Low noise amplifier and radio frequency module
By adopting the technology of time-sharing conduction of the first and second active paths in the low noise amplifier, the combination of gain adjustability and phase continuity is achieved, and the problem of adjustable gain but difficult to guarantee linearity and phase continuity in the prior art is solved.
Patent Information
- Application Number
- CN202411635770.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-15
- Publication Date
- 2025-02-25
AI Technical Summary
While achieving adjustable gain of low-noise amplifiers, it is difficult to maintain good linearity and phase continuity, especially in the 5G era, the performance requirements for RF front-end are getting higher and higher.
The first active path and the second active path are time-shared, and the input circuit and the output circuit are shared. The gain range of the first active path is at least partially larger than the gain range of the second active path, and the same-phase output of the signal is realized through different configurations of the amplifier tube.
The adjustability of the gain of the low noise amplifier is achieved, while ensuring the phase continuity of the output signal at different gain gears, and achieving better linearity in the low gain gears.
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Figure CN119519615A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of radio frequency technology, and in particular to a low noise amplifier and a radio frequency module. Background Art
[0002] RF module refers to RF front-end module (back-end is often discrete devices). Previously, since the use of discrete devices in the RF front-end can also meet the needs of some manufacturers, there was a clear distinction between high-end equipment using RF modules and low-end equipment using discrete devices. RF modules can provide higher integration and high performance. In the 5G era, due to the sharp increase in the number of RF components in a single product, the area occupied by discrete device solutions exceeds the acceptable limit, and the debugging time will be longer. Therefore, RF front-end modularization has become a development trend in the mobile communication market. RF modules are divided into FEMiD (integrated switch, filter and duplexer), PAMiD (integrated multi-mode multi-band power amplifier PA and FEMiD), LPAMiD (integrated PAMiD and low noise amplifier LNA), DiFEM (integrated RF switch and filter), LFEM (integrated RF switch, low noise amplifier LNA and filter), etc.
[0003] As an important component in the RF module, the low noise amplifier (LNA) is an active module and is critical to the performance of the receiver system. It is used to obtain and amplify extremely weak uncertain signals from the antenna, while also identifying noise. Its main parameters include noise figure, gain, input-output matching, linearity, reverse isolation, etc.
[0004] In consumer electronics applications, the LNA of the RF front end needs to meet the requirements of a large dynamic signal reception range to be able to receive signals of different strengths. It needs to have sufficient amplification capabilities when receiving weak signals and sufficient linearity when receiving large signals to ensure that the signal is not distorted. In addition, the LNA is required to be able to achieve different gain adjustments to meet the requirements of receiving gain and linearity for receiving signals of different strengths. For example, the gain range can be adjustable from below -10dB to 20dB gain in multiple gears. Some platforms also require that the continuity of the phase can be guaranteed at different gain gears.
[0005] Therefore, while achieving adjustable LNA gain, factors such as linearity and phase also need to be considered comprehensively to maintain good overall performance. Summary of the invention
[0006] In order to solve the above technical problems, the embodiments of the present application provide a low noise amplifier and a radio frequency module to achieve adjustable gain of the low noise amplifier while maintaining good overall performance such as linearity and phase.
[0007] To achieve the above objectives, the present application provides the following technical solutions:
[0008] A low noise amplifier comprises a first active path and a second active path, wherein the first active path and the second active path share an input circuit and an output circuit;
[0009] The first active path and the second active path are turned on in a time-sharing manner, and the input signal is amplified in the first active path or in the second active path after passing through the input circuit, and then outputted through the output circuit;
[0010] The gain range of the first active path is at least partially greater than the gain range of the second active path;
[0011] The signal output by the first active path and the signal output by the second active path are in phase.
[0012] Optionally, the first active path includes the input circuit, the first amplifier tube, the first switch, the second amplifier tube and the output circuit connected in sequence along the signal transmission direction;
[0013] The input circuit includes a first inductor and a first capacitor, wherein the first end of the first inductor is a signal input end, the second end of the first inductor is electrically connected to the first end of the first capacitor, and the second end of the first capacitor is electrically connected to the control end of the first amplifier tube;
[0014] The control end of the first amplifier tube is also connected to the first bias voltage through the first resistor; the first end of the first amplifier tube is electrically connected to the first end of the first switch; the second end of the first amplifier tube is grounded through the feedback circuit; the first amplifier tube is used to invert and amplify the signal;
[0015] The control end of the second amplifier tube is connected to the second bias voltage through the second resistor and is grounded through the second capacitor; the first end of the second amplifier tube is connected to the power supply voltage through the second inductor and is electrically connected to the first end of the output circuit; the second end of the second amplifier tube is electrically connected to the second end of the first switch; the second amplifier tube is used to amplify the signal in phase; the second end of the output circuit is a signal output end;
[0016] The first inductor, the first capacitor, the first resistor, the first amplifier tube and the feedback circuit constitute an input matching network of the first active path.
