Low noise amplifier and related device

Abstract

The invention relates to the field of radio frequency, and particularly discloses a low-noise amplifier and related equipment. The low-noise amplifier comprises a first switching circuit, a second switching circuit, a first common-source amplifying circuit, a second common-source amplifying circuit, a common-gate amplifying circuit, a first series capacitor array, a second series capacitor array, a switch K1 and a grounding switch K2. According to the embodiment of the invention, for the multi-input LNA, by multiplexing the common-gate amplification circuit, the number of common-gate amplification circuits in the LNA is reduced, the layout area of the circuit is reduced, and the hardware cost is reduced.

Description

Technical Field

[0001] The present application relates to the field of radio frequency, and in particular to a low noise amplifier and related equipment. Background Art

[0002] In the design of low noise amplifier (LNA) based on silicon on insulator (SOI) technology, the source degenerate inductor type common source amplifier has the advantages of low noise figure, high gain, good linearity, etc., and can use its own capacitance to achieve input impedance matching. In order to eliminate the influence of its Miller effect and limited output impedance on the performance of LNA, and to provide good reverse isolation performance, LNA usually adopts a common source and common gate (Cascode) structure.

[0003] For multi-input LNA, when the frequencies of the input RF signals are close, in order to achieve better signal amplification effect, multiple common-source amplifier circuits and multiple common-gate amplifier circuits are generally used to form multiple common-source and common-gate structures to amplify RF signals of different frequencies respectively. However, since there are multiple common-source amplifier circuits and common-gate amplifier circuits, the layout area of ​​the circuit is increased, thereby increasing the hardware cost. Summary of the invention

[0004] The embodiments of the present application provide a low noise amplifier and related devices. The use of the embodiments of the invention is beneficial to reducing the layout area of ​​the circuit and lowering the hardware cost.

[0005] In a first aspect, an embodiment of the present application provides an LNA, comprising: a first switch circuit, a second switch circuit, a first common-source amplifier circuit, a second common-source amplifier circuit, a common-gate amplifier circuit, a first series capacitor array, a second series capacitor array, a matching switch K1, and a ground switch K2.

[0006] The first end of the first switch circuit is coupled to the first input end of the LNA, the second end of the first switch circuit is coupled to the input end of the first common-source amplifier circuit, the first end of the second switch circuit is coupled to the second input end of the LNA, and the second end of the second switch circuit is coupled to the input end of the second common-source amplifier circuit; the output end of the first common-source amplifier circuit and the output end of the second common-source amplifier circuit are both coupled to the input end of the common-gate amplifier circuit; the output end of the common-gate amplifier circuit is coupled to the power supply V DD The first switch circuit and the second switch circuit are coupled to the power supply V through the second series capacitor array. DD The first series capacitor array is coupled to the output end of the LNA; the second series capacitor array is coupled to the power supply V through the matching switch K1. DDand a first series capacitor array, wherein a first end of the matching switch K1 is coupled to a first end of the first series capacitor array, and a second end of the matching switch K1 is coupled to a first end of the second series capacitor array; a first end of the grounding switch K2 is coupled between the first switch circuit, the second switch circuit and a second end of the second series capacitor array, wherein a second end of the grounding switch K2 is grounded, and a second end of the first series capacitor array is coupled to an output end of the LNA.

[0007] The structure of a two-input LNA is described above. Based on the above circuit structure, a multi-input LNA can be obtained.

[0008] For a multi-input LNA, by multiplexing the common-gate amplifier circuit, the number of the common-gate amplifier circuits in the LNA is reduced compared to the prior art, which is beneficial to reducing the layout area of ​​the circuit and reducing the hardware cost.

[0009] In combination with the first aspect, in a possible implementation, if a first RF signal is input from a first end of a first switch circuit and the LNA operates in a first state, the first end and the second end of the first switch circuit are turned on, the matching switch K1 is controlled to be disconnected and the grounding switch K2 is controlled to be closed, and the common-gate amplifier circuit and the first common-source amplifier circuit are used to amplify the first RF signal; the amplified first RF signal is matched to the output impedance of the LNA through a first series capacitor array.

[0010] In combination with the first aspect, in a possible implementation, if the second RF signal is input from the first end of the first switch circuit and the LNA is operating in the first state, the first end and the second end of the first switch circuit are controlled to be turned on, the matching switch K1 is controlled to be closed and the grounding switch K2 is controlled to be closed, and the common-gate amplifier circuit and the first common-source amplifier circuit are used to amplify the second RF signal; the amplified second RF signal matches the output impedance of the LNA through the first series capacitor array and the second series capacitor array.

[0011] The frequency of the first RF signal is higher than the frequency of the second RF signal. In one example, the first RF signal is a high-frequency RF signal, and the second RF signal is a low-frequency RF signal. The frequency difference between the first RF signal and the second RF signal is not less than 200 MHz.

[0012] It should be noted that the low-frequency RF signal here refers to a signal with a frequency lower than the first frequency threshold, and the high-frequency RF signal refers to a signal with a frequency higher than the second frequency threshold. Optionally, the first frequency threshold is 2.1 GHz or other values, and the second frequency threshold is 2.3 GHz or other values.

[0013] In combination with the first aspect, in a possible implementation, if the RF signal is input from the first end of the first switch circuit and the LNA is operating in the second state, the first end and the third end of the first switch circuit are controlled to be turned on, the matching switch K1 is controlled to be closed and the grounding switch K2 is controlled to be opened; the RF signal matches the input impedance and output impedance of the LNA through the first series capacitor array and the second series capacitor array.

[0014] In combination with the first aspect, in a possible implementation, when the LNA operates in the second state, the power supply V DD Power off.

[0015] In one example, the first state is an active gain state, and the second state is a passive gain state. The active gain state means that the LNA has a power source involved in adjusting the gain of the RF signal, such as the power source V DD Power on, passive gain state means that the LNA does not have power involved in adjusting the gain of the RF signal, that is, the power supply V DD Power off.

[0016] In combination with the first aspect, in a possible implementation, the LNA further includes an inductive circuit and an attenuator. The inductive circuit is coupled to the output end of the common-gate amplifier circuit, the first end of the first series capacitor array, and the first end of the matching switch K1 and the power supply V DD The input end of the attenuator is coupled to the second end of the first series capacitor array, and the output end of the attenuator is coupled to the output end of the LNA.

[0017] When the first RF signal is input from the first end of the first switch circuit and the LNA is working in the first state, the amplified first RF signal matches the output impedance of the LNA through the inductive circuit and the first series capacitor array; when the second RF signal is input from the first end of the first switch circuit and the LNA is working in the first state, the amplified second RF signal matches the output impedance of the LNA through the inductive circuit, the first series capacitor array and the second series capacitor array. The attenuator is used to adjust the power of the RF signal output by the common-gate amplifier circuit.

[0018] When the RF signal is input from the first end of the first switch circuit and the LNA operates in the second state, the RF signal matches the input impedance and output impedance of the LNA through the inductive circuit, the first series capacitor array and the second series capacitor array. It should be understood that the RF signal here is a high-frequency RF signal or a low-frequency RF signal. The attenuator is used to adjust the power of the RF signal input from the first end of the first switch circuit.

[0019] By introducing the inductive circuit, the RF signal can better match the input impedance and output impedance of the LNA, and the RF signal can be prevented from leaking from the common gate output node to the power supply V DD, resulting in energy leakage. By introducing an attenuator, the ability of LNA to adjust gain can be improved.

[0020] In combination with the first aspect, in a possible implementation, the LNA further includes a first isolation network and a second isolation network, the third end of the first switch circuit is coupled to the second end of the second series capacitor array through the first isolation network, and the third end of the second switch circuit is coupled to the second end of the second series capacitor array through the second isolation network; when the RF signal is input from the first end of the first switch circuit and the LNA operates in the first state, the first isolation network is disconnected; when the RF signal is input from the first end of the first switch circuit and the LNA operates in the second state, the first isolation network is turned on.

[0021] By introducing an isolation network, the reverse isolation of the LNA can be improved, that is, the influence of the output signal of the LNA on the input signal can be reduced.

