improving the convenience of antenna tuning and input circuit calibration.

[0051] In some embodiments, as shown in FIG5 , the impedance adjustment circuit 410 further includes a fourth switch S4 and a second impedance element Z2 connected in parallel. Specifically, after the third switch S3 and the first impedance element Z1 are connected in parallel, they are grounded through the fourth switch S4 and the second impedance element Z2 connected in parallel. In the above manner, when impedance calibration of the input circuit connected to the input port RFin is required, the first switch S1 can be disconnected, and then the impedance calibration of the input circuit connected to the input port RFin can be performed through multiple switch combination states of the second switch S2, the third switch S3, and the fourth switch S4. Specifically, when the first switch S1 is disconnected, the switch combination states of the second switch S2, the third switch S3, and the fourth switch S4 are as follows:

[0052] 1) Turn off the second switch S2. At this time, the impedance adjustment circuit 410 only provides open-circuit impedance.

[0053] 2) Close the second switch S2 and open the third switch S3 and the fourth switch S4. At this time, the impedance provided by the impedance adjustment circuit 410 is Z1+Z s2 +Z2. Among them, Z s2 is the impedance of the second switch S2; Z1 is the impedance of the first impedance element Z1; and Z2 is the impedance of the second impedance element Z2.

[0054] 3) Close the second switch S2 and the third switch S3, and open the fourth switch S4. At this time, the impedance provided by the impedance adjustment circuit 410 is Z2+Z s2 +Z1*Z s3 / (Z1+Z s3 ). Among them, Z s3 is the impedance of the third switch S3.

[0055] 4) Close the second switch S2 and the fourth switch S4, and open the third switch S3. At this time, the impedance provided by the impedance adjustment circuit 410 is Z1+Z s2 +Z2*Z s4 / (Z2+Z s4 ). Among them, Z s4 is the impedance of the fourth switch S4.

[0056] 5) Close the second switch S2, the third switch S3 and the fourth switch S4. At this time, the impedance provided by the impedance adjustment circuit 410 is Z s2 +Z1*Z s3 / (Z1+Z s3 )+Z2*Z s4 / (Z2+Z s4 ).

[0057] When performing impedance calibration, the antenna's reflection coefficient Г in and the reflection coefficient Г at the measuring end MRx It can be set to a known value. Three calculation equations can be constructed by any three of the five impedance states and calculation formula (1) to solve the three parameters a, b and c, thereby realizing impedance calibration of the input circuit connected to the input port RFin.

[0058] After impedance calibration is performed on the input circuit connected to the input port RFin, if it is necessary to tune the load connected to the output port RFout, the first switch S1 can be closed, and the load connected to the output port RFout can be tuned through multiple switch combination states of the second switch S2, the third switch S3, and the fourth switch S4. For example, when the first switch S1 is closed, the second switch S2 can be opened first. The corresponding reflection coefficient (i.e., the value of the reverse transmission signal / forward transmission signal) is calculated based on the forward transmission signal detected by the forward coupling end Fwr of the bidirectional coupler and the reverse transmission signal detected by the reverse coupling end Rev. Then, the switch combination state of the second switch S2, the third switch S3, and the fourth switch S4 is confirmed based on the reflection coefficient. Among them, when the first switch S1 is closed, the switch combination state of the second switch S2, the third switch S3, and the fourth switch S4 is the same as when the impedance calibration is performed on the input circuit connected to the input port RFin, and the embodiments of the present application are not described in detail here.

[0059] In the above implementation scheme, the impedance adjustment circuit 410 in Figure 5 is only an example provided in the embodiment of the present application. When it is implemented specifically, it can be further expanded with reference to the parallel connection mode of the fourth switch S4 and the second impedance element Z2. The embodiment of the present application will not be described in detail here.

[0060] In some embodiments, based on the tuning circuit 400 of FIG. 5 , as shown in FIG. 6 , the tuning circuit 400 further includes a first adjustable capacitor C1. A first end of the first adjustable capacitor C1 is coupled to a second end of the first switch S1. A second end of the first adjustable capacitor C1 is coupled to the output port RFout. When impedance tuning of a load (e.g., an antenna) is required, in addition to tuning via the impedance adjustment circuit 410, the impedance of the load can also be tuned by adjusting the first adjustable capacitor C1.