[0017] Optionally, the second active path includes the input circuit, the second switch, the first attenuation circuit, the third capacitor, the third amplifier tube, the third switch, the fourth amplifier tube and the output circuit connected in sequence along the signal transmission direction;
[0018] The first end of the second switch is electrically connected to the second end of the first capacitor in the input circuit, the second end of the second switch is electrically connected to the first end of the first attenuation circuit, the second end of the first attenuation circuit is electrically connected to the first end of the third capacitor, and the second end of the third capacitor is electrically connected to the control end of the third amplifier tube;
[0019] The control end of the third amplifier tube is also connected to the third bias voltage through the third resistor; the first end of the third amplifier tube is electrically connected to the first end of the third switch; the second end of the third amplifier tube is electrically connected to the end of the feedback circuit away from the ground through the fourth switch; the third amplifier tube is used to invert the signal;
[0020] The control end of the fourth amplifier tube is connected to the fourth bias voltage through the fourth resistor and is grounded through the fourth capacitor; the first end of the fourth amplifier tube is connected to the power supply voltage through the second inductor and is electrically connected to the first end of the output circuit; the second end of the second amplifier tube is electrically connected to the second end of the third switch; the second amplifier tube is used to amplify the signal in phase;
[0021] The first inductor, the first capacitor, the third capacitor, the third resistor, the third amplifier tube and the feedback circuit constitute an input matching network of the second active path.
[0022] Optionally, a fifth capacitor is electrically connected between the control end and the second end of the third amplifier tube;
[0023] The first inductor, the first capacitor, the third capacitor, the third resistor, the fifth capacitor, the third amplifier tube and the feedback circuit constitute an input matching network of the second active path.
[0024] Optionally, the second switch tube is multiplexed as the fourth switch tube, the second resistor is multiplexed as the fourth resistor, the second capacitor is multiplexed as the fourth capacitor, and the second bias voltage is multiplexed as the fourth bias voltage.
[0025] Optionally, the low noise amplifier further includes a passive path, and the first active path, the second active path and the passive path share the input circuit and the output circuit;
[0026] The first active path, the second active path and the passive path are turned on in a time-sharing manner, and the input signal is amplified in the first active path, or in the second active path, or in the passive path after passing through the input circuit, and then outputted through the output circuit;
[0027] The gain range of the passive path and the gain range of the second active path at least partially overlap.
[0028] Optionally, the passive path includes the input circuit, the fifth switch, the second attenuation circuit, the sixth capacitor and the output circuit connected in sequence along the signal transmission direction;
[0029] The first end of the fifth switch is electrically connected to the second end of the first capacitor in the input circuit, the second end of the fifth switch is electrically connected to the first end of the second attenuation circuit, the second end of the second attenuation circuit is electrically connected to the first end of the sixth capacitor, and the second end of the sixth capacitor is connected to the first end of the output circuit.
[0030] Optionally, a common end connected to the first inductor and the first capacitor is grounded through a third attenuation circuit.
[0031] Optionally, the first attenuation circuit in the second active path and / or the second attenuation circuit in the passive path are multiplexed as an attenuation circuit at a signal input end.
[0032] A radio frequency module comprises the low noise amplifier described in any one of the above items.
[0033] Compared with the prior art, the above technical solution has the following advantages:
[0034] The low noise amplifier provided in the embodiment of the present application includes a first active path and a second active path, the first active path and the second active path share an input circuit network and an output circuit, the gain range of the first active path is at least partially greater than the gain range of the second active path, so that when the first active path and the second active path are turned on in time-sharing, the low noise amplifier can have different gain gears, for example, when the first active path is turned on, a medium-high gain gear can be achieved, and when the second active path is turned on, a medium-low gain gear can be achieved, thereby achieving adjustable gain; and the first active path and the second active path are both active paths, and the amplification mode of the first active path and the second active path can be controlled, so that the signal output by the first active path and the signal output by the second active path are in phase, thereby ensuring the phase continuity of the output signal at different gain gears; in addition, the second active path with a relatively low gain gear can also obtain better linearity; in summary, the low noise amplifier provided in the embodiment of the present application can meet the requirements of adjustable gain while meeting the requirements of phase continuity and linearity at different gain gears.
[0035] Furthermore, the first active path and the second active path can reuse the amplifier tube, which can reduce the layout area of the low noise amplifier, reduce power consumption and cost.
[0036] Furthermore, considering that the passive path has high linearity when achieving a low gain gear, the low noise amplifier provided in the embodiment of the present application can also add a passive path, the first active path, the second active path and the passive path share an input circuit and an output circuit, and the gain range of the passive path and the gain range of the second active path at least partially overlap, so that when the passive path is turned on, a low gain gear can be achieved with high linearity, so that, in the case of a phase continuity requirement, the first active path and the second active path can be turned on in time-sharing manner to meet the gain adjustment while ensuring phase continuity, and having better linearity at a low gain gear; in the case of no phase continuity requirement, the first active path and the passive path can be turned on in time-sharing manner, or the first active path, the second active path and the passive path can be turned on in time-sharing manner to meet the gain adjustment while having high linearity at a low gain gear. BRIEF DESCRIPTION OF THE DRAWINGS
[0037] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0038] Figure 1 The present invention is a schematic diagram of the circuit structure of an existing gain-adjustable low-noise amplifier;
[0039] Figure 2 It is a circuit structure schematic diagram of another existing gain-adjustable low-noise amplifier;
[0040] Figure 3 The present invention is a schematic diagram of the circuit structure of another existing gain-adjustable low-noise amplifier;
[0041] Figure 4 A schematic diagram of the circuit structure of a low noise amplifier provided in an embodiment of the present application;
[0042] Figure 5 A schematic diagram of the circuit structure of another low noise amplifier provided in an embodiment of the present application. DETAILED DESCRIPTION
[0043] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.
