Amplifier circuit and electronic equipment

Abstract

The embodiment of the utility model provides an amplifier circuit and electronic equipment, and relates to the technical field of amplifiers. During low-frequency operation, signals are amplified after passing through the two low-pass filters and do not enter the other two high-pass filters, fundamental wave amplitudes and phases are the same after two paths of synthesis of the second balun, but second harmonic amplitudes are the same, and the phase difference is 180 degrees, so that the second harmonic amplitudes in the synthesized waveform are offset, but the amplitudes of the fundamental waves are normal; therefore, the second harmonic suppression degree that the second harmonic of the low-frequency signal falls in the band when the low-frequency signal is input is optimized. During high-frequency operation, signals are amplified after passing through the two high-pass filters, and the signals do not enter the other two low-pass filters, so that normal operation of the circuit is ensured when low-frequency double-frequency signals are input. Moreover, the amplifier circuit provided by the embodiment of the utility model is insensitive to the process and design, and is beneficial to popularization and application.

Description

Technical Field

[0001] This application relates to the technical field of amplifiers, and particularly to amplifier circuits and electronic devices. Background Art

[0002] The conventional method for optimizing the narrowband second harmonic of an amplifier is to directly add a high-pass filter at the output of the amplifier to optimize the second harmonic, so that the second harmonic reaches a very high suppression ratio.

[0003] In a broadband amplifier, the second harmonics of some narrowband frequencies will fall within the band. In order to ensure the normal operation of the amplifier when inputting high-frequency signals, it cannot be suppressed by directly adding a filter, resulting in the second harmonic not reaching a very high suppression ratio.

[0004] How to suppress the second harmonic of the narrowband frequency points falling within the band and not affect the normal operation when inputting high-frequency signals is the technical problem to be solved by this application. Summary of the Utility Model

[0005] The purpose of this application is to provide an amplifier circuit and an electronic device to suppress the second harmonic of the narrowband frequency points falling within the band and not affect the normal operation when inputting high-frequency signals.

[0006] To achieve the above purpose, the embodiments of this application adopt the following technical solutions.

[0007] In a first aspect, an embodiment of this application provides an amplifier circuit, including: a first balun, a first low-pass filtering branch, a first high-pass filtering branch, a second low-pass filtering branch, a second high-pass filtering branch, and a second balun;

[0008] Amplifiers are included in the first low-pass filtering branch, the first high-pass filtering branch, the second low-pass filtering branch, and the second high-pass filtering branch;

[0009] The first balun is used to divide the input signal into a first signal and a second signal with a phase difference of 180 degrees, output the first signal at a first output end, and output the second signal at a second output end;

[0010] The first output end of the first balun is connected to the input ends of the first low-pass filtering branch and the first high-pass filtering branch;

[0011] The second output end of the first balun is connected to the input ends of the second low-pass filtering branch and the second high-pass filtering branch;

[0012] The output ends of the first low-pass filtering branch and the first high-pass filtering branch are connected to the first input end of the second balun;

[0013] The output end of the second low-pass filtering branch and the output end of the second high-pass filtering branch are connected to the second input end of the second balun;

[0014] The second balun is used to synthesize and output the signals of the first low-pass filtering branch, the first high-pass filtering branch, the second low-pass filtering branch, and the second high-pass filtering branch.

[0015] Optionally, the first low-pass filtering branch and the second low-pass filtering branch have the same structure.

[0016] Optionally, the first high-pass filtering branch and the second high-pass filtering branch have the same structure.

[0017] Optionally, the first low-pass filtering branch includes a first low-pass filter, a first amplifier, and a second low-pass filter;

[0018] The first low-pass filter, the first amplifier, and the second low-pass filter are connected in sequence; the input end of the first low-pass filter is connected to the first output end of the first balun; the output end of the second low-pass filter is connected to the first input end of the second balun.

[0019] Optionally, the second low-pass filtering branch includes a third low-pass filter, a second amplifier, and a fourth low-pass filter;

[0020] The third low-pass filter, the second amplifier, and the fourth low-pass filter are connected in sequence; the input end of the third low-pass filter is connected to the second output end of the first balun; the output end of the fourth low-pass filter is connected to the second input end of the second balun.

[0021] Optionally, the first low-pass filter and the third low-pass filter are the same, and the second low-pass filter and the fourth low-pass filter are the same.

