WO2020000168A1 - 一种前置放大器 - Google Patents

一种前置放大器 Download PDF

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WO2020000168A1
WO2020000168A1 PCT/CN2018/092794 CN2018092794W WO2020000168A1 WO 2020000168 A1 WO2020000168 A1 WO 2020000168A1 CN 2018092794 W CN2018092794 W CN 2018092794W WO 2020000168 A1 WO2020000168 A1 WO 2020000168A1
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capacitor
resistor
transistor
circuit
grounded
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PCT/CN2018/092794
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English (en)
French (fr)
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郑海荣
李烨
陈巧燕
罗超
李柔
贺强
刘新
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深圳先进技术研究院
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Priority to PCT/CN2018/092794 priority Critical patent/WO2020000168A1/zh
Publication of WO2020000168A1 publication Critical patent/WO2020000168A1/zh

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/26—Modifications of amplifiers to reduce influence of noise generated by amplifying elements

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  • the present invention relates to electronic technology, and specifically to a preamplifier.
  • Noise figure is the most important performance indicator of low noise amplifiers. Therefore, in the process of input matching design, noise matching is generally used to achieve the smallest noise figure, instead of matching the input impedance to 50 ohms to achieve the maximum gain. . How to balance the noise figure minimization and gain maximization is a design difficulty.
  • the signal generated by the 1H atom in the magnetic resonance system is on the order of microvolts and must be amplified before it can be processed.
  • a low-noise preamplifier is usually integrated into the receiving coil.
  • the performance of the low-noise preamplifier directly affects the signal-to-noise ratio of the image. Therefore, the design requirement for the low-noise preamplifier is to have a low noise figure while ensuring a sufficiently large gain in order to obtain a higher image signal-to-noise ratio.
  • An embodiment of the present invention provides a preamplifier, which includes: an input matching circuit, an input protection circuit, an amplifying transistor, a negative feedback network, an output matching circuit, a filter circuit, and an output protection circuit; the amplifying transistor passes a resistor (R4) Connected to the output matching circuit;
  • the input matching circuit includes: a capacitor (C1), a capacitor (C2), a capacitor (C3), and an inductor (L1).
  • One end of the capacitor (C1), capacitor (C2), and capacitor (C3) is in phase with the input protection circuit.
  • the other end of the capacitor (C1) is connected to the input port.
  • the capacitor (C2) and the capacitor (C3) are connected in parallel.
  • the other end of the capacitor (C2), capacitor (C3), and the inductor (L1) are connected to the gate of the amplifier transistor. Pole, the other end of the inductor (L1) is grounded;
  • One end of the negative feedback network is connected to the source of the amplifying transistor, and the other end is grounded for adjusting the static operating point.
  • the amplifying transistor is a gallium arsenide enhanced pseudomorphic high electron mobility transistor.
  • the negative feedback network includes a first feedback unit and a second feedback unit. One end of the two feedback units is connected to the source of the amplifying transistor and the other end is grounded.
  • the first feedback unit includes a capacitor (C5), a capacitor (C4), and a resistor (Rs1). One end of the resistor (Rs1) is grounded, and the other end is connected to the source of the amplifying transistor.
  • the capacitor (C5), capacitor (C4) ) Connected in parallel with the resistor (Rs1);
  • the second feedback unit includes: a capacitor (C6), a capacitor (C7), and a resistor (Rs2). One end of the resistor (Rs2) is grounded, and the other end is connected to the source of the amplifier transistor.
  • the capacitor (C6), capacitor (C7) ) Is connected in parallel with the resistor (Rs2).
  • the amplifier further includes a current stabilization circuit, which is connected to the drain of the amplifying transistor through a resistor (R1), and is connected to the output matching circuit through a resistor (R4).
  • the current stabilization circuit includes: a bipolar junction transistor, a resistor (R2), a resistor (R3), a capacitor (C8), and a capacitor (C9);
  • the emitter of the bipolar junction transistor is connected to the drain of the amplifier transistor through a resistor (R1), and the collector of the bipolar junction transistor is connected to the output matching circuit through a resistor (R4);
  • resistor (R2), capacitor (C8), and capacitor (C9) is connected to the base of the bipolar junction transistor.
  • the other ends of the resistor (R2), capacitor (C8), and capacitor (C9) are grounded, and the resistor (R3 One end is connected to the emitter of a bipolar junction transistor, and the other end is connected to a resistor (R2).