[0022] In combination with the first aspect, in a possible implementation, the first isolation network includes a third switch circuit, a fourth switch circuit, and a fifth switch circuit; wherein a second end of the fifth switch circuit is grounded, a first end of the third switch circuit is coupled to a first end of the first isolation network, and a second end of the fourth switch circuit is coupled to a second end of the first isolation network;

[0023] When the first end and the second end of the third switch circuit are turned on, the first end and the second end of the fourth switch circuit are turned on, and the first end and the second end of the fifth switch circuit are turned off, the first end and the second end of the first isolation network are turned on; on the premise that the first end and the second end of the fifth switch circuit are turned off, if the first end and the second end of the third switch circuit are turned off or the first end and the second end of the fourth switch circuit are turned off, the first end and the second end of the first isolation network are turned off; when the first end and the second end of the fifth switch circuit are turned on, if the first end and the second end of the third switch circuit are turned off or the first end and the second end of the fourth switch circuit are turned off, the first end and the second end of the first isolation network are turned off.

[0024] Immediately, the first end and the second end of the first isolation network are connected, that is, the first isolation network is turned on; the first end and the second end of the first isolation network are disconnected, that is, the first isolation network is disconnected.

[0025] In combination with the first aspect, in a possible implementation, the first common-source amplifier circuit includes multiple first amplifier circuits and a first switch array, the input ends of the multiple first amplifier circuits are the input ends of the common-source amplifier circuit, the output end of each first amplifier circuit in the multiple first amplifier circuits is coupled to the first end of a switch in the first switch array, wherein the second end of the switch in the first switch array is the output end of the common-source amplifier circuit, and the opening and closing of the switches in the first switch array are controlled to adjust the gain of the first common-source amplifier circuit.

[0026] Optionally, the structure of the second common-source amplifier circuit is the same as or different from the structure of the first common-source amplifier circuit.

[0027] In combination with the first aspect, in a possible implementation, the common-gate amplifier circuit includes a plurality of second amplifier circuits and a second switch array, the input ends of the plurality of second amplifier circuits are the input ends of the common-gate amplifier circuit, the output ends of the plurality of second amplifier circuits are the output ends of the common-gate amplifier circuit, the control end of each of the plurality of second amplifier circuits is coupled to a first end of a switch in the second switch array, and the other end of the switch is coupled to a power supply V DD coupling;

[0028] The working state of the second amplifier circuit is controlled by controlling the opening and closing of the switches in the second switch array to adjust the gain of the common-gate amplifier circuit.

[0029] In combination with the first aspect, in a possible implementation manner, the first series capacitor array includes a plurality of capacitors and a plurality of switches, and the plurality of switches correspond to the plurality of capacitors;

[0030] The first end of the multiple switches is the first end of the first series capacitor array, the second end of each switch in the multiple switches is coupled to the first end of the capacitor corresponding to the switch, and the second end of the multiple capacitors is the second end of the first series capacitor array; the opening and closing of the switches in the first series capacitor array are controlled to adjust the capacitance of the first series capacitor array.

[0031] By adjusting the capacitance of the first series array, the input radio frequency signal can be matched with the input impedance or output impedance of the LNA.

[0032] In a second aspect, an embodiment of the present application provides another LNA, which includes a switch circuit, an amplifier circuit, a first series capacitor array, a second series capacitor array, a matching switch K1 and a ground switch K2; wherein a first end of the switch circuit is coupled to an input end of the LNA, a second end of the switch circuit is coupled to an input end of the amplifier circuit, and a power supply V DD coupled to the output end of the amplifier circuit, the input end of the first series capacitor array and the first end of the matching switch K1 are both coupled to the output end of the amplifier circuit, the third end of the switch circuit and the first end of the grounding switch K2 are coupled to the first end of the second series capacitor array, the second end of the grounding switch K2 is grounded, the second end of the second series capacitor array is coupled to the second end of the matching switch K1, and the second end of the first series capacitor array is coupled to the output end of the LNA;

[0033] When the LNA operates in the first state, the first end of the switch circuit is connected to the second end of the switch circuit, and when the input RF signal is the first RF signal, the matching switch K1 is disconnected, the ground switch K2 is closed, and the amplifier circuit is used to amplify the first RF signal; the amplified first RF signal matches the output impedance of the LNA through the first series capacitor array; when the input RF signal is the second RF signal, the matching switch K1 and the ground switch K2 are both closed, and the amplifier circuit is used to amplify the first RF signal, and the amplified first RF signal matches the output impedance of the LNA through the first series capacitor array and the second series capacitor array.

[0034] The frequency of the first RF signal is higher than the frequency of the second RF signal. In one example, the first RF signal is a high-frequency RF signal, and the second RF signal is a low-frequency RF signal. The frequency difference between the first RF signal and the second RF signal is not less than 200 MHz.

[0035] It should be noted that the low-frequency RF signal here refers to a signal with a frequency lower than the first frequency threshold, and the high-frequency RF signal refers to a signal with a frequency higher than the second frequency threshold. Optionally, the first frequency threshold is 2.1 GHz or other values, and the second frequency threshold is 2.3 GHz or other values.

[0036] In combination with the second aspect, in a possible implementation, when the LNA operates in the second state, the first end of the switch circuit is connected to the second end of the switch circuit, and the matching switch K1 and the grounding switch K2 are turned on; the input RF signal matches the input impedance and output impedance of the LNA through the first series capacitor array and the second series capacitor array.

[0037] In combination with the second aspect, in a possible implementation, when the LNA operates in the second state, the power supply V DD Power off.

[0038] In one example, the first state is an active gain state, and the second state is a passive gain state. The active gain state means that the LNA has a power source involved in adjusting the gain of the RF signal, such as the power source V DD Power on, passive gain state means that the LNA does not have power involved in adjusting the gain of the RF signal, that is, the power supply V DD Power off.

[0039] In combination with the second aspect, in a possible implementation, the LNA further includes an inductive circuit and an attenuator. One end of the inductive circuit is coupled to the power supply VDD, and the other end is coupled to the output end of the common-gate amplifier circuit, the first end of the matching switch K1, and the first end of the first series capacitor array. The input end of the attenuator is coupled to the second end of the first series capacitor array, and the output end of the attenuator is coupled to the output end of the LNA.

[0040] The attenuator is used to adjust the power of the radio frequency signal output by the common-gate amplifier circuit, or to adjust the power of the radio frequency signal input from the first end of the switch circuit.

[0041] In combination with the second aspect, in a possible implementation, the LNA further includes an isolation network, and the third end of the switch circuit is coupled to the first end of the ground switch K2 through the isolation network; when the LNA operates in the first state, the isolation network is disconnected; when the LNA operates in the second state, the isolation network is turned on.

[0042] In combination with the second aspect, in a possible implementation, the isolation network includes a third switch circuit, a fourth switch circuit, and a fifth switch circuit; wherein a second end of the fifth switch circuit is grounded, a first end of the third switch circuit is coupled to a first end of the isolation network, and a second end of the fourth switch circuit is coupled to a second end of the isolation network;

[0043] When the first end and the second end of the third switch circuit are turned on, the first end and the second end of the fourth switch circuit are turned on, and the first end and the second end of the fifth switch circuit are turned off, the first end and the second end of the isolation network are turned on; on the premise that the first end and the second end of the fifth switch circuit are turned off, if the first end and the second end of the third switch circuit are turned off or the first end and the second end of the fourth switch circuit are turned off, the first end and the second end of the isolation network are turned off; when the first end and the second end of the fifth switch circuit are turned on, if the first end and the second end of the third switch circuit are turned off or the first end and the second end of the fourth switch circuit are turned off, the first end and the second end of the isolation network are turned off.

[0044] Immediately, the first end and the second end of the isolation network are connected, that is, the isolation network is turned on; the first end and the second end of the isolation network are disconnected, that is, the isolation network is disconnected.