[0022] Optionally, the first high-pass filtering branch includes a first high-pass filter, a third amplifier, and a second high-pass filter;

[0023] The first high-pass filter, the third amplifier, and the second high-pass filter are connected in sequence; the input end of the first high-pass filter is connected to the first output end of the first balun; the output end of the second high-pass filter is connected to the first input end of the second balun.

[0024] Optionally, the second high-pass filtering branch includes a third high-pass filter, a fourth amplifier, and a fourth high-pass filter;

[0025] The third high-pass filter, the fourth amplifier, and the fourth high-pass filter are connected in sequence; the input end of the third high-pass filter is connected to the second output end of the first balun; the output end of the fourth high-pass filter is connected to the second input end of the second balun.

[0026] Optionally, the first high-pass filter is the same as the third high-pass filter, and the second high-pass filter is the same as the fourth high-pass filter.

[0027] In a second aspect, an embodiment of the present application provides an electronic device, and the electronic device includes the amplifier circuit of the first aspect.

[0028] Compared with the prior art, the present application has the following beneficial effects:

[0029] The amplifier circuit provided by the embodiment of the present application converts a signal into an equally divided signal with a phase difference of 180° through the first balun;

[0030] When a low-frequency signal works, the signal is amplified after passing through two low-pass filters, and the signal does not enter the other two high-pass filters. After low-pass filtering and amplification, the fundamental wave signal amplitudes of the upper and lower signals are equal, and the phase difference is 180°, but the second harmonic phases are in phase. After the two-way synthesis through the second balun, the fundamental wave amplitudes are equal and the phases are the same, but the second harmonic amplitudes are equal and the phase difference is 180°. Therefore, the second harmonic amplitudes in the synthesized waveform are cancelled, but the fundamental wave amplitudes are normal, thereby optimizing the second harmonic suppression ratio of the low-frequency signal with the second harmonic falling within the band;

[0031] When a high-frequency signal (a double-frequency signal of the low frequency) works, the signal is amplified after passing through two high-pass filters, and the signal does not enter the other two low-pass filters. After being amplified by the high-pass filter, the fundamental wave phase difference of the high-frequency signals with a phase difference of 180° output by the amplifier is 180°. After the two-way synthesis through the second balun, the fundamental harmonic amplitudes are equal and the phases are the same. Therefore, the high-frequency signal works normally.

[0032] Therefore, the present application optimizes the second harmonic suppression ratio of the low-frequency signal with the second harmonic falling within the band when the low-frequency signal is input; at the same time, it ensures that the circuit works normally when the high-frequency signal (a double-frequency signal of the low frequency) is input. Moreover, the amplifier circuit provided by the embodiment of the present application is not sensitive to the process and design, which is conducive to popularization and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0034] Figure 1 Schematic diagram of an amplifier circuit provided by an embodiment of the present application;

[0035] Figure 2 Schematic diagram of a first low-pass filtering branch provided by an embodiment of the present application;

[0036] Figure 3 Schematic diagram of a first low-pass filtering branch and a second low-pass filtering branch formed by sequentially connecting a low-pass filter, an amplifier, and a low-pass filter provided by an embodiment of the present application;

[0037] Figure 4 Schematic diagram of a first high-pass filtering branch provided by an embodiment of the present application;

[0038] Figure 5 Schematic diagram of a first high-pass filtering branch and a second high-pass filtering branch formed by sequentially connecting a high-pass filter, an amplifier, and a high-pass filter provided by an embodiment of the present application.

[0039] Description of reference numerals:

[0040] 1 First balun

[0041] 2 First low-pass filtering branch

[0042] 3 First high-pass filtering branch

[0043] 4 Second low-pass filtering branch

[0044] 5 Second high-pass filtering branch

[0045] 6 Second balun

[0046] 7 First low-pass filter

[0047] 8 First amplifier

[0048] 9 Second low-pass filter

[0049] 10 Third low-pass filter

[0050] 11 Second amplifier

[0051] 12 Fourth low-pass filter

[0052] 13 First high-pass filter

[0053] 14 Third amplifier

[0054] 15 Second high-pass filter

[0055] 16 Third high-pass filter

[0056] 17 Fourth amplifier

[0057] 18th Fourth High-Pass Filter Detailed Implementation Manner

[0058] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. The described embodiments are some, but not all, of the embodiments of the present application. The components of the embodiments of the present application usually described in the accompanying drawings here can be arranged and designed in various different configurations.

