Harmonic suppression circuit, transmitter

Abstract

The present invention provides a harmonic suppression circuit and a transmitter. The harmonic suppression circuit is applied to the transmitter and includes: a current source, a first inductor, a second inductor, a capacitor, a power amplifier, a balun, and an antenna. The positive pole of the current source is electrically connected to the first end of the first inductor, and the second end of the first inductor is electrically connected to one end of the capacitor and the first end of the second inductor. The negative pole of the current source is grounded, the negative pole of the capacitor is grounded, and the second inductor adjusts the common-mode impedance on the current source side to suppress the harmonic components generated by the power amplifier. The second end of the second inductor is electrically connected to the balun, and the position where the balun is electrically connected to the second inductor is at the central position between the first end and the second end of the balun. The harmonic suppression circuit provided by the present invention can produce a good suppression effect on the harmonic components of the power amplifier on the premise of ensuring the stability of the current signal.

Description

Technical Field

[0001] The present invention relates to the technical field of radio frequency transmitter design for semiconductor integrated circuits, and particularly relates to a harmonic suppression circuit and a transmitter. Background Art

[0002] Currently, the end structure of the transmitter is as Figure 1 shown, including: antenna T, balun BL, power amplifier PA, inductor L BW , current source V. In order to provide a stable current signal for the power amplifier PA in the transmitter, a large capacitor C is usually connected in parallel to the current source for outputting this current signal supply . However, in the transmitter, the current source with the large capacitor in parallel is close to an ideal AC ground, weakening the suppression effect on the harmonic components generated by the power amplifier.

[0003] The harmonic components will affect the performance of the power amplifier such as efficiency, output power, linearity, etc., thus increasing the power consumption of the power amplifier.

[0004] Therefore, the present invention proposes a harmonic suppression circuit and a transmitter to achieve a good suppression effect on the harmonic components generated by the power amplifier on the premise of ensuring the stability of the current signal. Summary of the Invention

[0005] The present invention provides a harmonic suppression circuit and a transmitter to solve the technical problem in the prior art that connecting a large capacitor in parallel to the current source for outputting this current signal will weaken the suppression effect on the harmonic components generated by the power amplifier.

[0006] In a first aspect, the present invention provides a harmonic suppression circuit applied to a transmitter, including: a current source, a first inductor, a second inductor, a capacitor, a power amplifier, a balun, and an antenna; the positive pole of the current source is electrically connected to the first end of the first inductor, the second end of the first inductor is electrically connected to one end of the capacitor and the first end of the second inductor; the negative pole of the current source is grounded, the negative pole of the capacitor is grounded, and the second inductor adjusts the common-mode impedance on the current source side to suppress the harmonic components generated by the power amplifier; the second end of the second inductor is electrically connected to the balun, and the position where the balun is electrically connected to the second inductor is at the central position between the first end and the second end of the balun; the first end of the balun is electrically connected to the first output end of the power amplifier, the second end of the balun is electrically connected to the second output end of the power amplifier; the third end of the balun is electrically connected to the antenna, and the fourth end of the balun is grounded.

[0007] The beneficial effects are as follows: For the harmonic suppression circuit provided by the present invention, by connecting an inductor in parallel on the current source side, it can produce a good suppression effect on the harmonic components of the power amplifier while ensuring the stability of the current signal.

[0008] Optionally, the power amplifier includes: a first N-type transistor, a second N-type transistor, a third N-type transistor, and a fourth N-type transistor; the source electrode of the first N-type transistor is connected to the source electrode of the second N-type transistor, the source electrode of the first N-type transistor is grounded, and the drain electrode of the first N-type transistor is connected to the source electrode of the third N-type transistor; the drain electrode of the second N-type transistor is connected to the source electrode of the fourth N-type transistor; the gate electrode of the third N-type transistor is connected to the gate electrode of the fourth N-type transistor, and the drain electrode of the third N-type transistor is connected to the first end of the balun; the drain electrode of the fourth N-type transistor is connected to the second end of the balun. The beneficial effects are as follows: The harmonic suppression circuit provided by the present invention has a good suppression effect on the harmonic components generated by the power amplifier with this structure.

[0009] In a second aspect, the present invention provides a transmitter, including the harmonic suppression circuit according to any one of the first aspects.

