Tunable inductor and impedance matching circuit

Abstract

The utility model relates to a tunable inductor and an impedance matching circuit, the tunable inductor comprises a first inductor, a second inductor and a control switch network which are mutually coupled, the first end of the first inductor is connected with the first end of the second inductor, the second end of the first inductor is grounded, the second end of the second inductor is grounded, and the impedance matching circuit is connected with the control switch network. The first end of the control switch network is connected with the first end of the second inductor, and the second end of the control switch network is connected with the second end of the second inductor; the control switch network is used for adjusting the inductance value of the second inductor. According to the utility model, the inductance value of the inductor is adjusted through the control switch network with a non-switch structure, so that the influence of switch insertion loss on the inductor is avoided.

Description

Technical Field

[0001] The utility model is applicable to the technical field of wireless communication radio frequency, and in particular relates to a tunable inductor and impedance matching circuit. Background Art

[0002] With the continuous advancement of communication technology, communication systems are placing increasingly stringent demands on power amplifiers. Currently, 5G communication systems widely utilize broadband modulation technologies such as carrier aggregation. This technology aggregates subchannels to form a broadband modulated signal, enabling high-speed data transmission. Driven by this demand, the bandwidth performance of power amplifiers has become increasingly important. How to simultaneously meet the requirements of high efficiency and high linearity across a wider frequency range has become a hot topic in current research.

[0003] Traditional uplink broadband communications use multiple power amplifiers optimized for each frequency band, and switches are used to switch between different frequency bands. In order to make a single-chip power amplifier cover a wider frequency band, the load impedance should be kept near the optimal value throughout the entire operating frequency band. Related technologies use the output matching network of tunable matching elements to increase the impedance tuning range, thereby effectively improving the power amplifier bandwidth. A more common tunable inductor solution is Figure 1 As shown, Figure 1 The tunable inductor in the circuit sets several parallel inductors to appropriate inductance values ​​and directly controls the conduction or opening of the parallel inductors through switches, thereby improving the impedance tuning range of the output matching network. However, this solution increases the complexity and cost of the system and requires a large area. In addition, the presence of the switch brings additional insertion loss to the entire system, such as Figure 1 In the technical solution shown, the switch insertion loss will cause the inductor Q value to decrease, thereby reducing the Q value of the entire matching network, which may lead to deterioration of the power amplifier performance.

[0004] Therefore, it is necessary to propose a new tunable inductor to solve the above technical problems. Utility Model Content

[0005] The utility model provides a tunable inductor and an impedance matching circuit, aiming to solve the problem of extra insertion loss in the existing tunable inductor based on a switch structure.

[0006] To solve the above technical problems, in a first aspect, the present invention provides a tunable inductor, comprising a first inductor and a second inductor coupled to each other, and a control switch network, wherein a first end of the first inductor is connected to a first end of the second inductor, a second end of the first inductor is grounded, and a second end of the second inductor is grounded, a first end of the control switch network is connected to a first end of the second inductor, and a second end of the control switch network is connected to a second end of the second inductor;

[0007] The control switch network is used to adjust the inductance of the second inductor.

[0008] Furthermore, the control switch network includes a diode, a third inductor, and a first capacitor, wherein the positive terminal of the diode serves as the first terminal of the control switch network and is connected to the first terminal of the second inductor, and the negative terminal of the diode serves as the second terminal of the control switch network and is connected to the second terminal of the second inductor;

[0009] A first end of the third inductor is connected to the cathode end of the diode, and a second end of the third inductor is connected to a DC voltage;

[0010] A first end of the first capacitor is connected to the second end of the third inductor, and a second end of the first capacitor is grounded.

[0011] Furthermore, the third inductor is a choke inductor.

[0012] Furthermore, the first capacitor is a decoupling capacitor.

[0013] In a second aspect, the present invention further provides an impedance matching circuit, which includes the tunable inductor provided by the present invention as described above.

[0014] The beneficial effect achieved by the present invention is that a tunable inductor based on a diode structure is proposed. The circuit structure adjusts the inductance value of the inductor through a control switch network of a non-switching structure, thereby avoiding the influence of switch insertion loss on the inductor. In the application of a power amplifier, the output impedance of the power amplifier using the tunable inductor can maintain an optimal state within a wider frequency band, thereby achieving the effect of improving the broadband of the power amplifier. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the circuit structure of a tunable inductor in the prior art;

[0016] Figure 2 This is a schematic diagram of the circuit structure of the tunable inductor provided by an embodiment of the utility model;

[0017] Figure 3 It is a circuit structure diagram of the impedance matching circuit provided by an embodiment of the utility model. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0019] Please refer to Figure 2 , Figure 2 : This is a schematic diagram of the circuit structure of a tunable inductor provided by an embodiment of the present invention. The tunable inductor 100 includes a first inductor L1 and a second inductor L2 coupled to each other, and a control switch network 101. The first end of the first inductor L1 is connected to the first end of the second inductor L2, the second end of the first inductor L1 is grounded, and the second end of the second inductor L2 is grounded. The first end of the control switch network 101 is connected to the first end of the second inductor L2, and the second end of the control switch network 101 is connected to the second end of the second inductor L2.

