A radio frequency power amplification circuit and a radio frequency choke circuit

Abstract

The application relates to a radio frequency power amplification circuit and a radio frequency choke circuit, and relates to the technical field of radio frequency power amplifiers. The radio frequency choke circuit comprises a first inductive circuit and a second inductive circuit in parallel; wherein the first inductive circuit comprises a first inductor L1 and a second inductor L2 in series, and the second inductive circuit comprises a third inductor L3. Compared with the prior art, with the increase of the signal frequency, an equivalent capacitor of the first inductive circuit resonates with the third inductor L3 in parallel. Since the impedance amplitude of the equivalent circuit at the resonance frequency point and in the nearby frequency band is relatively large, a high impedance amplitude can be provided in a relatively large bandwidth range to restrain the radio frequency signal from entering the VDD power supply, and the bandwidth range of the choke effect is significantly improved.

Description

Technical Field

[0001] This invention relates to the field of radio frequency power amplifier technology, specifically to a radio frequency power amplifier circuit and a radio frequency choke circuit. Background Technology

[0002] The radio frequency (RF) power amplifier circuit includes an RF power amplifier (PA) and its matching circuit. The matching circuit includes an RF choke circuit. The function of the RF choke circuit is to provide a DC connection, connecting the drain power supply VDD of the RF power amplifier to the drain signal output terminal to supply power to the drain of the RF power transistor. At the same time, it provides a large impedance amplitude within the operating frequency band of the RF power amplifier to prevent the RF signal on the drain of the RF power transistor from entering the VDD power supply, thereby preventing the RF signal on the drain of the power transistor from interfering with the VDD power supply.

[0003] However, traditional RF choke circuits have relatively small bandwidth, making it difficult to achieve a choke effect over a large bandwidth range. Summary of the Invention

[0004] The technical problem to be solved by this application is to provide an RF power amplifier circuit and an RF choke circuit, which have the feature of improving the bandwidth range of the choke effect.

[0005] In one aspect, one embodiment provides a radio frequency (RF) power amplifier circuit, including an RF power amplifier T1 and its matching circuit. The matching circuit includes an input matching circuit IMN, an output matching circuit OMN, a gate bias circuit, and an RF choke circuit. The gate signal input terminal of the RF power amplifier T1 is connected to the amplified signal input terminal IN via the input matching circuit IMN and to the gate power supply VGG via the gate bias circuit. The drain signal output terminal of the RF power amplifier T1 is connected to the amplified signal output terminal OUT via the output matching circuit OMN and to the drain power supply VDD via the RF choke circuit. The radio frequency choke circuit includes a first inductor circuit and a second inductor circuit connected in parallel; the first inductor circuit includes a first inductor L1 and a second inductor L2 connected in series, and the second inductor circuit includes a third inductor L3.

[0006] In one embodiment, the first inductor L1 and the second inductor L2 are the same discrete inductors.

[0007] In one embodiment, the self-resonant frequencies of the first inductor L1 and the second inductor L2 are taken from the center frequency of the operating frequency of the radio frequency power amplifier T1.

[0008] In one embodiment, the third inductor L3 is an inductor with a parasitic capacitance of less than 0.05pF.

[0009] In a second aspect, one embodiment provides a radio frequency choke circuit, including a first inductor circuit and a second inductor circuit connected in parallel; the first inductor circuit includes a first inductor L1 and a second inductor L2 connected in series, and the second inductor circuit includes a third inductor L3.

[0010] In one embodiment, the first inductor L1 and the second inductor L2 are the same discrete inductors.

[0011] In one embodiment, the self-resonant frequencies of the first inductor L1 and the second inductor L2 are taken from the center frequency of the operating frequency of the applied circuit.

[0012] In one embodiment, the third inductor L3 is an inductor with a parasitic capacitance of less than 0.05pF.