  • This application provides a magnetic resonance low noise preamplifier, which uses a gallium arsenide-enhanced pseudomorphic high electron mobility transistor for single-stage amplification, reduces the complexity and cost of the circuit, and uses a negative feedback network in the circuit. It has added a current stabilization circuit module to improve the working stability of the preamplifier and is suitable for more commonly used clinical magnetic resonance systems.
  • FIG. 1 is a structural block diagram of a preamplifier in an embodiment of the present invention
  • FIG. 2 is a circuit diagram of a preamplifier in an embodiment of the present application.
  • An embodiment of the present invention provides a magnetic resonance low-noise preamplifier, which uses a gallium arsenide-enhanced pseudomorphic high electron mobility transistor for single-stage amplification.
  • the circuit includes: an input protection circuit, an input matching circuit, an amplification transistor, a negative The feedback network, current stabilization circuit, output matching circuit, output protection circuit, and filter circuit.
  • the value of the input impedance network in the actual circuit is repeatedly debugged, so that the input impedance is 2-3 ohms, and the noise figure is finally measured. It is 0.46dB and the gain can reach 27dB, which realizes the balance of minimizing the noise figure and maximizing the gain.
  • FIG. 1 it is a structural block diagram of a preamplifier according to an embodiment of the present invention, which includes: an input protection circuit 101, an input matching circuit 102, an amplification transistor 103, a negative feedback network 104, a current stabilization circuit 105, and an output matching circuit. 106. An output protection circuit 107 and a filter circuit 108.
  • the amplification transistor 103 uses a gallium arsenide-enhanced pseudomorphic high electron mobility transistor for single-stage amplification, which reduces the complexity and cost of the circuit; the negative feedback network 104 and the current stabilization circuit 105 are added , Improve the working stability of the preamp; suitable for high-field magnetic resonance systems.
  • FIG. 2 this is a circuit diagram of the preamplifier in the embodiment of the present application.
  • the circuit system includes: an input protection circuit 201, an input matching circuit 202, a negative feedback network 203, an amplifying transistor 204, and a steady current.
  • the amplifying transistor uses a gallium arsenide-enhanced pseudomorphic high electron mobility transistor, the model is ATF-38143, for single-stage amplification; for the static operating point selection of the amplifying transistor, reference is made to the transistor product data The standard values in the table are simulated in the software ADS. Based on the analysis of the above static operating point, a negative feedback bias is adopted for the design of the bias transistor bias circuit.
  • the input protection circuit is implemented by using a diode pair to prevent the signal from being too large and burning the amplifier transistor.
  • the capacitors C1, C2, C3 and the inductor L1 are matching networks at the input terminals of the amplifying transistor.
  • the inductor uses a high-quality non-magnetic hollow inductor.
  • the noise figure and input impedance are mainly realized by fine-tuning the capacitance of the capacitor C3. Optimization.
  • the negative feedback bias network is composed of capacitors C4, C5, resistor Rs1 and capacitors C6, C7, and resistor Rs2.
  • the reverse voltage is obtained by negative feedback of the sources Rs1 and Rs2.
  • the static operating point is mainly adjusted by the resistor Rs1 , Rs2 and R1, R4 to adjust, get stable gain and good linearity.
  • the current stabilization circuit includes a bipolar junction transistor, resistors R2, R3, and capacitors C8 and C9, and functions as a current follower in the circuit to ensure the stability of the power supply current.
  • the matching network at the output end of the amplifying transistor is composed of capacitors C10, C11, C12, and inductor L2.
  • the output impedance matching is mainly achieved by fine-tuning the size of capacitor C10.
  • an inductor L3 and capacitors C13 and C14 are added to the circuit to play a filtering role.
  • the output terminal protection circuit is implemented by using two diode pairs in series. In the case of excessive signal, it protects the amplifier transistor.
  • the amplification transistor uses a gallium arsenide-enhanced pseudomorphic high electron mobility transistor for single-stage amplification, which reduces the complexity and cost of the circuit; a negative feedback network and an increase are used in the circuit
  • the current stabilization circuit module is improved to improve the working stability of the preamplifier.
  • the preamplifier in the embodiment of the present application has a relatively simple circuit, which reduces the cost; a negative feedback method and a current stabilization circuit are added to improve the preamplifier.
  • the magnetic resonance low noise preamplifier of the present invention is designed, manufactured and experimentally tested.
  • the experimental results show that the input impedance of the preamplifier provided by the present invention is 2-3 ohms, the noise figure is 0.46dB, and the gain can reach 27dB.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Amplifiers (AREA)

