High-linearity amplifier with filtering function

Abstract

The invention provides a high-linearity amplifier with a filtering function. The high-linearity amplifier comprises an input matching network, a bias network A, a bias network B, a feedback network, a filtering network, an amplifying circuit and an output matching network, a Cascode circuit structure is adopted to form an amplifying circuit, and gain flatness and good input and output matching are guaranteed through an RC feedback network. Transistor bias voltage which slightly fluctuates along with temperature change is provided for the amplifier through the bias network A and the bias network B, so that stability of static current of the whole amplifier along with temperature change is guaranteed. The low-pass filtering function is achieved by introducing the filtering network into the amplifier, high-frequency harmonic and clutter suppression of the amplifier is improved, meanwhile, the linearity of an amplification circuit is improved by optimizing the structures of the bias network A, the bias network B and the filtering network, and the design flexibility of the amplifier is improved.

Description

Technical Field

[0001] The invention belongs to the field of semiconductor integrated circuit design, and in particular relates to a high linearity amplifier with a filtering function. Background Art

[0002] Wireless communication systems have increasingly higher requirements for signal quality, especially for RF systems that include frequency sources, including RF, local oscillator and intermediate frequency signals. In the process of signal frequency conversion, in order to obtain the required signal in the signal channel, it is necessary to perform signal processing such as harmonic suppression and image suppression. In order to eliminate unnecessary signals in the signal channel, specific filters are required to filter out the signal, including low-pass filters, high-pass filters, band-pass filters and other components. Therefore, in the process of signal processing, filters are often used components for special requirements such as harmonic suppression and clutter suppression. Low passband insertion loss, high stopband suppression, and wide operating frequency band have become the main technical indicators that the system focuses on.

[0003] At present, in order to filter and select signals in the RF channel, it is generally necessary to introduce independent filter unit circuits. Some application scenarios use chip filter unit circuits, which use more capacitors and inductors and occupy a larger chip area; other application scenarios use discrete filter unit circuits, which occupy more area and volume in the RF system, which is not conducive to miniaturization design. In order to save chip area and improve system integration, application scenarios such as phased array radar, electronic countermeasures, and satellite communications have certain requirements for high-linearity amplifiers with filtering functions. The linearity of the amplifier determines the dynamic range of the RF transceiver system. The filtering function of the amplifier will further reduce the out-of-band useless signals through harmonic suppression and clutter suppression, while reducing the performance requirements of other components in the link. At the same time, the filtering function designed in conjunction with the amplifier reduces the number of capacitors and inductors, thereby saving chip area and being more conducive to the development trend of high integration.

[0004] In RF systems with high signal quality requirements, the RF amplifier is not only required to have high output second-order intermodulation and output third-order intermodulation, but also has high requirements for clutter suppression or harmonic suppression indicators. An amplifier with a filtering function can not only amplify the required signal, but also meet the characteristics of high-order harmonic suppression and filtering, and meet the needs of the RF system for high anti-interference ability and high spurious-free dynamic range of the RF system. Therefore, designing and inventing a high-linearity amplifier with a filtering function has important research significance and application value. Summary of the invention

[0005] In order to solve the problems existing in the background technology, the present invention provides a high linearity amplifier with filtering function, which realizes the design of an amplifier with filtering function with better performance index, smaller size and higher integration, improves system integration and enhances system performance.

[0006] In order to achieve the above technical purpose, the present invention provides a high linearity amplifier with filtering function, comprising: an input matching network, a bias network A, a bias network B, a feedback network, a filtering network, an amplifying circuit and an output matching network;

[0007] The input end of the input matching network serves as the signal input end of the high linearity amplifier; the output end thereof is connected to the output end of the feedback network and the second input end of the filter network;

[0008] The first input end of the filter network is connected to the output end of the bias network B; the first output end of the filter network is connected to the first input end of the amplifier circuit; the second output end of the filter network is connected to the second input end of the amplifier circuit, and the third output end of the filter network is connected to the third input end of the amplifier circuit;

[0009] The output end of the amplifier circuit, the first input end of the bias network B, the input end of the bias network A, the first input end of the feedback network and the first input end of the output matching network are connected;

[0010] The second input end of the bias network B is connected to the first output end of the bias network A; the second output end of the bias network A is connected to the second input end of the feedback network;

[0011] The second input end of the output matching network is connected to the power supply end; the output end of the output matching network serves as the output end of the high linearity amplifier.