[0013] The beneficial effects of this invention are: Since the impedance of the equivalent circuits of the first inductor L1 and the second inductor L2, which are connected in series, becomes capacitive after the signal frequency exceeds the self-resonant frequency, the series circuit of the first inductor L1 and the second inductor L2 can be equivalent to a capacitor. As the signal frequency increases, this equivalent capacitor resonates in parallel with the third inductor L3. Because the impedance amplitude of the equivalent circuit at the resonant frequency and in the vicinity is relatively large, a high impedance amplitude can be provided over a large bandwidth to suppress the RF signal from entering the VDD power supply, significantly improving the choking bandwidth. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of a commonly used traditional radio frequency choke circuit structure; Figure 2 yes Figure 1 A schematic diagram of the equivalent circuit structure of the circuit shown. Figure 3 This is a schematic diagram of the radio frequency choke circuit structure according to an embodiment of this application; Figure 4 yes Figure 3 The equivalent circuit structure diagram of the radio frequency choke circuit shown is shown. Figure 5 yes Figure 3 The diagram shows the equivalent circuit structure of the RF choke circuit after the operating signal frequency exceeds the self-resonant frequency. Figure 6 This is a schematic diagram of a radio frequency power amplifier circuit according to an embodiment of this application; Figure 7 yes Figure 3 The RF choke circuit shown is Figure 1The diagram shows the simulation effect of the impedance amplitude changing as the operating frequency increases when the RF choke circuit is applied in an RF power amplifier circuit.

[0015] In the diagram: 01, the first inductor circuit; 02, the second inductor circuit. Detailed Implementation

[0016] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings. Similar elements in different embodiments are referred to by associated similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of this application. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, certain operations related to this application are not shown or described in the specification. This is to avoid obscuring the core parts of this application with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0017] Furthermore, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments. At the same time, the steps or actions in the method description can be rearranged or adjusted in a manner obvious to those skilled in the art. Therefore, the various orders in the specification and drawings are only for the clear description of a particular embodiment and do not imply a necessary order, unless otherwise stated that a particular order must be followed.

[0018] The serial numbers assigned to components in this document, such as "first" and "second," are used only to distinguish the objects being described and have no sequential or technical meaning. Unless otherwise specified, the terms "connection" and "linkage" used in this application include both direct and indirect connections (linkages).

[0019] To facilitate the explanation of the inventive concept of this application, the radio frequency choke technology will be briefly described below.

[0020] Please refer to Figure 1 In a traditional and commonly used RF choke circuit, only a single discrete inductor L4 is used. In an RF power amplifier circuit, one end of the discrete inductor L4 is connected to the drain of the RF power amplifier (PA), and the other end is connected to the drain power supply of the RF power amplifier. This discrete inductor L4 provides a large impedance amplitude within the operating frequency band of the RF power amplifier, preventing the RF signal on the drain of the RF power transistor from entering the VDD power supply, thereby preventing the RF signal on the drain of the power transistor from interfering with the VDD power supply.

[0021] However, the applicant found during the research that, please refer to Figure 2 ,for Figure 1 The equivalent circuit of the RF choke circuit shown is illustrated. This equivalent circuit includes a fifth inductor L5 and a fifth capacitor C5 connected in parallel. The fifth capacitor C5 is a parasitic capacitance caused by the coupling between the inductors. Due to the presence of the parasitic capacitance C5, and its parallel connection with L5, the equivalent circuit will experience parallel self-resonance at a certain frequency. Although the impedance amplitude at the self-resonance point is particularly large, when the frequency exceeds this self-resonance frequency, the equivalent circuit becomes capacitive, and the impedance amplitude decreases with increasing frequency. This results in the poor bandwidth characteristics of conventionally used RF choke circuits; that is, conventionally used RF choke circuits cannot provide a high impedance amplitude over a large bandwidth to prevent the RF signal at the drain of the RF power transistor from entering the VDD power supply.

[0022] Therefore, this application provides an RF power amplifier circuit and an RF choke circuit. The RF choke circuit includes a first inductor circuit and a second inductor circuit connected in parallel. The first inductor circuit includes a first inductor L1 and a second inductor L2 connected in series, and the second inductor circuit includes a third inductor L3. Since the impedance of the equivalent circuits of the first inductor L1 and the second inductor L2 becomes capacitive after the signal frequency exceeds the self-resonant frequency, the series circuit of the first inductor L1 and the second inductor L2 can be equivalent to a capacitor after the signal frequency exceeds the self-resonant frequency. As the signal frequency increases, this equivalent capacitor resonates in parallel with the third inductor L3. Since the impedance amplitude of the equivalent circuit at the resonant frequency and in the nearby frequency band is relatively large, a high impedance amplitude can be provided over a large bandwidth to choke the RF signal into the VDD power supply, significantly improving the choke effect bandwidth.