[0061] Optionally, the tuning circuit 400 further includes a second adjustable capacitor C2 connected in parallel with the first adjustable capacitor C1. The first adjustable capacitor C1 and the second adjustable capacitor C2 can form a parallel tuning circuit to meet more tuning requirements.

[0062] In some embodiments, as shown in FIG7 , the tuning circuit 400 may further include a seventh switch S7 and a first connection port P1. The first end of the seventh switch S7 is coupled to the input port RFin. The second end of the seventh switch S7 is coupled to the first connection port P1. The first connection port P1 is used to connect a fifth impedance element. The fifth impedance element may be a resistor, a capacitor, an inductor, or the like, and may be selected based on the user's specific needs. In this manner, when performing impedance tuning on a load, an additional impedance element may be provided at the input port RFin, thereby providing more impedance tuning requirements.

[0063] Furthermore, the impedance element connected to the input port RFin can be further expanded. For example, as shown in Figure 7, the above-mentioned tuning circuit 400 can also include an eighth switch S8 and a second connection port P2. The first end of the eighth switch S8 is coupled to the input port RFin. The second end of the eighth switch S8 is coupled to the second connection port P2. The second connection port P2 is used to connect a sixth impedance element. The sixth impedance element can also be a resistor, a capacitor, an inductor, etc., and can be selected according to the user's usage requirements during specific use. In addition, the fifth impedance element and the sixth impedance element can be the same or different, and the embodiments of the present application do not impose specific restrictions on this.

[0064] The above implementation is only an example given in the embodiment of the present application, and the impedance element connected to the input port RFin can also be expanded in a similar manner.

[0065] In some embodiments, as shown in FIG7 , the tuning circuit 400 may further include a ninth switch S9 and a third connection port P3. A first end of the ninth switch S9 is coupled to the output port RFout. A second end of the ninth switch S9 is coupled to the third connection port P3. The third connection port P3 is configured to connect to a seventh impedance element. In this manner, when performing impedance tuning on a load, an additional impedance element may be provided at the output port RFout, thereby meeting various impedance tuning requirements.

[0066] Furthermore, the impedance element connected to the output port RFout can also be expanded. For example, as shown in Figure 7, the above-mentioned tuning circuit 400 can also include a tenth switch S10 and a fourth connection port P4. The first end of the tenth switch S10 is coupled to the output port RFout. The second end of the tenth switch S10 is coupled to the fourth connection port P4. The fourth connection port P4 is used to connect the eighth impedance element. In the above implementation process, the seventh impedance element and the eighth impedance element can be the same or different. In addition, the fifth to eighth impedance elements can also be selected according to actual needs, and the embodiments of the present application do not impose specific restrictions on this.

[0067] Of course, the above implementation scheme is only an example given in the embodiment of the present application, and the impedance element connected to the output port RFout can also be expanded in a similar manner.

[0068] In some embodiments, as shown in FIG8 , the tuning circuit 400 may further include an eleventh switch S11 and a twelfth switch S12. The first end of the eleventh switch S11 is coupled to the first end of the impedance adjustment circuit 410. The second end of the eleventh switch S11 and the first end of the twelfth switch S12 are both coupled to the second end of the first adjustable capacitor C1. The second end of the twelfth switch S12 is coupled to the output port RFout. In this manner, if impedance calibration of the circuit preceding the first switch S1 is required, the first switch S1 can be disconnected, and various combinations of the second switch S2 and the switches in the impedance adjustment circuit 410 can be used to provide various impedances, thereby performing impedance calibration of the circuit preceding the first switch S1 based on the detected reflection coefficient. If impedance calibration of the circuit preceding the twelfth switch S12 is required, the twelfth switch S12 can be disconnected, and various combinations of the eleventh switch S11 and the switches in the impedance adjustment circuit 410 can be used to provide various impedances, thereby performing impedance calibration of the circuit preceding the twelfth switch S12 based on the detected reflection coefficient. If antenna tuning is required, the first switch S1 and the twelfth switch S12 can be closed, and various impedances can be provided by various switch combinations of the eleventh switch S11 and the switches in the impedance adjustment circuit 410; alternatively, various impedances can be provided by various switch combinations of the second switch S2 and the switches in the impedance adjustment circuit 410, thereby meeting more impedance tuning requirements. The switch combinations of the eleventh switch S11 and the switches in the impedance adjustment circuit 410, or the switch combinations of the second switch S2 and the switches in the impedance adjustment circuit 410, can be combined in a manner similar to that described in FIG. 4 or FIG. 5 above, and are not described in detail in this embodiment of the present application.