[0045] In combination with the second aspect, in a possible implementation, the common source amplifier circuit includes multiple first amplifier circuits and a first switch array, the input ends of the multiple first amplifier circuits are the input ends of the common source amplifier circuit, the output end of each first amplifier circuit in the multiple first amplifier circuits is coupled to the first end of a switch in the first switch array, wherein the second end of the switch in the first switch array is the output end of the common source amplifier circuit, and the opening and closing of the switches in the first switch array are controlled to adjust the gain of the common source amplifier circuit.

[0046] In combination with the second aspect, in one possible implementation, the amplifier circuit includes a common-source amplifier circuit and a common-gate amplifier circuit, the input end of the common-source amplifier circuit is coupled to the input end of the amplifier circuit, the output end of the common-source amplifier circuit is coupled to the input end of the common-gate amplifier circuit, and the output end of the common-gate amplifier circuit is the output end of the amplifier circuit.

[0047] In conjunction with the second aspect, in a possible implementation, when the LNA has multiple inputs, that is, when the LNA is a multi-input LNA, there are multiple common-source amplifier circuits, there are multiple switch circuits, and the multiple common-source amplifier circuits correspond to the multiple switch circuits;

[0048] The first ends of the multiple switch circuits are coupled to the multiple input ends of the LNA, the second end of each switch circuit is coupled to the input end of the common-source amplifier circuit corresponding to the switch circuit, and the output ends of the multiple common-source amplifier circuits are coupled to the input end of the common-gate amplifier circuit; the third ends of the multiple switch circuits are coupled to the first end of the second series capacitor array.

[0049] In combination with the first aspect, in a possible implementation manner, the LNA further includes a plurality of isolation networks, and the third ends of the plurality of switch circuits are respectively coupled to the first end of the second series capacitor array through the plurality of isolation networks.

[0050] In combination with the second aspect, in a possible implementation, the common source amplifier circuit includes multiple first amplifier circuits and a switch array, the input ends of the multiple first amplifier circuits are the input ends of the common source amplifier circuit, the output end of each of the multiple first amplifier circuits is coupled to the first end of a switch of the switch array, wherein the second end of the switch of the switch array is the output end of the common source amplifier circuit, and the opening and closing of the switches in the switch array are controlled to adjust the gain of the common source amplifier circuit.

[0051] In combination with the second aspect, in a possible implementation, the common-gate amplifier circuit includes a plurality of second amplifier circuits and a second switch array, the input ends of the plurality of second amplifier circuits are the input ends of the common-gate amplifier circuit, the output ends of the plurality of second amplifier circuits are the output ends of the common-gate amplifier circuit, the control end of each of the plurality of second amplifier circuits is coupled to a first end of a switch in the second switch array, and the other end of the switch is coupled to a power supply V DD coupling; controlling the operating state of the second amplifier circuit by controlling the opening and closing of the switches in the second switch array to adjust the gain of the common-gate amplifier circuit.

[0052] In combination with the second aspect, in a possible implementation, the first series capacitor array includes multiple capacitors and multiple switches, and the multiple switches correspond to the multiple capacitors; the first end of the multiple switches is the first end of the first series capacitor array, the second end of each of the multiple switches is coupled to the first end of the capacitor corresponding to the switch, and the second end of the multiple capacitors is the second end of the first series capacitor array; the opening and closing of the switches in the first series capacitor array are controlled to adjust the capacitance of the first series capacitor array.

[0053] In a third aspect, an embodiment of the present application further provides a radio frequency front-end chip, which includes the LNA as described in the first aspect, the LNA as described in any possible implementation of the first aspect, the LNA as described in the second aspect, or the LNA as described in any possible implementation of the second aspect.

[0054] In one example, the RF front-end chip is a low noise amplifier power amplifier module integrated duplexer (LNA-Power Amplifier Module Integrated Duplexer, LPAMiD).

[0055] In a fourth aspect, an embodiment of the present application provides an electronic device, comprising the LNA as described in the first aspect, the LNA as described in any possible implementation manner in the first aspect, the LNA as described in the second aspect, or the LNA as described in any possible implementation manner in the second aspect, or the RF front-end chip as described in the third aspect.

[0056] These and other aspects of the present application will become more clearly understood in the description of the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] 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.

[0058] Figure 1 A schematic diagram of the architecture of an LPAMiD provided in an embodiment of the present application;

[0059] Figure 2 A schematic diagram of the structure of an LNA provided in an embodiment of the present application;

[0060] Figure 3 A schematic diagram of the structure of an isolated network provided in an embodiment of the present application;

[0061] Figure 4 A schematic diagram of the structure of a common source amplifier circuit provided in an embodiment of the present application;

[0062] Figure 5 A schematic diagram of the structure of a common-gate amplifier circuit provided in an embodiment of the present application;

[0063] Figure 6a A schematic diagram of the structure of a switched capacitor array provided in an embodiment of the present application;

[0064] Figure 6bA schematic diagram of the structure of another LNA provided in an embodiment of the present application;

[0065] Figure 7a is a schematic diagram of the structure of an LNA;

[0066] Figure 7b is a schematic diagram of the structure of another LNA;

[0067] Figure 8 is a schematic diagram of the structure of another LNA;

[0068] Fig. 9 A schematic diagram of the structure of another LNA provided in an embodiment of the present application. DETAILED DESCRIPTION

[0069] The embodiments of the present application are described below in conjunction with the accompanying drawings.

[0070] See also Figure 1 , Figure 1 A schematic diagram of the architecture of an LPAMiD provided in an embodiment of the present application. Figure 1 As shown, the LPAMiD includes: at least one high band power amplifier (HBPA), at least one intermediate frequency power amplifier (MBPA), an X-band antenna switch (XSW) module, a middle high band filter (MHB filter) module, an antenna switch module (ASM), at least one LNA circuit and a multi-pole multi-throw (NpoleN Throw, NPNT) switch.

[0071] Among them, the first RF signal is input from the input end HB_IN of at least one HBPA, the second RF signal is input from the input end MB_IN of at least one MBPA, and at least one HBPA and at least one MBPA are coupled to the medium and high frequency filter module through the XSW module; when there are multiple HBPAs, multiple HBPAs are cascaded, the first RF signal is input from the input end of the first HBPA, that is, the input end of the first HBPA is coupled to the input end HB_IN of at least one HBPA, and the output end of the last HBPA is coupled to the XSW module; similarly, when there are multiple MBPAs, multiple MBPAs are cascaded, the second RF signal is input from the input end of the first MBPA, that is, the input end of the first MBPA is coupled to the input end MB_IN of at least one MBPA, and the output end of the last MBPA is coupled to the XSW module, the medium and high frequency filter module is coupled to the antenna through the ASM module, the input end of at least one LNA is coupled to the medium and high frequency filter module, and the output end of at least one LNA is coupled to the NPNT switch.

[0072] The MBPA is used to amplify the input second RF signal. When there are multiple MBPAs, the multiple MBPAs are used to perform multi-stage amplification on the input second RF signal. The HBPA is used to amplify the input first RF signal. When there are multiple HBPAs, the multiple HPBAs are used to perform multi-stage amplification on the input first RF signal.

[0073] The medium and high frequency filter module includes a variety of filters, such as bandpass filters, etc. Optionally, the medium and high frequency filter module also includes a duplexer and various forms of multiplexers. The signal output by the MBPA and the signal output by the HBPA are input into the corresponding filter or duplexer in the medium and high frequency filter module through the XSW module for filtering. Among them, the XSW module can be regarded as a frequency selection switch, which is used to select the corresponding filter for the signal output by the MBPA and the signal output by the HBPA. The filtered signal is output to the antenna through the ASM module and then transmitted through the antenna. The ASM module can also be regarded as a selection switch, which is used to select the filter and select the transmitting antenna for the filtered signal.

[0074] For the RF signal received by the antenna, the ASM module is controlled to select a suitable filter for filtering the RF signal. The filtered signal is input to the LNA through the input terminal RF_IN of the LNA. After the LNA processes the input signal, it is input to the NPNT switch through the output terminal RF_OUT and then output through the NPNT switch. In an example, the antenna here includes a medium-high frequency antenna, such as Figure 1 MHB_ANT1 and MHB_ANT2 in.