[0023] The following section will first explain the radio frequency choke circuit.

[0024] Please refer to Figure 3 One embodiment of this application provides a radio frequency choke circuit, including a first inductor circuit 01 and a second inductor circuit 02 connected in parallel. The first inductor circuit 01 includes a first inductor L1 and a second inductor L2 connected in series, and the second inductor circuit 02 includes a third inductor L3.

[0025] Please refer to Figure 4 ,for Figure 3The equivalent circuit of the RF choke circuit shown is illustrated, where the first inductor L1 can be equivalent to a parallel connection of inductor L11 and capacitor C11, and the second inductor L2 can be equivalent to a parallel connection of inductor L2 and capacitor C22. Capacitor C11 is the parasitic capacitance caused by the direct coupling of the coils of the first inductor L1, and capacitor C22 is the parasitic capacitance caused by the direct coupling of the coils of the second inductor L2. The impedance of the equivalent circuits of the first inductor L1 and the second inductor L2 becomes capacitive after the operating RF signal frequency exceeds the self-resonant frequency. Because it is capacitive, after the signal frequency exceeds the self-resonant frequency of the first inductor L1 and the second inductor L2, the series circuit of the first inductor L1 and the second inductor L2 can be equivalent to a single capacitor C3.

[0026] Please refer to Figure 5 ,for Figure 3 In the RF choke circuit shown, the equivalent circuit after the operating signal frequency exceeds the self-resonant frequency includes a third inductor L3 and a capacitor C3 connected in parallel. As the operating signal frequency increases, the third inductor L3 and the capacitor C3 resonate in parallel. Since the impedance amplitude of the equivalent circuit at the resonant frequency and in the vicinity of the frequency band is relatively large, it can provide a high impedance amplitude over a large bandwidth to choke the RF signal into the power supply, which significantly improves the bandwidth of the choke effect.

[0027] In one embodiment, to achieve better RF choke performance, the first inductor L1 and the second inductor L2 are discrete inductors with the same inductance value.

[0028] In one embodiment, to achieve better operating conditions, the self-resonant frequencies of the first inductor L1 and the second inductor L2 are adopted from the center frequency of the operating frequency of the applied circuit (the circuit in which it is located).

[0029] In one embodiment, to achieve better parallel resonance, the third inductor L3 is an inductor with a large inductance value and low parasitic capacitance. In another embodiment, the third inductor L3 is an inductor with a parasitic capacitance value of less than 0.05pF.

[0030] One embodiment of this application provides a radio frequency power amplifier circuit; please refer to [reference needed]. Figure 6 The RF power amplifier circuit includes an RF power amplifier T1 and its matching circuit. The matching circuit includes an input matching circuit IMN, an output matching circuit OMN, a gate bias circuit, and an RF choke circuit. The gate signal input terminal of the RF power amplifier T1 is connected to the amplified signal input terminal IN through the input matching circuit IMN, and to the gate power supply VGG through the gate bias circuit. The drain signal output terminal of the RF power amplifier T1 is connected to the amplified signal output terminal OUT through the output matching circuit OMN, and to the drain power supply VDD through the RF choke circuit.

[0031] in, Figure 6 The RF choke circuit in the RF power amplifier circuit shown can be any of the RF choke circuits described in the above embodiments.

[0032] Those skilled in the art will understand that Figure 6 The hardware structure of the RF power amplifier circuit shown does not constitute a limitation on the RF power amplifier circuit, and may include more circuit structures than shown, or combine certain circuit structures.