[0020] The control switch network 101 is used to adjust the inductance of the second inductor L2.

[0021] Specifically, the control switch network 101 includes a diode D1, a third inductor L3, and a first capacitor C1. The positive terminal of the diode D1 serves as the first terminal of the control switch network 101 and is connected to the first terminal of the second inductor L2. The negative terminal of the diode D1 serves as the second terminal of the control switch network 101 and is connected to the second terminal of the second inductor L2.

[0022] A first end of the third inductor L3 is connected to the cathode end of the diode D1, and a second end of the third inductor L3 is connected to the DC voltage Vsw; the third inductor L3 is a choke inductor (RF Choke);

[0023] A first end of the first capacitor C1 is connected to the second end of the third inductor L3 , and a second end of the first capacitor C1 is grounded. The first capacitor C1 is a decoupling capacitor (Bypass Capacitor).

[0024] Based on the circuit structure of the tunable inductor 100, during implementation, the voltage across diode D1 is controlled by adjusting the DC voltage Vsw. When DC voltage Vsw is greater than the turn-on voltage of diode D1, diode D1 conducts; when DC voltage Vsw is less than the turn-on voltage of diode D1, diode D1 turns off. By switching diode D1 between on and off states, the inductance of second inductor L2 is controlled, achieving adjustable inductance.

[0025] The present invention also provides an impedance matching circuit 200, which includes the tunable inductor 100 described in the above embodiment. Figure 3 , Figure 3 : is a schematic diagram of the circuit structure of the impedance matching circuit provided by the embodiment of the utility model, Figure 3The impedance matching circuit 200 shown can be used in a matching network of a power amplifier to achieve impedance tuning of the matching network. When in use, the tunable inductor 100 is connected in parallel with the fourth inductor L4 and in series with the fifth inductor L5 (i.e., the fourth inductor L4 is used as a coupling object of the tunable inductor 100). This design enables the output impedance of the power amplifier to maintain an optimal state within a wider frequency band, thereby improving the bandwidth of the power amplifier.

[0026] The beneficial effect achieved by the present invention is that a tunable inductor based on a diode structure is proposed. The circuit structure adjusts the inductance value of the inductor through a control switch network of a non-switching structure, thereby avoiding the influence of switch insertion loss on the inductor. In the application of a power amplifier, the output impedance of the power amplifier using the tunable inductor can maintain an optimal state within a wider frequency band, thereby achieving the effect of improving the broadband of the power amplifier.

[0027] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0028] The embodiments of the present invention are described above in conjunction with the accompanying drawings. What is disclosed is only a preferred embodiment of the present invention. However, the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms and equivalent changes without departing from the scope of protection of the purpose of the present invention and the claims, which are all within the protection of the present invention.

Claims

1. A tunable inductor, characterized in that: The tunable inductor includes a first inductor and a second inductor coupled to each other, and a control switch network, wherein a first end of the first inductor is connected to a first end of the second inductor, a second end of the first inductor is grounded, a second end of the second inductor is grounded, a first end of the control switch network is connected to a first end of the second inductor, and a second end of the control switch network is connected to a second end of the second inductor; The control switch network is used to adjust the inductance of the second inductor.

2. The tunable inductor according to claim 1, characterized in that: The control switch network includes a diode, a third inductor, and a first capacitor, wherein the positive terminal of the diode serves as the first terminal of the control switch network and is connected to the first terminal of the second inductor, and the negative terminal of the diode serves as the second terminal of the control switch network and is connected to the second terminal of the second inductor; A first end of the third inductor is connected to the cathode end of the diode, and a second end of the third inductor is connected to a DC voltage; A first end of the first capacitor is connected to the second end of the third inductor, and a second end of the first capacitor is grounded.

3. The tunable inductor according to claim 2, characterized in that: The third inductor is a choke inductor.

4. The tunable inductor according to claim 2, characterized in that: The first capacitor is a decoupling capacitor.

5. An impedance matching circuit, characterized in that: The impedance matching circuit includes the tunable inductor according to any one of claims 1 to 4.

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