[0075] Optionally, the LNA is a single-input single-output device or a multiple-input single-output device. Figure 3 As shown, LNA has three inputs and one output. LPAMiD includes four LNAs. The signals output by the four LNAs are all input to the 4P5T switch. The 4P5T switch is used to control the signals output by the four LNAs to be output from any four of the five output ports of the 4P5T switch. For example, the 4P5T switch can control the signal output by LNA1 to be output from LNA_OUT1, and can also control the signal output by LNA1 to be output from LNA_OUT4.

[0076] Below Figure 1 The LNA in FIG. 1 is described in detail.

[0077] See also Figure 2 , Figure 2 A schematic diagram of an LNA structure provided in an embodiment of the present application. Figure 2 As shown, the LNA includes a first switch circuit, a second switch circuit, a first common-source amplifier circuit, a second common-source amplifier circuit, a common-gate amplifier circuit, a first series capacitor array, a second series capacitor array, a matching switch K1 and a grounding switch K2.

[0078] The first end of the first switch circuit is coupled to the first input end RF_IN1 of the LNA, the second end of the first switch circuit is coupled to the input end of the first common-source amplifier circuit, the first end of the second switch circuit is coupled to the second input end RF_IN2 of the LNA, and the second end of the second switch circuit is coupled to the input end of the second common-source amplifier circuit; the output end of the first common-source amplifier circuit and the output end of the second common-source amplifier circuit are both coupled to the input end of the common-gate amplifier circuit; the output end of the common-gate amplifier circuit is coupled to the power supply V DD The first switch circuit and the second switch circuit are coupled to the power supply V through the second series capacitor array. DD The first series capacitor array is coupled to the output end of the LNA; the second series capacitor array is coupled to the power supply V through the matching switch K1. DD and a first series capacitor array, wherein a first end of the matching switch K1 is coupled to a first end of the first series capacitor array, and a second end of the matching switch K1 is coupled to a first end of the second series capacitor array; a first end of the grounding switch K2 is coupled between the first switch circuit, the second switch circuit and a second end of the second series capacitor array, wherein a second end of the grounding switch K2 is grounded, and a second end of the first series capacitor array is coupled to an output end RF_OUT of the LNA.

[0079] In other words, the first end of the first switch circuit is coupled to the first input end RF_IN1 of the LNA, the first end of the second switch is coupled to the second input end RF_IN2 of the LNA, the second end of the first switch circuit and the second end of the second switch circuit are respectively coupled to the input end of the first common-source amplifier circuit and the input end of the second common-source amplifier circuit, the third end of the first switch circuit and the third end of the second switch circuit are both coupled to the second end of the second series capacitor array, the output end of the first common-source amplifier circuit and the output end of the second common-source amplifier circuit are both coupled to the input end of the common-gate amplifier circuit, the output end of the common-gate amplifier circuit is coupled to the first end of the first series capacitor array, and the first end of the first series capacitor array is coupled to the power supply V DD , a first end of the matching switch K1 is coupled to a first end of the first series capacitor array, a second end of the matching switch K1 is coupled to a first end of the second series capacitor array, a first end of the grounding switch K2 is coupled to a second end of the second series capacitor array, a second end of the grounding switch K2 is grounded, and a second end of the first series capacitor array is coupled to an output end RF_OUT of the LNA.

[0080] For a multi-input LNA, by multiplexing the common-gate amplifier circuit, the number of the common-gate amplifier circuits in the LNA is reduced compared to the prior art, which is beneficial to reducing the layout area of ​​the circuit and reducing the hardware cost.

[0081] In a possible implementation, if the first RF signal is input from the first end of the first switch circuit and the LNA operates in the first state, the first end and the second end of the first switch circuit are controlled to be turned on, the switch K1 is controlled to be turned off and the switch K2 is controlled to be turned on, and the common-gate amplifier circuit and the first common-source amplifier circuit are used to amplify the first RF signal; the amplified first RF signal is matched to the output impedance of the LNA through the first series capacitor array.

[0082] If the second radio frequency signal is input from the first end of the first switch circuit and the LNA is operating in the first state, the first end and the second end of the first switch circuit are controlled to be turned on, the switch K1 is controlled to be closed and the switch K2 is controlled to be closed, and the common-gate amplifier circuit and the first common-source amplifier circuit are used to amplify the second radio frequency signal; the amplified second radio frequency signal is matched to the output impedance of the LNA through the first series capacitor array and the second series capacitor array.

[0083] The frequency of the first RF signal is higher than the frequency of the second RF signal. In one example, the first RF signal is a high-frequency RF signal, and the second RF signal is a low-frequency RF signal. The frequency difference between the first RF signal and the second RF signal is not less than 200 MHz.

[0084] It should be noted that the low-frequency RF signal here refers to a signal with a frequency lower than the first frequency threshold, and the high-frequency RF signal refers to a signal with a frequency higher than the second frequency threshold. Optionally, the first frequency threshold is 2.1 GHz or other values, and the second frequency threshold is 2.3 GHz or other values.

[0085] In a possible implementation, if the RF signal is input from the first end of the first switch circuit and the LNA is operating in the second state, the first end and the third end of the first switch circuit are controlled to be turned on, the switch K1 is controlled to be closed and the switch K2 is controlled to be opened; the RF signal input from the first end of the first switch circuit matches the input impedance and output impedance of the LNA through the first series capacitor array and the second series capacitor array.

[0086] In one possible implementation, when the LNA operates in the second state, the power supply V DD Power off so that the LNA can operate in the second state.

[0087] In one example, the first state is an active gain state, and the second state is a passive gain state. The active gain state means that the LNA has a power source involved in adjusting the gain of the RF signal, such as the power source V DD Power on, passive gain state means that the LNA does not have power involved in adjusting the gain of the RF signal, that is, the power supply V DD Power off.

[0088] In one possible implementation, Figure 2 The LNA shown also includes an inductive circuit and an attenuator. One end of the inductive circuit is coupled to a power supply V DD The other end of the inductive circuit is coupled to the output end of the common-gate amplifier circuit, the first end of the matching switch K1 and the first end of the first series capacitor array; the second end of the first series capacitor array is coupled to the input end of the attenuator, and the output end of the attenuator is coupled to the output end of the LNA.

[0089] When the first RF signal is input from the first end of the first switch circuit and the LNA is working in the first state, the amplified first RF signal matches the output impedance of the LNA through the inductive circuit and the first series capacitor array; when the second RF signal is input from the first end of the first switch circuit and the LNA is working in the first state, the amplified second RF signal matches the output impedance of the LNA through the inductive circuit, the first series capacitor array and the second series capacitor array. The attenuator is used to adjust the power of the RF signal output by the common-gate amplifier circuit.

[0090] When the RF signal is input from the first end of the first switch circuit and the LNA operates in the second state, the RF signal matches the input impedance and output impedance of the LNA through the inductive circuit, the first series capacitor array and the second series capacitor array. It should be understood that the RF signal here is a high-frequency RF signal or a low-frequency RF signal. The attenuator is used to adjust the power of the RF signal input from the first end of the first switch circuit.

[0091] Optionally, the inductive circuit is implemented based on an inductor, or based on a PMOS current mirror. Optionally, the inductor here is an inductor with a fixed inductance, or an inductor with an adjustable inductance.

[0092] By introducing the inductive circuit, the RF signal can better match the input impedance and output impedance of the LNA, and the RF signal can be prevented from leaking from the common gate output node to the power supply V DD , resulting in energy leakage. By introducing an attenuator, the ability of LNA to adjust gain can be improved.

[0093] Optional, such as Figure 2 As shown, the LNA further includes a first input matching circuit and a second input matching circuit, the first end of the first switch circuit is coupled to the first input end of the LNA through the first input matching circuit, and the first end of the second switch circuit is coupled to the second input end of the LNA through the second input matching circuit. By introducing the first input matching circuit and the second input matching circuit, the input RF signal is matched with the input impedance of the LNA.