[0033] In one embodiment, the self-resonant frequencies of the first inductor L1 and the second inductor L2 in the RF choke circuit are taken from the center frequency of the RF power amplifier. Since the impedance amplitude of the equivalent circuit at the resonant frequency and in the vicinity is relatively large, a high impedance amplitude can be provided over a large bandwidth to prevent the RF signal in the RF amplifier circuit from entering the VDD power supply.

[0034] Please refer to Figure 7 ,for Figure 3 The RF choke circuit shown (the solution in this application) and Figure 1 The RF choke circuit shown (conventional solution) is used in RF power amplifier circuits. As the operating frequency increases, the impedance amplitude changes. It can be seen that the RF choke circuit of this application maintains a high impedance amplitude throughout the 800MHz~1800MHz frequency band, with a bandwidth of 1000MHz. In contrast, the conventional solution only maintains a high impedance amplitude within the 1200MHz~1400MHz range, with a bandwidth of only 200MHz. Therefore, the performance of the RF choke circuit of this application is significantly superior to the conventional solution, improving the bandwidth range of the choke effect.

[0035] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. A radio frequency power amplifier circuit, characterized in that, The system includes an RF power amplifier T1 and its matching circuit. The matching circuit includes an input matching circuit IMN, an output matching circuit OMN, a gate bias circuit, and an RF choke circuit. The gate signal input terminal of the RF power amplifier T1 is connected to the amplified signal input terminal IN through the input matching circuit IMN and to the gate power supply VGG through the gate bias circuit. The drain signal output terminal of the RF power amplifier T1 is connected to the amplified signal output terminal OUT through the output matching circuit OMN and to the drain power supply VDD through the RF choke circuit. The radio frequency choke circuit includes a first inductor circuit and a second inductor circuit connected in parallel; the first inductor circuit includes a first inductor L1 and a second inductor L2 connected in series, and the second inductor circuit includes a third inductor L3, wherein the third inductor L3 is an inductor with low parasitic capacitance. Wherein, after the signal frequency exceeds the self-resonant frequency of the first inductor L1 and the second inductor L2, the first inductor circuit is equivalent to a capacitor. This equivalent capacitor and the third inductor L3 form a parallel resonant circuit to provide a high impedance amplitude to suppress the radio frequency signal from entering the drain power supply VDD and improve the range of the choking bandwidth.

2. The radio frequency power amplifier circuit as described in claim 1, characterized in that, The first inductor L1 and the second inductor L2 are the same discrete inductors.

3. The radio frequency power amplifier circuit as described in claim 1, characterized in that, The self-resonant frequencies of the first inductor L1 and the second inductor L2 are taken from the center frequency of the operating frequency of the RF power amplifier T1.

4. The radio frequency power amplifier circuit as described in claim 1, characterized in that, The third inductor L3 is an inductor with a parasitic capacitance of less than 0.05pF.

5. A radio frequency choke circuit, characterized in that, An application is made to an RF power amplifier circuit including an RF power amplifier T1, wherein the RF choke circuit includes a first inductor circuit and a second inductor circuit connected in parallel; the first inductor circuit includes a first inductor L1 and a second inductor L2 connected in series, and the second inductor circuit includes a third inductor L3, wherein the third inductor L3 is an inductor with low parasitic capacitance. The input terminal of the RF choke circuit is connected to the drain signal output terminal of the RF power amplifier T1, and the output terminal is connected to the drain power supply VDD that provides the operating voltage to the drain of the RF power amplifier T1. When the signal frequency exceeds the self-resonant frequency of the first inductor L1 and the second inductor L2, the first inductor circuit is equivalent to a capacitor. This equivalent capacitor and the third inductor L3 form a parallel resonant circuit to provide a high impedance amplitude to choke the RF signal into the drain power supply VDD and improve the choke bandwidth range.

6. The radio frequency choke circuit as described in claim 5, characterized in that, The first inductor L1 and the second inductor L2 are the same discrete inductors.

7. The radio frequency choke circuit as described in claim 5, characterized in that, The self-resonant frequencies of the first inductor L1 and the second inductor L2 are taken from the center frequency of the operating frequency of the applied circuit.

8. The radio frequency choke circuit as described in claim 5, characterized in that, The third inductor L3 is an inductor with a parasitic capacitance of less than 0.05pF.

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