[0044] In the following description, many specific details are set forth to facilitate a full understanding of the present application, but the present application may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.
[0045] As described in the background technology section, while achieving adjustable LNA gain, factors such as linearity and phase also need to be considered comprehensively to maintain good overall performance.
[0046] Figure 1 A schematic diagram of the circuit structure of an existing gain-adjustable low-noise amplifier is shown in FIG. Figure 1 As shown, the low noise amplifier uses an active path and a passive path to achieve the adjustment of high and low gain gears, wherein the active path is used to achieve the high gain gear, and the passive path is used to achieve the low gain gear. The advantage of the passive path to achieve the low gain gear is that it has a higher linearity. At the same time, the passive path can be used as a feedback circuit and work simultaneously with the active path. By adjusting the resistance and capacitance in the passive path, different feedback depths can be achieved to achieve the purpose of gain adjustment. However, if there is a need for phase continuity, it is necessary to add a phase shift circuit to the active path or the passive path. The circuit structure is as follows: Figure 2 As shown, the requirement of phase continuity under different gears is achieved, while adding a phase shifting circuit will increase the layout area, thereby increasing power consumption and cost.
[0047] Figure 3 A schematic diagram of the circuit structure of another existing gain-adjustable low-noise amplifier is shown. Figure 3 As shown, the low noise amplifier uses an active path to directly achieve high and low gain adjustment. Specifically, the number, size and bias of the sub-amplifier tubes connected in parallel in the amplifier tube can be adjusted, and the gain can be adjusted by introducing an attenuation circuit at the output end and at the input end. While satisfying the gain adjustment, it also meets the requirements of phase continuity under different gain gears. However, the linearity of the active path is poor when achieving a low gain gear, and there is additional power consumption.
[0048] In view of this, an embodiment of the present application provides a low noise amplifier. Figure 4 A schematic diagram of the circuit structure of a low noise amplifier provided in an embodiment of the present application is shown. Figure 4As shown, the low noise amplifier includes a first active path 100 and a second active path 200. The first active path 100 and the second active path 200 share an input circuit 10 and an output circuit 20. The first active path 100 and the second active path 200 are turned on in a time-sharing manner. In this way, after the input signal passes through the input circuit 10, it is amplified in the first active path 100, or amplified in the second active path 200, and then output through the output circuit 20.
[0049] In the embodiment of the present application, the gain range of the first active path 100 is at least partially greater than the gain range of the second active path 200. Thus, when the first active path 100 and the second active path 200 are turned on in a time-sharing manner, the low noise amplifier can have different gain gears. For example, when the first active path 100 is turned on, a medium-high gain gear can be achieved, and when the second active path 200 is turned on, a medium-low gain gear can be achieved, thereby achieving adjustable gain.
[0050] Furthermore, the first active path 100 and the second active path 200 are both active paths, and the amplification modes of the first active path 100 and the second active path 200 can be controlled so that the signal output by the first active path 100 and the signal output by the second active path 200 are in phase, thereby ensuring the phase continuity of the output signal at different gain levels; in addition, the second active path 200 with a relatively low gain level can also obtain better linearity.
[0051] In summary, the low noise amplifier provided in the embodiment of the present application can satisfy the requirements of adjustable gain while meeting the requirements of phase continuity and linearity at different gain levels.
[0052] Optional, such as Figure 4 As shown, the first active path 100 includes an input circuit 10, a first amplifier tube T1, a first switch K1, a second amplifier tube T2 and an output circuit 20 which are sequentially connected along the signal transmission direction;
[0053] The input circuit 10 includes a first inductor L1 and a first capacitor C1, a first end of the first inductor L1 is a signal input end RFIN of the low noise amplifier, a second end of the first inductor L1 is electrically connected to a first end of the first capacitor C1, and a second end of the first capacitor C1 is electrically connected to a control end of the first amplifier tube T1;
[0054] The control end of the first amplifier tube T1 is also connected to the first bias voltage Vbias through the first resistor R1; the first end of the first amplifier tube T1 is electrically connected to the first end of the first switch K1; the second end of the first amplifier tube T1 is grounded through the feedback circuit 30; it can be seen that the signal at the control end of the first amplifier tube T1 is amplified by the first amplifier tube T1 and output from the first end of the first amplifier tube T1, and the first amplifier tube T1 is used to invert the signal;
[0055] The control end of the second amplifier tube T2 is connected to the second bias voltage Vcas1 through the second resistor R2, and is grounded through the second capacitor C2; the first end of the second amplifier tube T2 is connected to the power supply voltage VDD through the second inductor L2, and is electrically connected to the first end of the output circuit 20; the second end of the output circuit 20 is the signal output end RFOUT of the low noise amplifier; the second end of the second amplifier tube T2 is electrically connected to the second end of the first switch K1; it can be seen that when the first switch K1 is closed, the signal output from the first end of the first amplifier tube T1 is transmitted to the second end of the second amplifier tube T2, and after being amplified by the second amplifier tube T2, it is output from the first end of the second amplifier tube T2 to the output circuit 20, and is output from the signal output end RFOUT after passing through the output circuit 20. The second amplifier tube T2 is used to amplify the signal in phase.