[0012] The present invention has at least the following beneficial effects

[0013] The present invention adopts the architecture of Cascode amplifier circuit, adopts resistor and capacitor negative feedback structure to improve the gain flatness of amplifier, and adopts bias network A and bias network B to improve the temperature stability of bias voltage and amplifier working current. At the same time, a filter network is introduced in the amplifier to form a filter characteristic with the parasitic parameters of other components and transistors in the amplifier, which reduces the components needed to form the filter network, so that the amplifier can have low-pass filter characteristics and can also participate in the improvement of impedance matching and high linearity. The amplifier does not need to cascade a separate filter circuit unit, and the introduced filter network is collaboratively designed with the entire amplifier circuit structure to have good filtering characteristics outside the working frequency band, ensuring high-frequency harmonic suppression and clutter suppression, reducing the chip area and improving the integration. Under the conditions of 5V power supply voltage and 90mA current, the power gain reaches more than 17dB, and within the bandwidth range of 0.01GHz to 1.5GHz, the output third-order intermodulation point power can reach more than 30dBm, and the output second-order intermodulation point power can reach more than 50dBm, with filtering characteristics, and reaches the indicators of high gain flatness and high linearity within the working frequency range. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0015] Figure 2 A schematic diagram of the structure of an embodiment of an input matching network of the present invention;

[0016] Figure 3 Schematic diagram of the structure of a bias network A according to an embodiment of the present invention;

[0017] Figure 4 Schematic diagram of the structure of a bias network B according to an embodiment of the present invention;

[0018] Figure 5 It is a schematic diagram of the structure of an embodiment of the feedback network of the present invention;

[0019] Figure 6 It is a schematic diagram of the structure of an embodiment of the filter network of the present invention;

[0020] Figure 7 It is a schematic diagram of the structure of an embodiment of the amplifier circuit of the present invention;

[0021] Figure 8 A schematic diagram of the structure of an output matching network according to an embodiment of the present invention;

[0022] Fig. 9 It is a schematic diagram of power gain and flatness parameters of the present invention;

[0023] Fig.10 This is a schematic diagram of the output third-order intercept point power parameters of the present invention;

[0024] Fig.11 It is a schematic diagram of the output second-order intercept point power parameters of the present invention. DETAILED DESCRIPTION

[0025] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0026] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0027] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0028] See also Figure 1 The present invention provides a high linearity amplifier with filtering function, comprising:

[0029] Input matching network, bias network A, bias network B, feedback network, filter network, amplifier circuit and output matching network;

[0030] The input end 1 of the input matching network serves as the signal input end of the high linearity amplifier; the output end 2 thereof is connected to the output end 3 of the feedback network and the second input end 2 of the filter network;

[0031] The first input terminal 1 of the filter network is connected to the output terminal 3 of the bias network B; the first output terminal 3 of the filter network is connected to the first input terminal 1 of the amplifier circuit; the second output terminal 4 of the filter network is connected to the second input terminal 2 of the amplifier circuit, and the third output terminal 5 of the filter network is connected to the third input terminal 3 of the amplifier circuit;

[0032] The output terminal 4 of the amplifier circuit, the first input terminal 1 of the bias network B, the input terminal 1 of the bias network A, the first input terminal 1 of the feedback network and the first input terminal 1 of the output matching network are connected;

[0033] The second input terminal 2 of the bias network B is connected to the first output terminal 2 of the bias network A; the second output terminal 3 of the bias network A is connected to the second input terminal 2 of the feedback network;

[0034] The second input terminal 3 of the output matching network is connected to the power supply terminal; the output terminal 2 of the output matching network serves as the output terminal of the high linearity amplifier.

[0035] See also Figure 2 , embodiment, the input matching network is mainly used for input stage port matching of the amplifier circuit, ensuring good input return loss index of the amplifier input port and providing DC isolation; in this embodiment, a common input matching network implementation method is provided, and the input matching network includes: a capacitor C1; one end of the capacitor C1 serves as the input end 1 of the input matching network, and the other end of the capacitor C1 serves as the output end 2 of the input matching network.