[0059] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application claimed, but merely represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts fall within the scope of protection of the present application. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0060] In the description of the present application, it should be noted that relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. The term "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium.

[0061] To suppress the influence of the second harmonic of the amplifier, reference can be made to Figure 1 , an amplifier circuit is provided in an embodiment of the present application, which includes a first balun 1, a low-pass network, a high-pass network, and a second balun 6. The low-pass network includes a first low-pass filter branch 2 and a second low-pass filter branch 4; the high-pass network includes a first high-pass filter branch 3 and a second high-pass filter branch 5. Amplifiers are included in the first low-pass filter branch 2, the first high-pass filter branch 3, the second low-pass filter branch 4, and the second high-pass filter branch 5.

[0062] The main functions of a balun (Balanced to Unbalanced Transformer, Balun) include impedance transformation and balanced-to-unbalanced conversion. The two outputs of the balun have equal amplitudes and opposite phases. In the frequency domain, this means that there is a 180° phase shift between the two outputs; in the time domain, this means that the voltage of one balanced output is the negative value of the other balanced output.

[0063] The first balun 1 is used to divide the input signal RFIN into a first signal and a second signal with a phase difference of 180 degrees, output the first signal at the first output terminal, and output the second signal at the second output terminal;

[0064] The first output terminal of the first balun 1 is connected to the input terminal of the first low-pass filter branch 2 and the input terminal of the first high-pass filter branch 3;

[0065] The second output terminal of the first balun 1 is connected to the input terminal of the second low-pass filter branch 4 and the input terminal of the second high-pass filter branch 5;

[0066] The output terminal of the first low-pass filter branch 2 and the output terminal of the first high-pass filter branch 3 are connected to the first input terminal of the second balun 6;

[0067] The output terminal of the second low-pass filter branch 4 and the output terminal of the second high-pass filter branch 5 are connected to the second input terminal of the second balun 6;

[0068] The second balun 6 is used to synthesize the signals of the first low-pass filter branch 2, the first high-pass filter branch 3, the second low-pass filter branch 4 and the second high-pass filter branch 5 into a signal RFOUT and output it.

[0069] This amplifier circuit combines a differential balun and a high-low pass network. The signal is changed into an equally divided signal with a phase difference of 180° through the first balun. The signals with a difference of 180° are further divided into high-pass and low-pass filters. The second harmonics output by the amplifier are in the same phase. After the two-way synthesis through the second balun, the second harmonics have a phase difference of 180°. Therefore, the amplitudes of the second harmonics in the synthesized waveform are cancelled, thereby optimizing the second harmonic suppression ratio of the low-frequency signal with the second harmonic falling within the band.

[0070] If only the fully differential scheme is adopted, that is, using a differential balun without using a high-low pass network, the signals with a phase difference of 180° are not further divided into four paths of high-pass filter and low-pass filter. The insertion loss of the broadband balun is large and the performance in terms of noise is poor; at the same time, the amplitude-phase balance of the balun will affect the cancellation result of the second harmonics.

[0071] If only the low-pass network is adopted without using a differential balun, although the second harmonics generated by the low-frequency signal can be suppressed, the circuit cannot work properly when inputting high-frequency signals.

[0072] Therefore, on the basis of combining the two, the method of using a differential balun plus frequency bands is adopted: input signals in different frequency bands pass through high-low pass filters respectively. The low-frequency signal passes through a low-pass filter and an output balun to make the second harmonics have opposite phases and cancel each other in amplitude, suppressing the second harmonics; the high-frequency signal passes through a high-pass filter and an output balun to make the high-frequency fundamental waves have the same phase and equal amplitudes, ensuring that the high-frequency signal is not affected and can work properly. Finally, the value of the second harmonics after the synthesis of the balun and the high-low pass is lower, and at this time the second harmonic suppression ratio is improved.

[0073] Taking the circuit operating at 6 - 18 GHz as an example, the second harmonic of 6 - 9 GHz (12 - 18 GHz) is just within the band. If we want to improve the second harmonic of 6 - 9 GHz, we can design the low - end cut - off frequency of the low - pass network to be less than or equal to 6 GHz, and the high - end cut - off frequency of the low - pass network to be within 9 - 12 GHz. The low - end cut - off frequency of the high - pass network is less than or equal to the high - end cut - off frequency of the low - pass network and within 9 - 12 GHz.