[0069] Furthermore, to reduce component usage, cost, and wiring area, the eleventh switch S11 and the second switch S2 can be the same single-pole multi-throw switch. This single-pole multi-throw switch includes a common terminal and multiple switchable contacts. The first terminal of the eleventh switch S11 and the second terminal of the second switch S2 serve as the common terminal of the single-pole multi-throw switch. The second terminal of the eleventh switch S11 serves as the first contact of the single-pole multi-throw switch. The first terminal of the second switch S2 serves as the second contact of the single-pole multi-throw switch. The first and second contacts can be any two different contacts in the single-pole multi-throw switch. For example, to improve switch utilization, the single-pole multi-throw switch can be a single-pole double-throw switch.

[0070] In an example, a switch S0 may be further provided in the branch where the second adjustable capacitor C2 is located in each of the above embodiments, so that whether to connect the second adjustable capacitor C2 can be selected according to actual needs during tuning.

[0071] In the above implementation process, the embodiment shown in FIG8 is only an example provided by the embodiment of the present application. Any of the embodiments shown in FIG4 to FIG7 can choose to set the eleventh switch S11 and the twelfth switch S12 in the manner shown in FIG8. The embodiment of the present application will not be described in detail here. In addition, the above embodiments can be combined and expanded, and the embodiment of the present application does not impose specific limitations on this.

[0072] In some embodiments, as shown in FIG9 , the tuning circuit 400 may further include a fifth switch S5, a sixth switch S6, a third impedance element Z3, and a fourth impedance element Z4. The third switch S3 and the first impedance element Z1 are connected in parallel and then connected to ground via the fifth switch S5 and the third impedance element Z3 connected in series. Furthermore, the third switch S3 and the first impedance element Z1 are connected in parallel and then connected to ground via the sixth switch S6 and the fourth impedance element Z4 connected in series.

[0073] In the above manner, when impedance calibration of the input circuit connected to the input port RFin is required, the first switch S1 can be disconnected, and then impedance calibration of the input circuit connected to the input port RFin can be performed through various switch combinations of the second switch S2, the third switch S3, the fifth switch S5, and the sixth switch S6. When the first switch S1 is disconnected, the switch combinations of the second switch S2, the third switch S3, the fifth switch S5, and the sixth switch S6 are as follows:

[0074] 1) Turn off the second switch S2. At this time, the impedance adjustment circuit 410 only provides open-circuit impedance.

[0075] 2) Close the second switch S2, open the third switch S3 and the sixth switch S6, and close the fifth switch S5. At this time, the impedance provided by the impedance adjustment circuit 410 is Z1+Z s2 +Z s5 +Z3. Among them, Z s2 is the impedance of the second switch S2; Z1 is the impedance of the first impedance element Z1; Z3 is the impedance of the third impedance element Z3; Z s5 is the impedance of the fifth switch S5.

[0076] 3) Close the second switch S2, open the third switch S3 and the fifth switch S5, and close the sixth switch S6. At this time, the impedance provided by the impedance adjustment circuit 410 is Z1+Z s2 +Z s6 +Z4. Wherein, Z4 is the impedance of the fourth impedance element Z4; Z s6 is the impedance of the sixth switch S6.

[0077] 4) Close the second switch S2, open the third switch S3, and close the fifth switch S5 and the sixth switch S6. At this time, the impedance provided by the impedance adjustment circuit 410 is Z1+Zs2 +(Z s5 +Z3)*(Z s6 +Z4) / ((Z s5 +Z3)+(Z s6 +Z4)).

[0078] 5) Close the second switch S2, close the third switch S3, close the fifth switch S5 and the sixth switch S6. At this time, the impedance provided by the impedance adjustment circuit 410 is Z s2 +Z1*Z s3 / (Z1+Z s3 )+(Z s5 +Z3)*(Z s6 +Z4) / ((Z s5 +Z3)+(Z s6 +Z4)).