[0056] like Figure 4 As shown, the first inductor L1, the first capacitor C1, the first resistor R1, the first amplifier T1 (mainly the parasitic capacitor Cgs1 of the first amplifier T1) and the feedback circuit 30 constitute the input matching network of the first active path 100. The input matching network of the first active path 100 is a typical source degeneration structure.
[0057] It should be noted that if the parasitic capacitance Cgs1 of the first amplifier tube T1 is insufficient, a capacitance may be added between the control terminal and the second terminal of the first amplifier tube T1 , depending on the specific situation.
[0058] It can be understood that the input matching network of the first active path 100 is responsible for effectively transmitting the signal received by the signal input terminal RFIN to the first active path 100 for amplification, and can play a role in signal matching and transmission, noise suppression, gain and linearity optimization, and reverse isolation improvement.
[0059] like Figure 4 As shown, when the first switch K1 is closed, the first active path 100 is turned on; when the first switch K1 is turned off, the first active path 100 is turned off.
[0060] It can be understood that when the first active path 100 is turned on, the phase of the signal inputted from the signal input terminal RFIN remains unchanged after passing through the input circuit 10, and then the signal is amplified by the first amplifier tube T1. After the signal of the control terminal of the first amplifier tube T1 is amplified by the first amplifier tube T1, the phase of the signal outputted from the first terminal of the first amplifier tube T1 is inverted, that is, the first amplifier tube T1 performs inverted amplification on the signal, and the signal outputted from the first terminal of the first amplifier tube T1 further reaches the second terminal of the second amplifier tube T2. After amplification by the second amplifier tube T2, the phase of the signal outputted from the first terminal of the second amplifier tube T1 remains unchanged, that is, the second amplifier tube T2 performs in-phase amplification on the signal, and the signal after the inverted amplification by the first amplifier tube T1 and the in-phase amplification by the second amplifier tube T2 is finally transmitted to the signal output terminal RFOUT by the output circuit 20. In this way, the phase of the signal outputted from the signal output terminal RFOUT is inverted with respect to the phase of the signal inputted from the signal input terminal RFIN.
[0061] It should be noted that the first amplifier tube T1 may be a single amplifier tube or may include a plurality of sub-amplifier tubes connected in parallel. When the first amplifier tube T1 includes a plurality of sub-amplifier tubes connected in parallel, the gain of the first active path 100 may be adjusted by adjusting the number of sub-amplifier tubes connected in the first amplifier tube T1. Of course, the gain of the first active path 100 may also be adjusted by adjusting the magnitude of the first bias voltage Vbias1 connected to the first amplifier tube T1 through the first resistor R1.
[0062] Similarly, the second amplifier tube T2 may be a single amplifier tube or may include a plurality of sub-amplifier tubes connected in parallel. When the second amplifier tube T2 includes a plurality of sub-amplifier tubes connected in parallel, the gain of the first active path 100 may be adjusted by adjusting the number of sub-amplifier tubes connected in the second amplifier tube T2. Of course, the gain of the first active path 100 may also be adjusted by adjusting the magnitude of the second bias voltage Vcas1 connected to the second amplifier tube T1 through the second resistor R2.
[0063] like Figure 4 As shown, the output circuit 20 is the output matching network of the first active path 100. The output matching network of the first active path 100 is responsible for effectively transmitting the signal amplified by the first active path 100 to the signal output terminal RFOUT, and can play multiple roles such as signal matching and transmission, noise suppression and isolation, stability and gain flatness, output power and efficiency optimization, impedance transformation and signal conditioning. The gain of the first active path 100 can also be adjusted by adjusting the output circuit 20.
[0064] Optional, such as Figure 4As shown, the second active path 200 includes an input circuit 10, a second switch K2, a first attenuation circuit 210, a third capacitor C3, a third amplifier tube T3, a third switch K3, a fourth amplifier tube T4 and an output circuit 20 which are sequentially connected along the signal transmission direction;
[0065] The first end of the second switch K2 is electrically connected to the second end of the first capacitor C1 in the input circuit 10, the second end of the second switch K2 is electrically connected to the first end of the first attenuation circuit 210, the second end of the first attenuation circuit 210 is electrically connected to the first end of the third capacitor C3, and the second end of the third capacitor C3 is electrically connected to the control end of the third amplifier tube T3;
[0066] The control end of the third amplifier tube T3 is also connected to the third bias voltage Vbias through the third resistor R3; the first end of the third amplifier tube T3 is electrically connected to the first end of the third switch K3; the second end of the third amplifier tube T3 is electrically connected to the end of the feedback circuit 30 away from the ground through the fourth switch K4; it can be seen that when the second switch K2 is closed, the signal input by the signal input end RFIN is transmitted to the control end of the third amplifier tube T3 through the input circuit 10, the second switch K2, the first attenuation circuit 210 and the third capacitor C3 in sequence, and the signal at the control end of the third amplifier tube T3 is amplified by the third amplifier tube T3 and output from the first end of the third amplifier tube T3. The third amplifier tube T3 is used to perform inverse amplification on the signal;
[0067] The control end of the fourth amplifier tube T4 is connected to the fourth bias voltage Vcas2 through the fourth resistor R4, and is grounded through the fourth capacitor C4; the first end of the fourth amplifier tube T4 is connected to the power supply voltage VDD through the second inductor L2, and is electrically connected to the first end of the output circuit 20; the second end of the fourth amplifier tube T4 is electrically connected to the second end of the third switch K3; therefore, it can be seen that when the second switch K2 and the third switch K3 are closed, the signal output from the first end of the third amplifier tube T3 is transmitted to the second end of the fourth amplifier tube T4, and after being amplified by the fourth amplifier tube T4, the signal is output from the first end of the fourth amplifier tube T4 to the output circuit 20, and is output from the signal output end RFOUT after passing through the output circuit 20. The fourth amplifier tube T4 is used for performing in-phase amplification on the signal.