[0094] When the LNA works in the passive gain state, the input matching circuit will affect the matching pole, input impedance and output impedance of the Passive gear, causing the input impedance of the LNA to shift toward low impedance and the output impedance to shift toward high impedance, away from the 50 ohm input and output loads, causing mismatch and affecting the gain of the LNA.

[0095] In response to the above defects, the input impedance is matched through a T-type matching network composed of an inductive circuit, a first series capacitor array and a second series capacitor array to overcome the influence of the input matching circuit on the input impedance and output impedance of the LNA.

[0096] In one possible implementation, Figure 2The LNA shown also includes a first isolation network and a second isolation network. The third end of the first switch circuit is coupled to the second end of the second series capacitor array through the first isolation network, and the third end of the second switch circuit is coupled to the second end of the second series capacitor array through the second isolation network. When the RF signal is input from the first end of the first switch circuit and the LNA works in the first state, the first isolation network is disconnected; when the RF signal is input from the first end of the first switch circuit and the LNA works in the second state, the first isolation network is turned on. By introducing the isolation network, the reverse isolation of the LNA can be improved, that is, the influence of the output signal of the LNA on the input signal can be reduced.

[0097] In one example, Figure 3 The following diagram shows the structures of four types of isolated networks. Figure 3 As shown in Figure A of FIG. 1 , the isolation network can be realized by a switch circuit. The first end and the second end of the switch circuit are respectively the first end and the second end of the isolation network. When the first end and the second end of the switch circuit are connected, the first end and the second end of the isolation network are connected; when the first end and the second end of the switch circuit are disconnected, the first end and the second end of the isolation network are disconnected.

[0098] like Figure 3 As shown in Figure B of FIG. 1 , the isolation network includes a third switch circuit and a fourth switch circuit, wherein the first end of the third switch circuit is coupled to the first end of the isolation network, the second end of the third switch circuit is coupled to the first end of the second switch circuit, the second end of the fourth switch circuit is grounded, and the second end of the third switch circuit is coupled to the second end of the isolation network. When the first end and the second end of the third switch circuit are turned on, and the first end and the second end of the fourth switch circuit are turned off, the first end and the second end of the isolation network are turned on; when the first end and the second end of the fourth switch circuit are turned on, regardless of whether the first end and the second end of the third switch circuit are turned off or on, the first end and the second end of the isolation network are turned off.

[0099] like Figure 3 As shown in Figure C in FIG. 1 , the isolation network can be realized by a switch circuit. The first end of the switch circuit is the first end and the second end of the isolation network, and the first end of the switch circuit is grounded; when the first end and the second end of the switch circuit are connected, the first end and the second end of the isolation network are disconnected; when the first end and the second end of the switch circuit are disconnected, the first end and the second end of the isolation network are connected.

[0100] like Figure 3As shown in Figure D in , the isolation network includes a third switch circuit, a fourth switch circuit and a fifth switch circuit; wherein the second end of the third switch circuit is coupled to the first end of the fourth switch circuit and the first end of the fifth switch circuit, the second end of the fifth switch circuit is grounded, the first end of the third switch circuit is coupled to the first end of the isolation network, and the second end of the fourth switch circuit is coupled to the second end of the isolation network; when the first end and the second end of the third switch circuit are turned on, the first end and the second end of the fourth switch circuit are turned on, and the first end and the second end of the fifth switch circuit are turned off, the first end and the second end of the isolation network are turned on; when the first end and the second end of the fifth switch circuit are turned off, if the first end and the second end of the third switch circuit are turned off or the first end and the second end of the fourth switch circuit are turned off, the first end and the second end of the isolation network are turned off; when the first end and the second end of the fifth switch circuit are turned on, if the first end and the second end of the third switch circuit are turned off or the first end and the second end of the fourth switch circuit are turned off, the first end and the second end of the isolation network are turned off.

[0101] It should be understood that the first isolation network is Figure 3 One of the four isolation networks shown, the second isolation network is Figure 3 One of the four isolation networks shown. The structure of the first isolation network is the same as or different from the structure of the second isolation network.

[0102] In one example, the switch circuit in the present application can be implemented by a switch device, or by a MOS tube. The switches in the present application, such as K1 and K2, can be implemented by a switch device, or by a MOS tube.

[0103] In a possible implementation, the first common-source amplifier circuit includes multiple first amplifier circuits and a first switch array, the input ends of the multiple first amplifier circuits are the input ends of the common-source amplifier circuit, the output end of each first amplifier circuit in the multiple first amplifier circuits is coupled to the first end of a switch in the first switch array, wherein the second end of the switch in the first switch array is the output end of the common-source amplifier circuit, and the opening and closing of the switches in the first switch array are controlled to adjust the gain of the common-source amplifier circuit.

[0104] Each first amplifier circuit includes at least one MOS tube, the gate of the at least one MOS tube is coupled together to form the input end of the first input amplifier circuit, the drain of each MOS tube in the at least one MOS tube is grounded through an inductor, and the source of the at least one MOS tube is coupled together to form the output end of the first input amplifier circuit.

[0105] It should be pointed out here that the number of MOS tubes in the first amplifier circuit is related to the gain of the first amplifier circuit. The more MOS tubes there are in the first amplifier circuit, the larger the total gate width of the first amplifier circuit, and the greater the gain of the MOS tubes in the first amplifier circuit; the fewer MOS tubes there are in the first amplifier circuit, the smaller the total gate width of the first amplifier circuit, and the smaller the gain of the MOS tubes in the first amplifier circuit.

[0106] For a multi-input LNA, the frequency of the RF signal input from the input end of the first common-source amplifier circuit is different from the frequency of the RF signal input from the input end of the second common-source amplifier circuit; the higher the frequency of the input RF signal, the larger the total gate width of the first amplifier circuit in the corresponding common-source amplifier circuit.

[0107] It should be understood that the number of MOS transistors in the multiple first amplifier circuits may be different or the same. When the number of MOS transistors is the same, the sizes of the MOS transistors belonging to different first amplifier circuits may be different.

[0108] like Figure 4 As shown, the common source amplifier circuit includes three first amplifier circuits and a first switch array, each of which is composed of three parallel MOS tubes, and the first switch array includes three switches. The gates of the three MOS tubes are coupled together to form the input end of the first amplifier circuit; the sources of the three MOS tubes are coupled together and coupled to one end of a switch of the first switch array, and the other end of the switch is the output end of the common source amplifier circuit; the drains of the three MOS tubes are coupled together and grounded through an inductor.

[0109] It should be understood that Figure 4 This is just an example and not a limitation of this embodiment. In another example, the gain of the common source amplifier circuit is fixed, that is, the common source amplifier circuit does not include the first switch array, and the output ends of the multiple first amplifier circuits included in the common source amplifier circuit constitute the output end of the common source amplifier circuit.

[0110] In a possible implementation, the common-gate amplifier circuit includes a plurality of second amplifier circuits and a second switch array, the input ends of the plurality of second amplifier circuits are the input ends of the common-gate amplifier circuit, the output ends of the plurality of second amplifier circuits are the output ends of the common-gate amplifier circuit, the control end of each second amplifier circuit in the plurality of second amplifier circuits is coupled to a first end of a switch in the second switch array, and the other end of the switch is coupled to a power supply V DD coupling; controlling the operating state of the second amplifier circuit by controlling the opening and closing of the switches in the second switch array to adjust the gain of the common-gate amplifier circuit.

[0111] Among them, each second amplifier circuit includes at least one MOS tube, the gate of at least one MOS tube is coupled together to form the control end of the second input amplifier circuit, the drain of at least one MOS tube is coupled together to form the output end of the second amplifier circuit, and the source of at least one MOS tube is coupled together to form the input end of the first input amplifier circuit.

[0112] like Figure 5 As shown, the common-gate amplifier circuit includes three second amplifier circuits, each of which is composed of three parallel MOS tubes. The gates of the three MOS tubes are coupled together to form the control end of the first amplifier circuit, and the control end is coupled to the power supply V through the switch in the second switch array. DD ; The sources of the three MOS tubes are coupled together to form the input end of the first amplifier circuit; the drains of the three MOS tubes are coupled together to form the output end of the second amplifier circuit.