[0010] The beneficial effects are as follows: The transmitter provided by the present invention can produce a good suppression effect on the harmonic components generated by the power amplifier while ensuring the stability of the power supply current source of the power amplifier. Description of the Drawings

[0011] Figure 1 It is a schematic structural diagram of a transmitter end circuit in the prior art;

[0012] Figure 2 It is a schematic diagram of a structural embodiment of a harmonic suppression circuit provided by the present invention;

[0013] Figure 3 It is a schematic diagram of a structural embodiment of a power amplifier provided by the present invention. Detailed Embodiments

[0014] The following describes the technical solutions in the embodiments of the present application in conjunction with the accompanying drawings in the embodiments of the present application. Among them, in the description of the embodiments of the present application, the terms used in the following embodiments are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification and appended claims of the present application, the singular forms "a", "the", "above-mentioned", "the" and "this" are also intended to include forms such as "one or more", unless the context clearly indicates otherwise. It should also be understood that in the following embodiments of the present application, "at least one" and "one or more" mean one or more than two (including two). The term "and / or" is used to describe the association relationship of associated objects and indicates that three relationships can exist; for example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone, where A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after.

[0015] References in this specification to "one embodiment" or "some embodiments" or the like mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the present application. Thus, the phrases "in one embodiment", "in some embodiments", "in other some embodiments", "in still other embodiments" and the like that appear in different places in this specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in another way. The terms "comprising", "including", "having" and their variants all mean "including but not limited to", unless otherwise specifically emphasized in another way. The term "connection" includes direct connection and indirect connection, unless otherwise stated. "First" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features.

[0016] In the embodiments of the present application, words such as "exemplarily" or "for example" are used to give examples, illustrations or explanations. Any embodiment or design described as "exemplarily" or "for example" in the embodiments of the present application should not be construed as being more preferred or having more advantages than other embodiments or designs. Rather, the use of words such as "exemplarily" or "for example" is intended to present relevant concepts in a specific manner.

[0017] To solve the problems raised in the background art, the present invention provides a harmonic suppression circuit applied to a transmitter. The structure of the harmonic suppression circuit is as Figure 1 shown, including: a current source V, a first inductor L BW , a second inductor L CM , a capacitor C supply, a power amplifier PA, a balun BL, and an antenna T; the positive pole of the current source V is electrically connected to the first end of the first inductor L BW ; the second end of the first inductor L BW is electrically connected to one end of the capacitor C supply and the first end of the second inductor L CM ; the negative pole of the current source V is grounded, the negative pole of the capacitor C supply is grounded, and the second inductor L CM adjusts the common-mode impedance on the current source V side to suppress the harmonic components generated by the power amplifier PA; the second end of the second inductor L CM is electrically connected to the balun BL, and the position where the balun BL is electrically connected to the second inductor L CM is at the central position between the first end and the second end of the balun BL; the first end of the balun BL is electrically connected to the first output end of the power amplifier PA, and the second end of the balun BL is electrically connected to the second output end of the power amplifier PA; the third end of the balun BL is electrically connected to the antenna T, and the fourth end of the balun BL is grounded.

[0018] In the prior art, in order to stabilize the current source of the power amplifier, a large capacitor is connected in parallel to the current source of the power amplifier stage in the radio frequency transmitter. At this time, the current source is close to an ideal AC ground, and the suppression effect on the harmonic components generated by the power amplifier is weak. The purpose of the present invention is to suppress the harmonic components by adjusting the common-mode impedance of the power amplifier in the transmitter on the current source side, so that the energy of the current source is mainly consumed in the fundamental wave, thereby improving the transmission efficiency of the transmitter. Through the harmonic suppression circuit provided by the present invention, by connecting an inductor in parallel on the current source side, a good suppression effect on the harmonic components of the power amplifier can be achieved on the premise of ensuring the stability of the current signal. When a capacitor C supply is connected in parallel to the current source of the power amplifier and a common-mode inductor L CM is connected in series, for high-order harmonics, a common-mode impedance can be seen on the current source, and the ability to obtain energy from the current source is weakened. Therefore, the frequency component that mainly consumes energy is the fundamental wave, thereby achieving the purpose of improving efficiency. After adding the second inductor L CM , the electrical connection between structures is realized by routing a metal wire on the layout. In the prior art, the current source already needs to be routed from the PAD to the transformer. Therefore, a common-mode inductor can be realized without sacrificing area and the efficiency can be improved. The design of the present invention is simple and can improve the efficiency of the power amplifier without sacrificing area.