[0068] like Figure 4 As shown, the first inductor L1, the first capacitor C1, the third capacitor C3, the third resistor R3, the third amplifier tube T3 (mainly referring to the parasitic capacitor Cgs3 of the third amplifier tube T3) and the feedback circuit 30 constitute the input matching network of the second active circuit 200. The input matching network of the second active circuit 200 is a typical source degeneration structure.
[0069] It should be noted that if Figure 4As shown, if the parasitic capacitance Cgs2 of the third amplifier tube T3 is not enough, a capacitance may be added between the control end and the second end of the third amplifier tube T3. For example, a fifth capacitor C5 is electrically connected between the control end and the second end of the third amplifier tube T3. At this time, the first inductor L1, the first capacitor C1, the third capacitor C3, the third resistor R3, the fifth capacitor C5, the third amplifier tube T3 (mainly the parasitic capacitance Cgs3 of the third amplifier tube T3) and the feedback circuit 30 constitute the input matching network of the second active circuit 200. In this way, the parasitic capacitance Cgs3 of the third amplifier tube T3 combined with the adjustment of the external fifth capacitor C5 can achieve a balance between input matching and noise matching. By adjusting the external fifth capacitor C5, it is possible to select whether to give priority to noise matching or input matching, or to compromise between input matching and noise matching.
[0070] It can be understood that the input matching network of the second active circuit 200 is responsible for effectively transmitting the signal received by the signal input terminal RFIN to the second active path 200 for amplification, and can play a role in signal matching and transmission, noise suppression, gain and linearity optimization, and reverse isolation improvement.
[0071] like Figure 4 As shown, when the second switch K2 and the third switch K3 are closed, the second active path 200 is turned on, and the fourth switch K4 also needs to be closed at this time, so that the second end of the third switch tube T3 is grounded through the feedback circuit 30; when the first switch K2 and / or the third switch K3 are turned off, the second active path 200 is turned off.
[0072] It can be understood that when the second active path 200 is turned on, the phase of the signal inputted from the signal input terminal RFIN does not change after passing through the input circuit 10, and the phase does not change after passing through the second switch K2, the first attenuation circuit 210 and the third capacitor C3. The third capacitor C3 plays an isolating role, and then the signal is amplified by the third amplifier tube T3. After the signal at the control end of the third amplifier tube T3 is amplified by the third amplifier tube T3, the phase of the signal outputted from the first end of the third amplifier tube T3 is inverted, that is, the third amplifier tube T3 performs inverted amplification on the signal, and the signal outputted from the first end of the third amplifier tube T3 further reaches the second end of the fourth amplifier tube T4. After amplification by the fourth amplifier tube T4, the phase of the signal outputted from the first end of the fourth amplifier tube T4 does not change, that is, the fourth amplifier tube T4 performs in-phase amplification on the signal. After the inverted amplification by the third amplifier tube T3 and the in-phase amplification by the fourth amplifier tube T4, the signal is finally transmitted to the signal output terminal RFOUT by the output circuit 20. In this way, the phase of the signal outputted from the signal output terminal RFOUT is inverted with respect to the phase of the signal inputted from the signal input terminal RFIN. It can be seen that the signal output by the first active path 100 and the signal output by the second active path 200 are in phase.
[0073] It should be noted that the third amplifier tube T3 may be a single amplifier tube or may include a plurality of sub-amplifier tubes connected in parallel. When the third amplifier tube T3 includes a plurality of sub-amplifier tubes connected in parallel, the gain of the second active path 200 may be adjusted by adjusting the number of sub-amplifier tubes connected in the third amplifier tube T3. Of course, the gain of the second active path 200 may also be adjusted by adjusting the magnitude of the third bias voltage Vbias2 connected to the third amplifier tube T3 through the third resistor R3.
[0074] Similarly, the fourth amplifier tube T4 may be a single amplifier tube or may include a plurality of sub-amplifier tubes connected in parallel. When the fourth amplifier tube T4 includes a plurality of sub-amplifier tubes connected in parallel, the gain of the second active path 200 may be adjusted by adjusting the number of sub-amplifier tubes connected in the fourth amplifier tube T4. Of course, the gain of the second active path 200 may also be adjusted by adjusting the magnitude of the fourth bias voltage Vcas2 connected to the fourth amplifier tube T4 through the fourth resistor R4.