[0113] It should be understood that Figure 5 This is just an example and is not a limitation of this embodiment. In another example, the gain of the common-gate amplifier circuit is fixed, that is, the common-gate amplifier circuit does not include a second switch array, and the control terminals of the plurality of second amplifier circuits included in the common-gate amplifier circuit are directly coupled to the power supply V DD , so that the multiple second amplifier circuits included in the common-gate amplifier circuit are all in working state.

[0114] In a possible implementation, the capacitance of the first series capacitor array can be adjusted, and the capacitance of the second series capacitor array can also be adjusted. Figure 6a As shown, the first series capacitor array includes multiple capacitors and multiple switches; wherein the multiple capacitors are connected in series with the multiple switches respectively, and the structure of the switches and capacitors connected in series is then connected in parallel. In other words, the first end of each capacitor in the multiple capacitors is coupled with the second end of the corresponding switch, the first ends of the multiple switches constitute the first end of the first series capacitor array, and the second ends of the multiple capacitors constitute the second end of the first series capacitor array; or, the first ends of the multiple switches constitute the second end of the first series capacitor array, and the second ends of the multiple capacitors constitute the first end of the first series capacitor array. The capacitance of the first series capacitor array is adjusted by opening and closing the switches in the first series capacitor array.

[0115] Optionally, the structure of the second series capacitor array is the same as the structure of the first series capacitor array.

[0116] The structure of a two-input LNA is described above. Based on the above circuit structure, a multi-input LNA can be obtained, such as Figure 6b shown.

[0117] It can be seen that in the solution of the present application, for a multi-input LNA, by multiplexing the common-gate amplifier circuits in the LNA, the number of common-gate amplifier circuits in the LNA is reduced compared to the prior art, which is beneficial to reducing the layout area of ​​the circuit and reducing the hardware cost.

[0118] For different RF signals, the gain requirements are different. High gain requirements can be met by the active position of the cascode amplifier circuit, and low gain requirements can be met by the passive position of the bypass. When the layout area of ​​the circuit board is sufficient, the solution adopted is as follows Figure 7a As shown in the figure: the RF signal with low gain requirement is input to the bypass circuit through the RF input port to meet the low gain requirement; the RF signal with high gain requirement is input to the input matching circuit through the RF input port, and then input to the Cascode amplifier circuit by the input matching circuit to meet the high gain requirement. Among them, Gain0-Gain8 is the gain of the active gear, and the gain difference between two adjacent gears is 3dB. Gain9-Gain10 is the gain of the passive gear, and the gain difference between two adjacent gears is also 3dB.

[0119] When considering saving pad spacing, use Figure 7b Solution: The RF signal is input to the input matching circuit through the RF input port, and then input to the switch circuit by the input matching circuit; the RF signal is input to the Cascode amplifier circuit or bypass circuit by controlling the switch circuit. However, this method will increase the mutual interference between the two gain paths, causing performance degradation. Figure 8 for Figure 7b A specific schematic diagram of the circuit diagram shown. Figure 8 As shown, when the active gear is working, the switch K1 of the passive gear is closed, the switch K2 is closed, and the output of the common-gate amplifier circuit matches the output impedance of the LNA through Ld, the first series capacitor array and the second series capacitor matching array. When the passive gear is working, the switch K2 of the passive gear is closed, and the switch K1 is closed. Due to the increase in the input matching circuit, the input and output impedance of the LNA needs to be matched to a suitable range through a T-type matching network. At this time, all power supplies in the LNA are disconnected, and the input and output impedance of the LNA are matched through the inductor Ld, the first series capacitor array and the second series capacitor array.

[0120] However, when working in the active position, only when switching from the high-frequency gain position to the low-frequency gain position, switches K1 and K2 are both closed, and the second series capacitor matching array is used as a parallel load to achieve low-frequency output impedance tuning. When only the high-frequency gain position is used, switches K1 and K2 are both in the open state. At this time, the turned-off switch K1 and the second series capacitor array will affect the linearity of the LNA output as a parallel capacitive load, causing linearity deterioration; and the second series capacitor array increases the capacitive load effect of the output of the common-gate amplifier front path, causing the LNA output return loss resonance pole to shift to low frequency, pulling the impedance position to the capacitive region, causing the output impedance to be mismatched.

[0121] In order to solve the above technical problems, Fig. 9 As shown, the LNA includes a switch circuit, an amplifier circuit, a first series capacitor array, a second series capacitor array, a matching switch K1 and a grounding switch K2.

[0122] The first end of the switch circuit is coupled to the input end RF_IN of the LNA, the second end of the switch circuit is coupled to the input end of the amplifier circuit, and the power supply V DD The first series capacitor array is coupled to the output end of the amplifier circuit, the input end of the first series capacitor array and one end of the matching switch K1 are both coupled to the output end of the amplifier circuit, the third end of the switch circuit and one end of the grounding switch K2 are coupled to the first end of the second series capacitor array, the other end of the grounding switch K2 is grounded, the second end of the second series capacitor array is coupled to the other end of the matching switch K1, and the second end of the first series capacitor array is coupled to the output end RF_OUT of the LNA.

[0123] Optional, Fig. 9 The LNA shown further includes an input matching circuit, and the first end of the switch circuit is coupled to the input end of the LNA through the input matching circuit, so that the input RF signal matches the input impedance of the LNA.

[0124] When the LNA operates in the first state, the first end of the switch circuit is connected to the second end of the switch circuit, and when the input RF signal is the first RF signal, the matching switch K1 is disconnected, the ground switch K2 is closed, and the amplifier circuit is used to amplify the first RF signal; the amplified first RF signal matches the output impedance of the LNA through the first series capacitor array; when the input RF signal is the second RF signal, the matching switch K1 and the ground switch K2 are both closed, and the amplifier circuit is used to amplify the first RF signal, and the amplified first RF signal matches the output impedance of the LNA through the first series capacitor array and the second series capacitor array.

[0125] When the LNA operates in the second state, the first end of the switch circuit is connected to the second end of the switch circuit, and the matching switch K1 and the grounding switch K2 are turned on; the input RF signal matches the input impedance and output impedance of the LNA through the first series capacitor array and the second series capacitor array.

[0126] Optional, Fig. 9 The LNA shown also includes an inductive circuit and an attenuator. One end of the inductive circuit is coupled to the power supply VDD, and the other end is coupled to the output end of the amplifier circuit, the first end of the matching switch K1, and the first end of the first series capacitor array. The input end of the attenuator is coupled to the second end of the first series capacitor array, and the output end of the attenuator is coupled to the output end of the LNA.

[0127] When the first RF signal is input from the first end of the first switch circuit and the LNA is working in the first state, the amplified first RF signal matches the output impedance of the LNA through the inductive circuit and the first series capacitor array; when the second RF signal is input from the first end of the first switch circuit and the LNA is working in the first state, the amplified second RF signal matches the output impedance of the LNA through the inductive circuit, the first series capacitor array and the second series capacitor array. The attenuator is used to adjust the power of the RF signal output by the common-gate amplifier circuit.

[0128] When the RF signal is input from the first end of the first switch circuit and the LNA operates in the second state, the RF signal matches the input impedance and output impedance of the LNA through the inductive circuit, the first series capacitor array and the second series capacitor array. It should be understood that the RF signal here is a high-frequency RF signal or a low-frequency RF signal. The attenuator is used to adjust the power of the RF signal input from the first end of the first switch circuit.

[0129] Optionally, the inductive circuit is implemented based on an inductor, or based on a PMOS current mirror. Optionally, the inductor here is an inductor with a fixed inductance, or an inductor with an adjustable inductance.

[0130] The frequency of the first RF signal is higher than the frequency of the second RF signal. In one example, the first RF signal is a high-frequency RF signal, and the second RF signal is a low-frequency RF signal. The frequency difference between the first RF signal and the second RF signal is not less than 200 MHz.