[0079] 6) Close the second switch S2, close the third switch S3, close the fifth switch S5, and open the sixth switch S6. At this time, the impedance provided by the impedance adjustment circuit 410 is Z s2 +Z1*Z s3 / (Z1+Z s3 )+Z s5 +Z3.

[0080] 7) Close the second switch S2, close the third switch S3, close the fifth switch S5, and open the sixth switch S6. At this time, the impedance provided by the impedance adjustment circuit 410 is Z s2 +Z1*Z s3 / (Z1+Z s3 )+Z s6 +Z4.

[0081] When performing impedance calibration, the antenna's reflection coefficient Г in and the reflection coefficient Г at the measuring end MRx It can be set to a known value. Three calculation equations can be constructed by using any three of the seven impedance states and calculation formula (1) to solve the three parameters a, b, and c, thereby realizing impedance calibration of the input circuit connected to the input port RFin.

[0082] After impedance calibration is performed on the input circuit connected to the input port RFin, if it is necessary to tune the load connected to the output port RFout, the first switch S1 can be closed, and the load connected to the output port RFout can be tuned through multiple switch combination states of the second switch S2, the third switch S3, the fifth switch S5, and the sixth switch S6. For example, when the first switch S1 is closed, the second switch S2 can be opened first. The corresponding reflection coefficient (i.e., the value of the reverse transmission signal / forward transmission signal) is calculated by the forward transmission signal detected by the forward coupling end Fwr of the bidirectional coupler and the reverse transmission signal detected by the reverse coupling end Rev. Then, the switch combination state of the second switch S2, the third switch S3, the fifth switch S5, and the sixth switch S6 is confirmed based on the reflection coefficient. Among them, when the first switch S1 is closed, the switch combination state of the second switch S2, the third switch S3, the fifth switch S5, and the sixth switch S6 is the same as when the impedance calibration is performed on the input circuit connected to the input port RFin, and the embodiments of the present application are not described in detail here.

[0083] Furthermore, the tuning circuit 400 in FIG. 9 can be expanded or combined with reference to any one of the implementations in FIG. 6 to FIG. 8 , and the embodiment of the present application does not impose any specific limitation on this.

[0084] In some embodiments, as shown in FIG10 , the present application also provides a tuning method applied to the tuning circuit 400 . The method may be executed by a processor, and the specific execution process is as follows:

[0085] S101: Turn off the first switch.

[0086] The first switch S1 can be controlled by a control signal sent by a processor in the radio frequency IC, or by a control signal sent by a processor connected to the radio frequency IC, and the embodiment of the present application does not impose specific restrictions on this. The above-mentioned processor can be a central processing unit (CPU), a general-purpose processor, a network processor (NP), a field programmable gate array (FPGA), an application-specific integrated circuit (ASIC), or a system on chip (SoC), or any combination thereof. The embodiment of the present application does not impose specific restrictions on this.

[0087] S102: performing impedance calibration on an input circuit connected to the input port through a plurality of switch combination states of the second switch and the third switch.

[0088] For example, when performing impedance calibration, the processor can control the second switch S2 and the third switch S3 according to the switch combination state described in FIG4 , thereby solving the three parameters a, b, and c through the three impedance states and the three calculation equations constructed by the calculation formula (1), thereby achieving impedance calibration of the input circuit.

[0089] S103: Close the first switch.

[0090] After the impedance of the input circuit connected to the input port RFin is calibrated, the first switch S1 can be closed through the RF IC, and the switch in the tuning circuit 400 can be controlled according to the reflection coefficient determined by the above-mentioned forward transmission signal and reverse transmission signal, thereby performing impedance tuning on the load (including but not limited to the antenna).

[0091] S104: Tuning a load connected to the output port through a plurality of switch combination states of the second switch and the third switch.