[0075] It should also be noted that since the first active path 100 is a medium-high gain path and the second active path 200 is a medium-low gain path, the medium-high gain path pays more attention to noise and has relatively low linearity requirements, while the medium-low gain path pays more attention to linearity and has relatively low noise requirements. Therefore, in the first active path 100, the amplifier tube can adopt a SOI (Silicon-On-Insulator) MOS tube with a floating body effect. This is because, in the SOI MOS tube with a floating body effect, the silicon layer and the substrate are separated by an insulating layer, and the charge in the silicon layer cannot be directly discharged through the substrate, resulting in the potential in the silicon layer (i.e., the floating body potential) can float, there is no fixed potential, there is a liner bias effect, and the threshold voltage changes with the drain potential, so the linearity is relatively poor, but the parasitics of the source, drain and gate terminals relative to the silicon layer are very small, the cut-off frequency is very high, and the noise factor is negatively correlated with the cut-off frequency. The higher the cut-off frequency, the smaller the noise factor. Conversely, in the second active path 100, the amplifier tube can adopt a body contact SOI MOS tubes have better linearity and lower noise requirements.
[0076] like Figure 4 As shown, the output circuit 20 is the output matching network of the second active path 200. The output matching network of the second active path 200 is responsible for effectively transmitting the signal amplified by the second active path 200 to the signal output terminal RFOUT, and can play multiple roles such as signal matching and transmission, noise suppression and isolation, stability and gain flatness, output power and efficiency optimization, impedance transformation and signal conditioning. The gain of the second active path 200 can also be adjusted by adjusting the output circuit 20.
[0077] like Figure 4 As shown, the gain of the second active path 200 can also be adjusted by adjusting the first attenuation circuit 210. Optionally, the first attenuation circuit 210 adopts a π-type structure, that is, the first attenuation circuit 210 includes a resistor R11, a resistor R12, and a resistor R13, wherein the resistor R11 is located in the second active path 200, one end of the resistor R11 is grounded through the resistor R12, and the other end of the resistor R11 is grounded through the resistor R13, but the circuit structure of the first attenuation circuit 210 is not limited to the π-type structure, and can also be a T-type structure, a resistor network structure, etc.
[0078] Optionally, the second amplifier tube T2 in the first active path 100 is multiplexed as the fourth amplifier tube T4 in the second active path 200, the second resistor R2 in the first active path 100 is multiplexed as the fourth resistor R4 in the second active path 200, and the second capacitor C2 in the first active path 100 is multiplexed as the fourth capacitor C4 in the second active path 200. Naturally, the second bias voltage Vcas1 is multiplexed as the fourth bias voltage Vcas2. In this way, the low-noise amplifier omits an amplifier tube, a capacitor and a resistor, which can greatly reduce the layout area of the low-noise amplifier and save power consumption and cost.
[0079] Alternatively, the fourth amplifier tube T4, the fourth resistor R4 and the fourth capacitor C4 in the second active path 200 can also be independently set, that is, the second amplifier tube T2, the second resistor R2 and the second capacitor C2 in the first active path 100 are not reused. Naturally, the fourth bias voltage Vcas2 is also independent of the second bias voltage Vcas1.
[0080] From the above circuit analysis of the first active path 100 and the second active path 200, it can be seen that the signal output by the first active path 100 and the signal output by the second active path 200 are in phase, and when the first active path 100 is turned on, a medium-high gain gear can be achieved, and when the second active path 200 is turned on, a medium-low gain gear can be achieved, thereby ensuring the phase continuity of the output signal at different gain gears.
[0081] Although the second active path 200 with a relatively low gain level can also achieve better linearity, the linearity of the active path still needs to be improved when achieving a low gain level. Figure 4 As shown, the low noise amplifier may also include a passive path 300, the first active path 100, the second active path 200 and the passive path 300 share the input circuit 10 and the output circuit 20; the first active path 100, the second active path 200 and the passive path 300 are turned on in a time-sharing manner, and the input signal is amplified in the first active path 100, or in the second active path 200, or in the passive path 300 after passing through the input circuit 10, and then outputted through the output circuit 200.
[0082] In this embodiment, the gain range of the passive path 300 and the gain range of the second active path 200 at least partially overlap. Specifically, the passive path 300 can achieve a low gain gear when it is turned on, and the passive path 300 has a higher linearity when achieving the low gain gear.
[0083] In this way, when there is a requirement for phase continuity, the first active path 100 can be used to achieve a medium-high gain gear, and the second active path 200 can be used to achieve a medium-low gain gear, which can ensure phase continuity while having better linearity.
[0084] In the absence of phase continuity requirements, the first active path 100 can be used to achieve medium and high gain gears, and the passive path 300 can be used to achieve low gain gears. Alternatively, the first active path 100 can be used to achieve medium and high gain gears, and the second active path 200 can be used to achieve medium and low gain gears while maintaining better linearity, and the passive path 300 can be used to achieve low gain gears, and the linearity in the low gain gear is higher.
[0085] Optional, such as Figure 4 As shown, the passive path 300 includes an input circuit 10, a fifth switch K5, a second attenuation circuit 310, a sixth capacitor C6 and an output circuit 20 connected in sequence along the signal transmission direction;
[0086] Among them, the first end of the fifth switch K5 is electrically connected to the second end of the first capacitor C1 in the input circuit 10, the second end of the fifth switch K5 is electrically connected to the first end of the second attenuation circuit 310, the second end of the second attenuation circuit 310 is electrically connected to the first end of the sixth capacitor C6, and the second end of the sixth capacitor C6 is electrically connected to the first end of the output circuit 20.