[0036] Embodiment, bias network A and bias network B are used to provide bias for transistors of an amplifier circuit. In this embodiment, a specific implementation of bias network A and bias network B is provided:

[0037] See also Figure 3 , the bias network A includes: resistors R7~R 13 , N-type MOS transistors M3-M6, capacitor C6 and capacitor C7;

[0038] One end of the resistor R7 is connected to the second output terminal 3 of the bias network A; the other end of the resistor R7, the source of the transistor M3, one end of the resistor R9 and the resistor R 10 The other end of the resistor R9 is grounded; the gate of the transistor M3, one end of the capacitor C6, the resistor R 13 One end of the transistor M5, the drain of the resistor R 11 one end of the capacitor C7 and the resistor R 10 The other end of the transistor M3 is connected to the drain of the transistor M3 and one end of the resistor R8; the other end of the capacitor C6 is connected to the first output end 2 of the bias network A; the resistor R 13The other end is connected to the source of transistor M4; the gate of transistor M4, the source of transistor M5, the drain of transistor M6 and the gate of transistor M6 are connected; the drain of transistor M4 is connected to resistor R 12 One end is connected; the resistor R 12 The other end of the resistor R8 is connected to the input end 1 of the bias network A; the gate of the transistor M5 is connected to the resistor R 11 The source of the transistor M6 and the other end of the capacitor C7 are grounded.

[0039] In this embodiment, the bias network A provides a static operating point for the transistor M1 in the amplifier circuit, and the bias network can ensure a relatively stable bias voltage during temperature changes.

[0040] See also Figure 4 The bias network B includes: resistors R2 to R5 and a capacitor C4, one end of the resistor R2 serves as a first input end 1 of the bias network B; the other end of the resistor R2, one end of the resistor R3, one end of the resistor R4 and a second input end 2 of the bias network B are connected; the other end of the resistor R3 is grounded; the other end of the resistor R4, one end of the resistor R5 and an output end 3 of the bias network B; the other end of the resistor R5 is connected to one end of the capacitor C4; the other end of the capacitor C4 is grounded.

[0041] In this embodiment, the bias network B provides a static operating point for the transistor M2 in the amplifier circuit, and the bias network can ensure a relatively stable bias voltage during temperature changes.

[0042] Embodiment, the feedback network is used to provide good impedance matching for the amplifier circuit, while improving the amplifier power gain and stability. This embodiment provides an implementation method of the feedback network:

[0043] See also Figure 5 The feedback network includes: a capacitor C5 and a resistor R6; one end of the capacitor C5 serves as a first input end 1 of the feedback network; the other end of the capacitor C5, one end of the resistor R6 and a second input end 2 of the feedback network are connected; the other end of the resistor R6 serves as an output end 3 of the feedback network.

[0044] Embodiment, the filter network is used to provide filtering characteristics for the amplifier circuit, and provide the function of harmonic and clutter suppression; this embodiment provides an implementation method of a filter network:

[0045] See also Figure 6The filter network includes: capacitor C2, capacitor C3, inductor L1 and inductor L2; one end of the inductor L1, one end of the capacitor C2 and the second input end 2 of the filter network are connected; the other end of the inductor L1 serves as the first output end 3 of the filter network; the other end of the capacitor C2, one end of the capacitor C3, one end of the inductor L2 and the first input end 1 of the filter network are connected; the other end of the capacitor C3 serves as the second output end 4 of the filter network; the other end of the inductor L2 serves as the third output end 5 of the filter network.

[0046] Embodiment, the amplifier circuit is used to amplify the radio frequency signal at the input end, provide sufficient power gain, high linearity power characteristics, and also provide a low noise coefficient; the embodiment provides an implementation method of the amplifier circuit:

[0047] See also Figure 7 The amplifier circuit includes: an N-type MOS transistor M1, an N-type MOS transistor M2 and a resistor R1, the gate of the transistor M1 serves as a first input terminal 1 of the amplifier circuit; the source of the transistor M1 is connected to one end of the resistor R1; the other end of the resistor R1 is grounded; the drain of the transistor M1, the source of the transistor M2 and the second input terminal 2 of the amplifier circuit are connected; the gate of the transistor M2 serves as a third input terminal 3 of the amplifier circuit; and the drain of the transistor M2 serves as an output terminal 4 of the amplifier circuit.