[0074] The structures of the first low - pass filter branch 2 and the second low - pass filter branch 4 can be the same. The structures of the first high - pass filter branch 3 and the second high - pass filter branch 5 can be the same. This can simplify the design and balance the performance between different branches.

[0075] For example Figure 2 , the first low - pass filter branch 2 may include a first low - pass filter 7, a first amplifier 8, and a second low - pass filter 9.

[0076] The function of a low - pass filter (LPF) is to pass low - frequency signals and attenuate high - frequency signals.

[0077] Regarding the implementation principle of the low - pass filter, we can utilize the principle that a capacitor passes high - frequency signals and blocks low - frequency signals, or an inductor passes low - frequency signals and blocks high - frequency signals. For the high - frequency signals that need to be blocked, we can use the method of capacitor absorption and inductor impedance to prevent them from passing; for the low - frequency signals that need to be passed, we can utilize the characteristics of high impedance of the capacitor and low impedance of the inductor to let them pass.

[0078] The first low - pass filter 7, the first amplifier 8, and the second low - pass filter 9 have the following connection relationship: the first low - pass filter 7, the first amplifier 8, and the second low - pass filter 9 are connected in sequence; the input end of the first low - pass filter 7 is connected to the first output end of the first balun 1; the output end of the second low - pass filter 9 is connected to the first input end of the second balun 6.

[0079] Similar to the first low - pass filter branch 2, for example Figure 3 , the second low - pass filter branch 4 may include a third low - pass filter 10, a second amplifier 11, and a fourth low - pass filter 12.

[0080] The third low - pass filter 10, the second amplifier 11, and the fourth low - pass filter 12 have the following connection relationship: the third low - pass filter 10, the second amplifier 11, and the fourth low - pass filter 12 are connected in sequence; the input end of the third low - pass filter 10 is connected to the second output end of the first balun 1; the output end of the fourth low - pass filter 12 is connected to the second input end of the second balun 6.

[0081] Figure 3Among them, the first low-pass filter 7 and the third low-pass filter 10 are the same, and the second low-pass filter 9 and the fourth low-pass filter 12 are the same. The first low-pass filter 7 and the second low-pass filter 9 can be different, and the third low-pass filter 10 and the fourth low-pass filter 12 can be different, which facilitates the design and implementation of the required performance.

[0082] As Figure 4 , the first high-pass filter branch 3 may include a first high-pass filter 13, a third amplifier 14, and a second high-pass filter 15.

[0083] The function of a high-pass filter (HPF) is to pass high-frequency signals and attenuate low-frequency signals.

[0084] For the implementation principle of a high-pass filter, the principle that a capacitor passes high frequencies and blocks low frequencies can be utilized. For extremely high frequencies, the capacitor is equivalent to a "short circuit", and these frequencies can all obtain an output across the resistor.

[0085] The first high-pass filter 13, the third amplifier 14, and the second high-pass filter 15 have the following connection relationship: the first high-pass filter 13, the third amplifier 14, and the second high-pass filter 15 are connected in sequence; the input end of the first high-pass filter 13 is connected to the first output end of the first balun 1; the output end of the second high-pass filter 15 is connected to the first input end of the second balun 6.

[0086] Similar to the first high-pass filter 13, as Figure 5 , the second high-pass filter branch 5 may include a third high-pass filter 16, a fourth amplifier 17, and a fourth high-pass filter 18.

[0087] The third high-pass filter 16, the fourth amplifier 17, and the fourth high-pass filter 18 have the following relationship: the third high-pass filter 16, the fourth amplifier 17, and the fourth high-pass filter 18 are connected in sequence; the input end of the third high-pass filter 16 is connected to the second output end of the first balun 1; the output end of the fourth high-pass filter 18 is connected to the second input end of the second balun 6.

[0088] Figure 5 Among them, the first high-pass filter 13 and the third high-pass filter 16 are the same, and the second high-pass filter 15 and the fourth high-pass filter 18 are the same. The first high-pass filter 13 and the second high-pass filter 15 can be different, and the third high-pass filter 16 and the fourth high-pass filter 18 can be different, which facilitates the design and implementation of the required performance.