[0087] It is understandable that if Figure 4 As shown, when the fifth switch K5 is closed, the passive path 300 is turned on; when the fifth switch K5 is turned off, the passive path 300 is turned off. When the passive path 300 is turned on, the signal inputted from the signal input terminal RFIN passes through the input circuit 10, and then sequentially passes through the fifth switch K5, the second attenuation circuit 310 and the sixth capacitor C6 before being transmitted to the output circuit 20, and finally transmitted to the signal output terminal RFOUT by the output circuit 20. In this way, the signal outputted from the signal output terminal RFOUT is in phase with the signal inputted from the signal input terminal RFIN.
[0088] like Figure 4As shown, the gain of the passive path 300 can be adjusted by adjusting the second attenuation circuit 310. Optionally, the second attenuation circuit 310 adopts a π-type structure, that is, the second attenuation circuit 320 includes a resistor R21, a resistor R22, and a resistor R23, wherein the resistor R21 is located in the passive path 300, one end of the resistor R21 is grounded through the resistor R22, and the other end of the resistor R21 is grounded through the resistor R23, but the circuit structure of the second attenuation circuit 310 is not limited to the π-type structure, and can also be a T-type structure, a resistor network structure, etc.
[0089] Optional, such as Figure 4 As shown, the low noise amplifier also includes a sixth switch K6, which is located between the second end of the first capacitor C1 in the input circuit 10 and the first end of the fifth switch K5, and between the second end of the first capacitor C1 in the input circuit 10 and the first end of the second switch K2, that is, the sixth switch 6 serves as a common switch for the second active path 200 and the passive path 300, that is, when the fifth switch unit 30 is closed, the second active path 200 or the passive path 300 may be turned on, and when the fifth switch unit 30 is turned off, both the second active path 200 and the passive path 300 are turned off.
[0090] Optional, such as Figure 4 As shown, the common end connected to the first inductor L1 and the first capacitor C1 is grounded through the third attenuation circuit 11. In the low noise amplifier, the attenuation circuit is provided at the signal input end to adjust the amplitude of the input signal to adapt it to the processing range of the low noise amplifier, ensuring that the signal will not be distorted or damage the amplifier due to excessive amplitude during the amplification process; although the attenuation circuit itself will increase a certain amount of noise, in some cases, it can optimize the overall noise performance of the amplifier by adjusting the signal amplitude, and the attenuation circuit can also help improve the linearity of the amplifier.
[0091] Another option, such as Figure 5 As shown, the first attenuation circuit 210 in the second active path 200 and / or the second attenuation circuit 310 in the passive path 300 can also be multiplexed as the attenuation circuit of the signal input end, that is, there is no need Figure 4 The third attenuation circuit 11 in.
[0092] It can be understood that when the first attenuation circuit 210 in the multiplexed second active path 200 is the attenuation circuit of the signal input end, the sixth switch K6 and the second switch K2 are closed; when the second attenuation circuit 310 in the multiplexed passive path 300 is the attenuation circuit of the signal input end, the sixth switch K6 and the second switch K2 are closed; when the first attenuation circuit 210 in the second active path 200 and the second attenuation circuit 310 in the passive path 300 are multiplexed as the attenuation circuit of the signal input end as a whole, the sixth switch K6, the second switch K2 and the fifth switch K5 are all closed.
[0093] It can be understood that when the first attenuation circuit 210 in the second active path 200 and / or the second attenuation circuit 310 in the passive path 300 are multiplexed as the attenuation circuit of the signal input end, the third attenuation circuit 11 at the signal input end can be removed, which can reduce the layout area of the low noise amplifier, reduce power consumption and cost; and, the first attenuation circuit 210 in the second active path 200 and / or the second attenuation circuit 310 in the passive path 300 are multiplexed as the attenuation circuit of the signal input end, which can optimize the linearity of the medium gain gear and reduce the parasitic effects of the third attenuation circuit 11 at the signal input end.
[0094] Based on any of the above embodiments, optionally, Figure 4 and Figure 5 As shown, the output circuit 20 includes a seventh capacitor C7, an eighth capacitor C8 and a fourth attenuation circuit 21, the first end of the seventh capacitor C7 is the first end of the output circuit 20, the second end of the seventh capacitor C7 is grounded through the eighth capacitor C8, the second end of the seventh capacitor C7 is also electrically connected to the first end of the fourth attenuation circuit 21, and the second end of the fourth attenuation circuit 21 is the second end of the output circuit 20, that is, the signal output end RFOUT.
[0095] The gains of the first active path 100, the second active path 200 and the passive path 300 can also be adjusted by adjusting the fourth attenuation circuit 21. Optionally, the fourth attenuation circuit 21 adopts a π-type structure, that is, the fourth attenuation circuit 21 includes a resistor R31, a resistor R32 and a resistor R33, wherein the resistor R31 is located in the output circuit 20, one end of the resistor R31 is grounded through the resistor R32, and the other end of the resistor R31 is grounded through the resistor R33, but the circuit structure of the fourth attenuation circuit 21 is not limited to the π-type structure, and can also be a T-type structure, a resistor network structure, etc.
[0096] Accordingly, an embodiment of the present application further provides a radio frequency module, including the low noise amplifier provided by any of the above embodiments. Since the circuit structure of the low noise amplifier has been described in detail in the above embodiments, it will not be repeated here.
[0097] The various parts in this manual are described in a combination of parallel and progressive ways. Each part focuses on the differences from other parts, and the same or similar parts between the various parts can be referenced to each other.