[0048] Embodiment, the output matching network is used for matching the output port of the amplifier circuit, providing a DC isolation function, and providing power supply end choke and filtering. This embodiment provides an implementation method of an output matching network:

[0049] See also Figure 8 The output matching network includes: a capacitor C8, a capacitor C9 and an inductor L3; one end of the capacitor C8, one end of the inductor L3 and a first input terminal 1 of the output matching network are connected; the other end of the capacitor C8 is connected to an output terminal 2 of the output matching network; the other end of the inductor L3, one end of the capacitor C9 and a second input terminal 3 of the output matching network are connected; the other end of the capacitor C9 is grounded.

[0050] In this embodiment, the transistors M1, M2, M3, M4, M5 and M6 are transistors of the same type, and the types of the transistors M1, M2, M3, M4, M5 and M6 are GaAs E-pHEMT, GaN E-pHEMT, and NMOS of RF CMOS.

[0051] The working principle of the present invention is as follows:

[0052] Transistor M1 and transistor M2 form a Cascode structural unit, which is the main core unit of the amplifier circuit. Capacitor C5 and resistor R6 form a negative feedback structure to adjust the power gain and impedance matching of the overall amplifier. Resistor R1 forms the source-level negative feedback of the amplifier structure to adjust the circuit power consumption and gain characteristics, while improving the stability of the overall circuit. Inductor L1, inductor L2, capacitor C2, and capacitor C3 form a filtering network to achieve filtering characteristics and suppress high-frequency harmonics and clutter signals. Capacitor C1 forms an input matching network to ensure good input matching characteristics of the circuit. Transistor M3, transistor M4, transistor M5, transistor M6, resistor R7, resistor R8, resistor R9, resistor R 10 , resistor R 11 , resistor R 12 , resistor R 13 , capacitor C6, and capacitor C7 constitute the gate bias network of field effect transistor M1, providing the static operating point of field effect transistor M1. Capacitor C4, resistor R2, resistor R3, resistor R4, and resistor R5 constitute the gate bias network of field effect transistor M2, providing the static operating point of field effect transistor M2. Capacitor C8 and inductor L3 constitute the output matching network of the amplifier circuit, and capacitor C9 filters the power supply. The input and output ends of the entire RF amplifier are matched with capacitors and inductors to ensure good input and output matching characteristics of the circuit. Active bias is used to ensure the stability of the circuit's current with temperature changes. The low-pass filtering characteristics of the amplifier are realized through the filtering network, which improves harmonic suppression and clutter suppression. At the same time, the linearity of the amplifier is also relatively high.

[0053] like Figures 9 to 11 As shown, when the power supply voltage is 5V, the power supply current is 90mA, the power gain reaches more than 17dB, and the gain flatness can reach ±0.3dB in the bandwidth range of 0.01GHz to 1.5GHz. The power gain characteristic drops rapidly to below 0dB at around 2.7GHz, with good filtering characteristics. At the same time, the output third-order intermodulation point power can reach more than 30dBm, and the output second-order intermodulation point power can reach up to more than 50dBm, achieving high linearity indicators within the operating frequency range.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A high linearity amplifier with filtering function, characterized in that: include: Input matching network, bias network A, bias network B, feedback network, filter network, amplifier circuit and output matching network; The input end of the input matching network serves as a signal input end of the high linearity amplifier; Its output end is connected to the output end of the feedback network and the second input end of the filter network; The first input end of the filter network is connected to the output end of the bias network B; the first output end of the filter network is connected to the first input end of the amplifier circuit; the second output end of the filter network is connected to the second input end of the amplifier circuit, and the third output end of the filter network is connected to the third input end of the amplifier circuit; The output end of the amplifier circuit, the first input end of the bias network B, the input end of the bias network A, the first input end of the feedback network and the first input end of the output matching network are connected; The second input terminal of the bias network B is connected to the first output terminal of the bias network A; The second output terminal of the bias network A is connected to the second input terminal of the feedback network; The second input end of the output matching network is connected to the power supply end; the output end of the output matching network serves as the output end of the high linearity amplifier.