[0092] The switch combination state of the second switch S2 and the third switch S3 can also be controlled by a control signal sent by a processor in the RF IC, or by a control signal sent by a processor connected to the RF IC. In addition, when tuning, the processor can determine the switch combination state of the second switch S2 and the third switch S3 by looking up a table. For example, the operator can determine the switch combination state of the second switch S2 and the third switch S3 based on the reflection coefficient Γ at the measuring end. MRx The lookup table is constructed based on the tuning relationship between the switch combination state of the second switch S2 and the third switch S3. Then, the processor uses the reflection coefficient Γ detected in real time to calculate the reflection coefficient Γ. MRx The switch combination state of the second switch S2 and the third switch S3 is determined from the lookup table, and the switch states of the second switch S2 and the third switch S3 are controlled according to the switch combination state, thereby achieving load impedance tuning.

[0093] In the above implementation process, each switch or adjustable capacitor in Figures 5 to 9 can also be controlled by the tuning method set in the lookup table, which will not be described in detail in the embodiments of the present application. At the same time, S101 and S102 are optional steps and are only performed when the impedance calibration of the input circuit connected to the input port RFin is required. In addition, in addition to being used for impedance tuning of the load, the above tuning circuit 400 can also replace the specific absorption rate (SAR) sensor for SAR testing. Because there is a certain mapping relationship between the impedance of the antenna and the distance of the human body close to the antenna, in principle, the impedance change can be used to detect whether a human body is approaching, thereby replacing the existing SAR sensor function.

[0094] In some embodiments, as shown in FIG11 , the present invention further provides a tuning chip 1100, comprising a substrate 1110 and the tuning circuit 400 disposed on the substrate 1110. The substrate 1110 can be any conventional substrate used in chip manufacturing, such as a printed circuit board (PCB) or a silicon substrate. The tuning circuit 400 can utilize any of the aforementioned embodiments, and the present invention does not impose any specific limitations thereon.

[0095] In some embodiments, as shown in FIG12 , an embodiment of the present application further provides an electronic device 1200. The electronic device 1200 includes a radio frequency integrated circuit 1210, a bidirectional coupler 1220, an antenna 1230, and a tuning chip 1100. The radio frequency integrated circuit 1210 includes an output terminal Tx and a measurement terminal MRx. The input terminal a of the bidirectional coupler 1220 is coupled to the output terminal Tx of the radio frequency integrated circuit 1210 through a power amplifier 1240. The input port RFin of the tuning chip 1100 is coupled to the output terminal b of the bidirectional coupler 1220. The output port RFout of the tuning chip 1100 is coupled to the antenna 1230. The coupling ends of the bidirectional coupler 1220 (including the forward coupling end Fwr and the reverse coupling end Rev) are coupled to the measurement terminal MRx of the radio frequency integrated circuit 1210 in sequence through a selection switch SW and an attenuator 1250. Among them, the above-mentioned electronic device 1200 can be a Bluetooth module, a cellular communication module, a mobile terminal device (such as a mobile phone, a computer, a smart bracelet, a smart watch), a local area network device, a server, or other devices that require antenna tuning. The embodiment of the present application does not impose specific restrictions on this.

[0096] Furthermore, in the above implementation process, the chip or electronic device in the above example may also include other types of devices, and the embodiments of the present application do not impose specific limitations on this.

[0097] Those skilled in the art will appreciate that the functions of the circuits described in the various examples of the embodiments disclosed herein can be implemented using electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0098] In the several embodiments provided in this application, it should be understood that the disclosed circuits and electronic devices can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of modules is only a logical function division. In actual implementation, there may be other division methods, such as multiple modules or components can be combined or integrated into another device, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be through some interface, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0099] In addition, the chips in each embodiment of the present application may be integrated into one device, or each module may exist physically separately, or two or more modules may be integrated into one device.

[0100] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art 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. A tuning circuit, characterized in that: include: An input port, an output port, a first switch, a second switch, and an impedance adjustment circuit; A first end of the first switch is coupled to the input port; a second end of the first switch is coupled to the output port; A first end of the second switch is coupled to the input port; a second end of the second switch is coupled to a first end of the impedance adjustment circuit; The second end of the impedance adjustment circuit is grounded, and the impedance adjustment circuit includes a third switch and a first impedance element connected in parallel between the first end and the second end of the impedance adjustment circuit.

2. The tuning circuit according to claim 1, characterized in that: The impedance adjustment circuit further includes a fourth switch and a second impedance element connected in parallel; after the third switch and the first impedance element are connected in parallel, they are grounded through the fourth switch and the second impedance element connected in parallel.