[0131] It should be noted that the low-frequency RF signal here refers to a signal with a frequency lower than the first frequency threshold, and the high-frequency RF signal refers to a signal with a frequency higher than the second frequency threshold. Optionally, the first frequency threshold is 2.1 GHz or other values, and the second frequency threshold is 2.3 GHz or other values.

[0132] The first state is an active gain state, and the second state is a passive gain state.

[0133] In other words, when the LNA works in the Active gain state, the first and second ends of the control switch circuit are turned on, and in the high-frequency amplification state, the control switch K1 is turned off and the switch K2 is turned on; in the low-frequency amplification state, the control switches K1 and K2 are both turned on. At this time, the high-frequency RF signal is input to the amplifier circuit, and the amplifier circuit amplifies the input RF signal. The amplified signal is matched to the output impedance through the inductive circuit and the first series capacitor array; in the low-frequency case, the low-frequency RF signal is input to the amplifier circuit, and the amplifier circuit amplifies the input RF signal. The amplified RF signal is matched to the output impedance of the LNA through the inductive circuit, the first series capacitor array, and the second series capacitor array, and then output through the output end of the attenuator.

[0134] When the LNA works in the passive gain state, the first port and the third port of the control switch circuit are turned on, the switch K1 and the isolation network are turned on, and the switch K2 is turned off. DD At this time, the RF signal is input through the isolation network, and the LNA input and output impedance is matched to a suitable range through the T-type matching network composed of the inductive circuit, the first series capacitor array, and the second series capacitor array.

[0135] The gain of the LNA in the Active gain state has 9 levels, and the difference between adjacent gain levels is 3 dB. The gain in the Active gain state is adjusted by controlling the gain of the amplifier circuit and / or the attenuation of the attenuator.

[0136] In one example, the attenuation of the attenuator is adjusted to adjust the power of the radio frequency signal output by the amplifier circuit, thereby achieving the purpose of adjusting the gain of the LNA. At this time, the gain of the amplifier circuit is fixed.

[0137] In another example, the power of the radio frequency signal output by the amplifier circuit is adjusted by adjusting the number of MOS tubes in the amplifier circuit, thereby adjusting the gain of the LNA. At this time, the output gain adjustment of the LNA does not include adjustment by an attenuator.

[0138] In another example, the power of the radio frequency signal output by the amplifier circuit is adjusted by the gain of the amplifier circuit and the attenuation of the attenuator, thereby adjusting the gain of the LNA.

[0139] The gain of the LNA in the passive gain state has two levels. The gain difference between the two levels is 3dB. The gain in the passive gain state is adjusted by controlling the attenuation of the attenuator.

[0140] It should be pointed out that Figure 7a , Figure 7b , Figure 8 and Fig. 9 The middle gray cylinder is the path of the RF signal from the outside of the LNA Die to the inside of the Die, generally referring to the input signal from the substrate to the inside of the Die, and is specifically implemented in the form of a copper pill or a solder ball.

[0141] The capacitance of the first series capacitor array and the capacitance of the second series capacitor array are both adjustable.

[0142] When the LNA works in the active gain state, by adjusting the capacitance of the first series capacitor array and / or the capacitance of the second series capacitor array, the inductive circuit, the first series capacitor array and the second series capacitor array match the output impedance of the LNA, and the output return loss pole of different frequency bands is moved, so that the output impedance of the LNA is matched to 50 ohms and the maximum power transmission is achieved. When the LNA works in the passive gain state, by adjusting the capacitance of the first series capacitor array and / or the capacitance of the second series capacitor array, the inductive circuit, the first series capacitor array and the second series capacitor array match the input impedance and output impedance of the LNA. The purpose of matching the input impedance here is: when the LNA works in the passive gain state, the RF signal enters the LNA through the input matching circuit. The input matching circuit has an impact on the RF signal. For example, the input matching circuit will affect the matching pole, input impedance and output impedance of the Passive gear, causing the input impedance to shift to a low impedance state and the output impedance to shift to a high impedance state away from the 50 ohm input and output loads, causing mismatch and affecting the gain. By matching the input impedance through the inductive circuit, the first series capacitor array and the second series capacitor array, the impact of the input matching circuit on the RF signal can be overcome.

[0143] Compared to Figure 8 The technical solution shown in the figure, the solution of the present application lacks the grounding capacitor array, by controlling Fig. 9 In the circuit shown, switches K1 and K2 are closed, so that the second series capacitor array acts as Figure 8 The purpose of reusing the second series capacitor array is achieved by combining the grounded capacitor array in the circuit. The increase of the second series capacitor array and the smaller parasitic capacitance in the amplifier circuit can improve the linearity of the LNA. The reduction of the grounded capacitor array can save the layout area of ​​the circuit. Figure 8 The technical solution shown reduces the grounding capacitor array, so that the parallel capacitive load at the output end of the amplifier circuit is reduced, so that the resonance point during high-frequency amplification is shifted to high frequency, and the impedance at the harmonic can be suppressed by increasing the capacitance value in the first series capacitor array, suppressing the common-gate harmonic voltage amplitude and thus suppressing the harmonic power. Figure 8The technical solution shown in FIG. 1 can increase the capacitance of the first series capacitor array due to the smaller common-gate output capacitive load when amplifying high-frequency signals. Figure 8 The technical solution shown makes the impedance of the LNA closer to the output impedance position of the center matching point of the circular diagram, achieving a match to 50 ohms with better linearity.

[0144] Optionally, the LNA further includes an input matching circuit, and the radio frequency signal is input to the first end of the switch circuit through the input matching circuit.

[0145] In a possible implementation, in order to increase the reverse isolation of the LNA, the LNA further includes an isolation network, and the third end of the switch circuit is coupled to the first end of the second series capacitor array through the isolation network. When the LNA operates in an Active gain state, the isolation network is disconnected; when the LNA operates in a Passive gain state, the isolation network is turned on.

[0146] In one possible implementation, the amplifier circuit includes a common-source amplifier circuit and a common-gate amplifier circuit, wherein the input end of the common-source amplifier circuit is the input end of the amplifier circuit, the output end of the common-source amplifier circuit is coupled to the input end of the common-gate amplifier circuit, and the output end of the common-gate amplifier circuit is the output end of the amplifier circuit.

[0147] Optionally, the gain of the common-source amplifier circuit is adjustable or fixed. Optionally, the gain of the common-gate amplifier circuit is adjustable or fixed.

[0148] It should be pointed out here that the specific structure of the isolated network can be found in Figure 3 The structure shown in the figure, the specific structure of the common source amplifier circuit and the common gate amplifier circuit can be found in Figure 4 and Figure 5 The structure shown in FIG. 1 is not described here. The specific structure of the first capacitor array and the second capacitor array can be found in FIG. Figure 6a The structure shown will not be described again here.

[0149] In a possible implementation, when the LNA has multiple inputs, that is, when the LNA is a multi-input LNA, there are multiple common-source amplifier circuits, there are multiple switch circuits, and the multiple common-source amplifier circuits correspond to the multiple switch circuits;

[0150] The first ends of the multiple switch circuits are coupled to the multiple input ends of the LNA, the second end of each switch circuit is coupled to the input end of the common source amplifier circuit corresponding to the switch circuit, and the output ends of the multiple common source amplifier circuits are coupled to the input end of the common gate amplifier circuit; the third ends of the multiple switch circuits are coupled to the first end of the second series capacitor array. For the specific structure, please refer to Figure 2 The relevant description of the LNA is not described here.

[0151] In a possible implementation, the LNA further includes a plurality of isolation networks, and the third ends of the plurality of switch circuits are respectively coupled to the first end of the second series capacitor array through the plurality of isolation networks. Figure 2 The relevant description of the LNA is not described here.

[0152] It should be pointed out here that Fig. 9 The LNA shown is for a single frequency RF input.

[0153] It should be understood that Figure 2 The multi-input LNA shown and Figure 6b The multi-input LNA shown can process RF signals of multiple different frequencies, but can only process RF signals of one frequency at a time, and cannot process RF signals of multiple frequencies at the same time.