[0019] In some embodiments, such asFigure 2 As shown, the power amplifier includes: a first N-type transistor N1, a second N-type transistor N2, a third N-type transistor N3, and a fourth N-type transistor N4; the source of the first N-type transistor N1 is connected to the source of the second N-type transistor N2, and the source of the first N-type transistor N1 is grounded. The drain of the first N-type transistor N1 is connected to the source of the third N-type transistor N3; the drain of the second N-type transistor N2 is connected to the source of the fourth N-type transistor N4; the gate of the third N-type transistor N3 is connected to the gate of the fourth N-type transistor N4, and the drain of the third N-type transistor N3 is connected to the first end of the balun; the drain of the fourth N-type transistor N4 is connected to the second end of the balun. In Figure 2 , V1 and V2 are the input signals of the power amplifier, and V3 and V4 are the output signals of the power amplifier. The beneficial effects are as follows: The harmonic suppression circuit provided by the present invention has a good suppression effect on the harmonic components generated by the power amplifier of this structure. In the specific embodiment, only a power amplifier with a relatively simple structure is shown. In fact, the scope of application of the present invention is not limited thereto.

[0020] Based on the harmonic suppression circuit provided in the above embodiment, the present invention provides a transmitter, including the harmonic suppression circuit described in any one of the above embodiments. The transmitter further includes: a mixer, a low-pass filter, a digital-to-analog converter, a data processing module, and a phase-locked loop, a current management unit, and a temperature sensor that are matched with it. However, compared with the prior art, the mixer, the low-pass filter, the digital-to-analog converter, the data processing module, and the phase-locked loop, the current management unit, and the temperature sensor that are matched with it are prior art and not the inventive content of this application, so no more description will be made. The present invention only replaces the final-stage structure including the power amplifier in the prior art with the harmonic suppression circuit provided by the present invention. Therefore, the transmitter provided by the present invention can have a good suppression effect on the harmonic components generated by the power amplifier on the premise of ensuring the stability of the power supply current source of the power amplifier.

[0021] As described above, it is only the specific implementation manner of the embodiments of this application, but the protection scope of the embodiments of this application is not limited thereto. Any change or replacement within the technical scope disclosed in the embodiments of this application should be covered by the protection scope of the embodiments of this application. Therefore, the protection scope of the embodiments of this application should be subject to the protection scope of the claimed rights.

Claims

1. A harmonic suppression circuit, characterized in that, applied to a transmitter, comprising: a current source, a first inductor, a second inductor, a capacitor, a power amplifier, a balun, and an antenna; the positive pole of the current source is electrically connected to the first end of the first inductor, the second end of the first inductor is electrically connected to one end of the capacitor and the first end of the second inductor; the negative pole of the current source is grounded, the negative pole of the capacitor is grounded, and the second inductor adjusts the common-mode impedance on the current source side to suppress the harmonic components generated by the power amplifier; the second end of the second inductor is electrically connected to the balun, and the position where the balun is electrically connected to the second inductor is at the central position between the first end and the second end of the balun; the first end of the balun is electrically connected to the first output end of the power amplifier, and the second end of the balun is electrically connected to the second output end of the power amplifier; the third end of the balun is electrically connected to the antenna, and the fourth end of the balun is grounded.

2. The harmonic suppression circuit according to claim 1, characterized in that, the power amplifier comprises: a first N-type transistor, a second N-type transistor, a third N-type transistor, and a fourth N-type transistor; the source electrode of the first N-type transistor is connected to the source electrode of the second N-type transistor, the source electrode of the first N-type transistor is grounded, and the drain electrode of the first N-type transistor is connected to the source electrode of the third N-type transistor; the drain electrode of the second N-type transistor is connected to the source electrode of the fourth N-type transistor; the gate electrode of the third N-type transistor is connected to the gate electrode of the fourth N-type transistor, and the drain electrode of the third N-type transistor is connected to the first end of the balun; the drain electrode of the fourth N-type transistor is connected to the second end of the balun.

3. A transmitter, characterized in that, comprises the harmonic suppression circuit according to any one of claims 1 to 2.

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