2. A high linearity amplifier with filtering function according to claim 1, characterized in that: The input matching network includes: a capacitor C1; one end of the capacitor C1 serves as an input end of the input matching network, and the other end of the capacitor C1 serves as an output end of the input matching network.

3. The high linearity amplifier with filtering function according to claim 1, characterized in that: The bias network A includes resistors R7 to R 13 , N-type MOS transistors M3-M6, capacitor C6 and capacitor C7; One end of the resistor R7 is connected to the second output end of the bias network A; the other end of the resistor R7, the source of the transistor M3, one end of the resistor R9 and the resistor R 10 The other end of the resistor R9 is grounded; the gate of the transistor M3, one end of the capacitor C6, the resistor R 13 One end of the transistor M5, the drain of the resistor R 11 one end of the capacitor C7 and the resistor R 10 The other end of the transistor M3 is connected to the drain of the transistor M3 and one end of the resistor R8; the other end of the capacitor C6 is connected to the first output end of the bias network A; the resistor R 13 The other end is connected to the source of transistor M4; the gate of transistor M4, the source of transistor M5, the drain of transistor M6 and the gate of transistor M6 are connected; the drain of transistor M4 is connected to resistor R 12 One end is connected; the resistor R 12 The other end of the resistor R8 is connected to the input end of the bias network A; the gate of the transistor M5 is connected to the resistor R 11 The source of the transistor M6 and the other end of the capacitor C7 are grounded.

4. The high linearity amplifier with filtering function according to claim 1, characterized in that: The bias network B includes: resistors R2 to R5 and a capacitor C4, one end of the resistor R2 serves as a first input end of the bias network B; the other end of the resistor R2, one end of the resistor R3, one end of the resistor R4 and a second input end of the bias network B are connected; the other end of the resistor R3 is grounded; the other end of the resistor R4, one end of the resistor R5 and an output end of the bias network B; the other end of the resistor R5 is connected to one end of the capacitor C4; the other end of the capacitor C4 is grounded.

5. The high linearity amplifier with filtering function according to claim 1, characterized in that: The feedback network includes: a capacitor C5 and a resistor R6; one end of the capacitor C5 serves as a first input end of the feedback network; the other end of the capacitor C5, one end of the resistor R6 and a second input end of the feedback network are connected; the other end of the resistor R6 serves as an output end of the feedback network.

6. The high linearity amplifier with filtering function according to claim 1, characterized in that: The filtering network includes: capacitor C2, capacitor C3, inductor L1 and inductor L2; one end of the inductor L1, one end of the capacitor C2 and the second input end of the filtering network are connected; the other end of the inductor L1 serves as the first output end of the filtering network; the other end of the capacitor C2, one end of the capacitor C3, one end of the inductor L2 and the first input end of the filtering network are connected; the other end of the capacitor C3 serves as the second output end of the filtering network; the other end of the inductor L2 serves as the third output end of the filtering network.

7. The high linearity amplifier with filtering function according to claim 1, characterized in that: The amplifier circuit includes: an N-type MOS transistor M1, an N-type MOS transistor M2 and a resistor R1, wherein the gate of the transistor M1 serves as a first input terminal of the amplifier circuit; the source of the transistor M1 is connected to one end of the resistor R1; the other end of the resistor R1 is grounded; the drain of the transistor M1, the source of the transistor M2 and the second input terminal of the amplifier circuit are connected; the gate of the transistor M2 serves as a third input terminal of the amplifier circuit; and the drain of the transistor M2 serves as an output terminal of the amplifier circuit.

8. The high linearity amplifier with filtering function according to claim 1, characterized in that: The output matching network includes: a capacitor C8, a capacitor C9 and an inductor L3; one end of the capacitor C8, one end of the inductor L3 and a first input end of the output matching network are connected; the other end of the capacitor C8 is connected to the output end of the output matching network; the other end of the inductor L3, one end of the capacitor C9 and a second input end of the output matching network are connected; the other end of the capacitor C9 is grounded.

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