[0154] The embodiments of the present application are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. At the same time, for general technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A low noise amplifier LNA, characterized in that: The LNA includes a first switch circuit, a second switch circuit, a first common-source amplifier circuit, a second common-source amplifier circuit, a common-gate amplifier circuit, a first series capacitor array, a second series capacitor array, a matching switch K1 and a grounding switch K2. A first end of the first switch circuit is coupled to a first input end of the LNA, and a second end of the first switch circuit is coupled to an input end of the first common-source amplifier circuit. A first end of the second switch circuit is coupled to a second input end of the LNA, and a second end of the second switch circuit is coupled to an input end of the second common-source amplifier circuit. The output end of the first common-source amplifier circuit and the output end of the second common-source amplifier circuit are both coupled to the input end of the common-gate amplifier circuit. The output end of the common-gate amplifier circuit is coupled to the power supply V DD and coupled to the output end of the LNA through the first series capacitor array, The third terminal of the first switch circuit and the third terminal of the second switch circuit are coupled to the power supply V through the second series capacitor array. DD and coupled to the output end of the LNA through the first series capacitor array, The second series capacitor array is coupled to the power supply V through the matching switch K1. DD and the first series capacitor array, wherein the first end of the matching switch K1 is coupled to the first end of the first series capacitor array, and the second end of the matching switch K1 is coupled to the first end of the second series capacitor array, The first end of the grounding switch K2 is coupled between the first switch circuit, the second switch circuit and the second end of the second series capacitor array, wherein the second end of the grounding switch K2 is grounded, and the second end of the first series capacitor array is coupled to the output end of the LNA.

2. The LNA according to claim 1, characterized in that If the first RF signal is input from the first end of the first switch circuit and the LNA is operating in the first state, the first end and the second end of the first switch circuit are controlled to be turned on, the matching switch K1 is controlled to be turned off and the grounding switch K2 is controlled to be turned on, The common-gate amplifier circuit and the first common-source amplifier circuit are used to amplify the first radio frequency signal; The amplified first radio frequency signal is matched to the output impedance of the LNA through the first series capacitor array.

3. The LNA according to claim 2, characterized in that If the second RF signal is input from the first end of the first switch circuit and the LNA is operating in the first state, the first end and the second end of the first switch circuit are controlled to be turned on, the matching switch K1 is controlled to be closed, and the grounding switch K2 is controlled to be closed, The common-gate amplifier circuit and the first common-source amplifier circuit are used to amplify the second radio frequency signal; The amplified second radio frequency signal matches the output impedance of the LNA through the first series capacitor array and the second series capacitor array.

4. The LNA according to claim 3, characterized in that The frequency of the first radio frequency signal is higher than the frequency of the second radio frequency signal.

5. The LNA according to any one of claims 1 to 4, characterized in that: When a radio frequency signal is input from the first end of the first switch circuit and the LNA operates in the second state, the first end and the third end of the first switch circuit are controlled to be turned on, the matching switch K1 is controlled to be closed and the grounding switch K2 is controlled to be opened, The radio frequency signal matches the input impedance and output impedance of the LNA through the first series capacitor array and the second series capacitor array.

6. The LNA according to claim 5, characterized in that When the LNA operates in the second state, the power supply V DD Power off.

7. The method according to any one of claims 2 to 6, characterized in that: The LNA also includes: an inductive circuit and an attenuator; The inductive circuit is coupled to the output terminal of the common-gate amplifier circuit, the first terminal of the first series capacitor array, the first terminal of the matching switch K1, and the power supply V DD The input end of the attenuator is coupled to the second end of the first series capacitor array, and the output end of the attenuator is coupled to the output end of the LNA; The amplified first radio frequency signal matches the output impedance of the LNA through the first series capacitor array, including: The amplified first radio frequency signal matches the output impedance of the LNA through the inductive circuit and the first series capacitor array; The amplified second radio frequency signal matches the output impedance of the LNA through the first series capacitor array and the second series capacitor array, including: The amplified second radio frequency signal matches the output impedance of the LNA through the inductive circuit, the first series capacitor array and the second series capacitor array; The radio frequency signal matches the input impedance and output impedance of the LNA through the first series capacitor array and the second series capacitor array, including: The radio frequency signal matches the input impedance and output impedance of the LNA through the inductive circuit, the first series capacitor array, and the second series capacitor array; The attenuator is used to adjust the power of the radio frequency signal output by the common-gate amplifier circuit, or to adjust the power of the radio frequency signal input from the first end of the first switch circuit.

8. The LNA according to any one of claims 2 to 7, characterized in that: The LNA further comprises a first isolation network and a second isolation network, wherein the third end of the first switch circuit is coupled to the second end of the second series capacitor array via the first isolation network; the third end of the second switch circuit is coupled to the second end of the second series capacitor array via the second isolation network; When the LNA operates in the first state, the first isolation network is disconnected; when the LNA operates in the second state, the first isolation network is turned on.

9. The LNA according to claim 8, characterized in that The first isolation network includes a third switch circuit, a fourth switch circuit and a fifth switch circuit; Wherein, the second end of the third switch circuit is coupled to the first end of the fourth switch circuit and the first end of the fifth switch circuit, the second end of the fifth switch circuit is grounded, the first end of the third switch circuit is coupled to the first end of the first isolation network, and the second end of the fourth switch circuit is coupled to the second end of the first isolation network; When the first end and the second end of the third switch circuit are turned on, the first end and the second end of the fourth switch circuit are turned on, and the first end and the second end of the fifth switch circuit are turned off, the first end and the second end of the first isolation network are turned on; on the premise that the first end and the second end of the fifth switch circuit are turned off, if the first end and the second end of the third switch circuit are turned off or the first end and the second end of the fourth switch circuit are turned off, the first end and the second end of the first isolation network are turned off; when the first end and the second end of the fifth switch circuit are turned on, if the first end and the second end of the third switch circuit are turned off or the first end and the second end of the fourth switch circuit are turned off, the first end and the second end of the first isolation network are turned off.

10. The LNA according to any one of claims 1 to 9, characterized in that: The first common-source amplifier circuit includes a plurality of first amplifier circuits and a first switch array, wherein the input end of the plurality of first amplifier circuits is the input end of the common-source amplifier circuit, and the output end of each first amplifier circuit in the plurality of first amplifier circuits is coupled to the first end of a switch in the first switch array, wherein the second end of the switch in the first switch array is the output end of the common-source amplifier circuit, The switches in the first switch array are controlled to be opened and closed to adjust the gain of the common-source amplifier circuit.

11. The LNA according to any one of claims 1 to 10, characterized in that: The common-gate amplifier circuit includes a plurality of second amplifier circuits and a second switch array, wherein the input end of the plurality of second amplifier circuits is the input end of the common-gate amplifier circuit, the output end of the plurality of second amplifier circuits is the output end of the common-gate amplifier circuit, the control end of each second amplifier circuit in the plurality of second amplifier circuits is coupled to the first end of a switch in the second switch array, and the other end of the switch is coupled to the power supply V DD coupling; The working state of the second amplifier circuit is controlled by controlling the opening and closing of the switches in the second switch array to adjust the gain of the common-gate amplifier circuit.

12. The LNA according to any one of claims 1 to 11, characterized in that: The first series capacitor array includes a plurality of capacitors and a plurality of switches, wherein the plurality of switches correspond to the plurality of capacitors; The first end of the plurality of switches is the first end of the first series capacitor array, the second end of each switch in the plurality of switches is coupled to the first end of the capacitor corresponding to the switch, and the second end of the plurality of capacitors is the second end of the first series capacitor array; The switches in the first series capacitor array are controlled to be opened and closed to adjust the capacitance of the first series capacitor array.

13. A radio frequency front-end chip, characterized in that: The method comprises a low noise amplifier LNA as claimed in any one of claims 1 to 12.

14. An electronic device, characterized in that: The electronic device includes the low noise amplifier LNA as described in any one of claims 1 to 12, or includes the radio frequency front-end chip as described in claim 13.

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