[0098] With respect to the above description of the disclosed embodiments, the features described in the embodiments in this specification may be replaced or combined with each other, so that professionals in the field can implement or use the present application. Various modifications to these embodiments will be apparent to professionals in the field, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A low noise amplifier, characterized in that: comprising a first active path and a second active path, wherein the first active path and the second active path share an input circuit and an output circuit; The first active path and the second active path are turned on in a time-sharing manner, and the input signal is amplified in the first active path or in the second active path after passing through the input circuit, and then outputted through the output circuit; The gain range of the first active path is at least partially greater than the gain range of the second active path; The signal output by the first active path and the signal output by the second active path are in phase.
2. The low noise amplifier according to claim 1, characterized in that: The first active path includes the input circuit, the first amplifier tube, the first switch, the second amplifier tube and the output circuit connected in sequence along the signal transmission direction; The input circuit includes a first inductor and a first capacitor, wherein the first end of the first inductor is a signal input end, the second end of the first inductor is electrically connected to the first end of the first capacitor, and the second end of the first capacitor is electrically connected to the control end of the first amplifier tube; The control end of the first amplifier tube is also connected to the first bias voltage through the first resistor; the first end of the first amplifier tube is electrically connected to the first end of the first switch; the second end of the first amplifier tube is grounded through the feedback circuit; the first amplifier tube is used to invert and amplify the signal; The control end of the second amplifier tube is connected to the second bias voltage through the second resistor and is grounded through the second capacitor; the first end of the second amplifier tube is connected to the power supply voltage through the second inductor and is electrically connected to the first end of the output circuit; the second end of the second amplifier tube is electrically connected to the second end of the first switch; the second amplifier tube is used to amplify the signal in phase; the second end of the output circuit is a signal output end; The first inductor, the first capacitor, the first resistor, the first amplifier tube and the feedback circuit constitute an input matching network of the first active path.
3. The low noise amplifier according to claim 2, characterized in that: The second active path includes the input circuit, the second switch, the first attenuation circuit, the third capacitor, the third amplifier tube, the third switch, the fourth amplifier tube and the output circuit which are sequentially connected along the signal transmission direction; The first end of the second switch is electrically connected to the second end of the first capacitor in the input circuit, the second end of the second switch is electrically connected to the first end of the first attenuation circuit, the second end of the first attenuation circuit is electrically connected to the first end of the third capacitor, and the second end of the third capacitor is electrically connected to the control end of the third amplifier tube; The control end of the third amplifier tube is also connected to the third bias voltage through the third resistor; the first end of the third amplifier tube is electrically connected to the first end of the third switch; the second end of the third amplifier tube is electrically connected to the end of the feedback circuit away from the ground through the fourth switch; the third amplifier tube is used to invert the signal; The control end of the fourth amplifier tube is connected to the fourth bias voltage through the fourth resistor and is grounded through the fourth capacitor; the first end of the fourth amplifier tube is connected to the power supply voltage through the second inductor and is electrically connected to the first end of the output circuit; the second end of the second amplifier tube is electrically connected to the second end of the third switch; the second amplifier tube is used to amplify the signal in phase; The first inductor, the first capacitor, the third capacitor, the third resistor, the third amplifier tube and the feedback circuit constitute an input matching network of the second active path.
4. The low noise amplifier according to claim 3, characterized in that: A fifth capacitor is electrically connected between the control end and the second end of the third amplifier tube; The first inductor, the first capacitor, the third capacitor, the third resistor, the fifth capacitor, the third amplifier tube and the feedback circuit constitute an input matching network of the second active path.
5. The low noise amplifier according to claim 3, characterized in that: The second switch tube is multiplexed as the fourth switch tube, the second resistor is multiplexed as the fourth resistor, the second capacitor is multiplexed as the fourth capacitor, and the second bias voltage is multiplexed as the fourth bias voltage.
6. The low noise amplifier according to any one of claims 3 to 5, characterized in that: The low noise amplifier further comprises a passive path, wherein the first active path, the second active path and the passive path share the input circuit and the output circuit; The first active path, the second active path and the passive path are turned on in a time-sharing manner, and the input signal is amplified in the first active path, or in the second active path, or in the passive path after passing through the input circuit, and then outputted through the output circuit; The gain range of the passive path and the gain range of the second active path at least partially overlap.
7. The low noise amplifier according to claim 6, characterized in that: The passive path includes the input circuit, the fifth switch, the second attenuation circuit, the sixth capacitor and the output circuit connected in sequence along the signal transmission direction; The first end of the fifth switch is electrically connected to the second end of the first capacitor in the input circuit, the second end of the fifth switch is electrically connected to the first end of the second attenuation circuit, the second end of the second attenuation circuit is electrically connected to the first end of the sixth capacitor, and the second end of the sixth capacitor is connected to the first end of the output circuit.
8. The low noise amplifier according to claim 7, characterized in that: A common end of the first inductor and the first capacitor is grounded through a third attenuation circuit.
9. The low noise amplifier according to claim 7, characterized in that: The first attenuation circuit in the second active path and / or the second attenuation circuit in the passive path are multiplexed as an attenuation circuit at a signal input end.
10. A radio frequency module, characterized in that: A low noise amplifier comprising the low noise amplifier according to any one of claims 1 to 9.