[0089] Based on the above embodiments, the embodiments of the present application further provide an electronic device, and the electronic device includes the above amplifier circuit.

[0090] Generally speaking, the present application proposes an amplifier circuit and an electronic device. The signal is converted into two equal - divided signals with a phase difference of 180° by the first balun. Each of the two signals is further divided into a high - pass and a low - pass filter, resulting in a total of four signals. The second - harmonic phases of the four signals output by the amplifier are in phase. After the two - way synthesis by the second balun, the second - harmonic phases differ by 180°. Therefore, the amplitudes of the second - harmonics in the synthesized waveform cancel each other out, thereby optimizing the second - harmonic suppression ratio of the low - frequency signals with the second - harmonics falling within the band. Moreover, the amplifier circuit provided in the embodiments of the present application is not sensitive to the process and design, which is conducive to popularization and application.

[0091] The device and system embodiments described above are merely illustrative. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative efforts.

[0092] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An amplifier circuit, characterized in that: include: A first balun, a first low-pass filter branch, a first high-pass filter branch, a second low-pass filter branch, a second high-pass filter branch, and a second balun; The first low-pass filter branch, the first high-pass filter branch, the second low-pass filter branch and the second high-pass filter branch all include amplifiers; The first balun is used to divide the input signal into a first signal and a second signal with a phase difference of 180 degrees, and output the first signal at a first output terminal and output the second signal at a second output terminal; The first output end of the first balun is connected to the input end of the first low-pass filter branch and the input end of the first high-pass filter branch; The second output end of the first balun is connected to the input end of the second low-pass filter branch and the input end of the second high-pass filter branch; An output end of the first low-pass filter branch and an output end of the first high-pass filter branch are connected to a first input end of the second balun; An output end of the second low-pass filter branch and an output end of the second high-pass filter branch are connected to a second input end of the second balun; The second balun is used to synthesize and output the signals of the first low-pass filter branch, the first high-pass filter branch, the second low-pass filter branch and the second high-pass filter branch.

2. The amplifier circuit according to claim 1, characterized in that The first low-pass filter branch and the second low-pass filter branch have the same structure.

3. The amplifier circuit according to claim 1, wherein: The first high-pass filter branch and the second high-pass filter branch have the same structure.

4. The amplifier circuit according to claim 1, wherein: The first low-pass filter branch includes a first low-pass filter, a first amplifier and a second low-pass filter; The first low-pass filter, the first amplifier and the second low-pass filter are connected in sequence; the input end of the first low-pass filter is connected to the first output end of the first balun; the output end of the second low-pass filter is connected to the first input end of the second balun.

5. The amplifier circuit according to claim 4, characterized in that The second low-pass filter branch includes a third low-pass filter, a second amplifier and a fourth low-pass filter; The third low-pass filter, the second amplifier and the fourth low-pass filter are connected in sequence; the input end of the third low-pass filter is connected to the second output end of the first balun; the output end of the fourth low-pass filter is connected to the second input end of the second balun.

6. The amplifier circuit according to claim 5, characterized in that The first low-pass filter is the same as the third low-pass filter, and the second low-pass filter is the same as the fourth low-pass filter.

7. The amplifier circuit according to claim 1, wherein: The first high-pass filter branch includes a first high-pass filter, a third amplifier and a second high-pass filter; The first high-pass filter, the third amplifier and the second high-pass filter are connected in sequence; the input end of the first high-pass filter is connected to the first output end of the first balun; the output end of the second high-pass filter is connected to the first input end of the second balun.

8. The amplifier circuit according to claim 7, characterized in that The second high-pass filter branch includes a third high-pass filter, a fourth amplifier and a fourth high-pass filter; The third high-pass filter, the fourth amplifier and the fourth high-pass filter are connected in sequence; the input end of the third high-pass filter is connected to the second output end of the first balun; the output end of the fourth high-pass filter is connected to the second input end of the second balun.

9. The amplifier circuit according to claim 8, characterized in that The first high-pass filter is the same as the third high-pass filter, and the second high-pass filter is the same as the fourth high-pass filter.

10. An electronic device, characterized in that: The electronic device comprises the amplifier circuit according to any one of claims 1 to 9.

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