3. The tuning circuit according to claim 1, characterized in that: The impedance adjustment circuit further includes a fifth switch, a sixth switch, a third impedance element and a fourth impedance element; wherein, After the third switch and the first impedance element are connected in parallel, they are grounded through the fifth switch and the third impedance element connected in series; meanwhile, after the third switch and the first impedance element are connected in parallel, they are also grounded through the sixth switch and the fourth impedance element connected in series.

4. The tuning circuit according to any one of claims 1 to 3, characterized in that: Also includes: A first adjustable capacitor; wherein a first end of the first adjustable capacitor is coupled to a second end of the first switch; and a second end of the first adjustable capacitor is coupled to the output port.

5. The tuning circuit according to claim 4, characterized in that: Also includes: A second adjustable capacitor is connected in parallel with the first adjustable capacitor.

6. The tuning circuit according to any one of claims 1 to 5, characterized in that: Also includes: a seventh switch and a first connection port; A first end of the seventh switch is coupled to the input port; a second end of the seventh switch is coupled to the first connection port; The first connection port is used to connect a fifth impedance element.

7. The tuning circuit according to claim 6, characterized in that: Also includes: an eighth switch and a second connection port; a first end of the eighth switch is coupled to the input port; a second end of the eighth switch is coupled to the second connection port; The second connection port is used to connect a sixth impedance element.

8. The tuning circuit according to any one of claims 1 to 7, characterized in that: Also includes: a ninth switch and a third connection port; a first end of the ninth switch is coupled to the output port; a second end of the ninth switch is coupled to the third connection port; The third connection port is used to connect the seventh impedance element.

9. The tuning circuit according to claim 8, characterized in that: Also includes: a tenth switch and a fourth connection port; a first end of the tenth switch is coupled to the output port; a second end of the tenth switch is coupled to the fourth connection port; The fourth connection port is used to connect to the eighth impedance element.

10. The tuning circuit according to any one of claims 2 to 9, characterized in that: Also includes: an eleventh switch and a twelfth switch; the first end of the eleventh switch is coupled to the first end of the impedance adjustment circuit; the second end of the eleventh switch and the first end of the twelfth switch are both coupled to the second end of the first adjustable capacitor; the second end of the twelfth switch is coupled to the output port.

11. The tuning circuit according to claim 10, characterized in that: The eleventh switch and the second switch are the same single-pole multi-throw switch; wherein the first end of the eleventh switch and the second end of the second switch are common ends of the single-pole multi-throw switch; the second end of the eleventh switch is a first contact of the single-pole multi-throw switch; and the first end of the second switch is a second contact of the single-pole multi-throw switch.

12. A tuning method, characterized in that: The invention is applied to a tuning circuit, the tuning circuit comprises an input port, an output port, a first switch, a second switch and an impedance adjustment circuit; the first end of the first switch is coupled to the input port; the second end of the first switch is coupled to the output port; the first end of the second switch is coupled to the input port; the second end of the second switch is coupled to the first end of the impedance adjustment circuit; the second end of the impedance adjustment circuit is grounded, and the impedance adjustment circuit comprises a third switch and a first impedance element connected in parallel between the first end and the second end of the impedance adjustment circuit; the method comprises: closing the first switch; A load connected to the output port is tuned by a plurality of switch combination states of the second switch and the third switch.

13. The method according to claim 12, characterized in that The method further comprises: Disconnecting the first switch; The impedance of the input circuit connected to the input port is calibrated through a plurality of switch combination states of the second switch and the third switch.

14. A tuning chip, characterized in that: The invention comprises: a lining plate, and a tuning circuit as claimed in any one of claims 1 to 11 arranged on the lining plate.

15. An electronic device, characterized in that: It includes a radio frequency integrated circuit, a bidirectional coupler, an antenna and the tuning chip as described in claim 14; the radio frequency integrated circuit includes an output end and a measuring end; the input end of the bidirectional coupler is coupled to the output end of the radio frequency integrated circuit; the input port of the tuning chip is coupled to the output end of the bidirectional coupler; the output port of the tuning chip is coupled to the antenna; the coupling end of the bidirectional coupler is coupled to the measuring end of the radio frequency integrated circuit.

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