Abstract

一种前置放大器，包括：输入匹配电路(102)、输入保护电路(101)、放大晶体管(103)、负反馈网络(104)、输出匹配电路(106)、滤波电路(108)以及输出保护电路(107)；放大晶体管(103)通过电阻(R4)与输出匹配电路(106)相连接；输入匹配电路(102)包括：电容(C1)、电容(C2)、电容(C3)以及电感(L1)，电容(C1)、电容(C2)以及电容(C3)的一端均与输入保护电路(101)相连接，电容(C1)的另一端与输入端口相连接，电容(C2)以及电容(C3)并联，电容(C2)、电容(C3)另一端以及电感(L1)的一端连接到放大晶体管(103)的栅极，电感(L1)的另一端接地；负反馈网络(104)的一端连接到放大晶体管(103)的源极，另一端接地，用于调节静态工作点。

Description

一种前置放大器 技术领域
本发明涉及电子技术，具体的讲是一种前置放大器。
背景技术
噪声系数是低噪声放大器最重要的性能指标，因此在输入匹配的设计过程中，一般采用的是噪声匹配，以求能达到最小的噪声系数，而不是输入阻抗匹配到50欧以达到最大的增益。如何权衡噪声系数最小化和增益最大化是一个设计难点。
1H原子在磁共振系统里产生的信号是微伏量级的，必须要经过放大后才能进行后处理。为了减小信号的衰减，通常是把低噪声前置放大器集成到接收线圈中。低噪声前置放大器的性能，直接影响图像的信噪比。因此，对于低噪声前置放大器的设计要求是在保证足够大的增益时要有较低的噪声系数，以获取较高的图像信噪比。
发明内容
本发明实施例提供了一种前置放大器，包括：输入匹配电路、输入保护电路、放大晶体管、负反馈网络、输出匹配电路、滤波电路以及输出保护电路；所述的放大晶体管通过电阻(R4)与输出匹配电路相连接；其中，
所述的输入匹配电路包括：电容(C1)、电容(C2)、电容(C3)以及电感(L1)，电容(C1)、电容(C2)以及电容(C3)的一端均与输入保护电路相连接，电容(C1)的另一端与输入端口相连接，电容(C2)以及电容(C3)并联，电容(C2)、电容(C3)另一端以及电感(L1)的一端连接到放大晶体管的栅极，电感(L1)的另一端接地；
所述的负反馈网络的一端连接到放大晶体管的源极，另一端接地，用于调节静态工作点。
本申请实施例中，所述的放大晶体管为砷化镓增强型伪形态高电子迁移率晶体管。
本申请实施例中，所述的负反馈网络包括：第一反馈单元和第二反馈单元，两反馈单元的一端与放大晶体管的源极连接，另一端接地；其中，
所述第一反馈单元包括：电容(C5)、电容(C4)以及电阻(Rs1)，电阻(Rs1)一端接地，另一端与放大晶体管的源极连接，所述电容(C5)、电容(C4)与电阻(Rs1)并联连接；
所述第二反馈单元包括：电容(C6)、电容(C7)以及电阻(Rs2)，电阻(Rs2)一端接地，另一端与放大晶体管的源极连接，所述电容(C6)、电容(C7)与电阻(Rs2)并联连接。
本申请实施例中，所述的放大器还包括：稳流电路，所述稳流电路通过电阻(R1)连接到放大晶体管的漏极，通过电阻(R4)连接到输出匹配电路。
本申请实施例中，所述的稳流电路包括：双极结型晶体管、电阻(R2)，电阻(R3)、电容(C8)以及电容(C9)；
双极结型晶体管的发射极通过电阻(R1)连接到放大晶体管的漏极，双极结型晶体管的集电极通过电阻(R4)连接到输出匹配电路；
电阻(R2)、电容(C8)以及电容(C9)的一端均连接到双极结型晶体管的基极，电阻(R2)、电容(C8)以及电容(C9)的另一端接地，电阻(R3)的一端连接到双极结型晶体管的发射极，另一端与电阻(R2)连接。
本申请提供了一种磁共振低噪声前置放大器，采用一个砷化镓增强型伪形态高电子迁移率晶体管进行单级放大，降低电路的复杂度和成本，并在电路中采用了负反馈网络，增加了稳流电路模块，提高前置放大器的工作稳定性，适用于较为常用的临床磁共振系统。
为让本发明的上述和其他目的、特征和优点能更明显易懂，下文特举较佳实施例，并配合所附图式，作详细说明如下。
附图说明
为了更清楚地说明本发明实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1为本发明实施例中的前置放大器的结构框图；
图2为本申请实施例中的前置放大器的电路图。
具体实施方式
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
本发明实施例提供一种磁共振低噪声前置放大器，采用一个砷化镓增强型伪形态高电子迁移率晶体管进行单级放大，其电路包括：输入保护电路、输入匹配电路、放大晶体管、负反馈网络、稳流电路、输出匹配电路、输出保护电路、滤波电路，本申请实施例中，通过反复调试实际电路中输入阻抗网络的数值，使得输入阻抗为2-3欧，最终测得噪声系数为0.46dB，增益可达到27dB，实现了噪声系数最小化和增益最大化的平衡。
如图1所述，为本发明实施例中的前置放大器的结构框图，其包括：输入保护电路101、输入匹配电路102、放大晶体管103、负反馈网络104、稳流电路105、输出匹配电路106、输出保护电路107、滤波电路108。本申请实施例中，放大晶体管103采用了一个砷化镓增强型伪形态高电子迁移率晶体管进行单级放大，降低电路的复杂度和成本；采用了负反馈网络104和增加了稳流电路105，提高了前置放大器的工作稳定性；适用于高场磁共振系统。
本发明实施例中，如图2所示，为本申请实施例中的前置放大器的电路图，电路系统包括：输入保护电路201、输入匹配电路202、负反馈网络203、放大晶体管204、稳流电路205、输出匹配电路206、输出保护电路207、滤波电路208。
本发明实施例中，放大晶体管采用一个砷化镓增强型伪形态高电子迁移率晶体管，型号为ATF-38143，进行单级放大；对于该放大晶体管的静态工作点选取，参考了该晶体管产品数据表中的标准值，并在软件ADS中进行了仿真；基于以上静态工作点的分析，对于该放大晶体管偏置电路设计，采用了负反馈偏置的方式。
本发明实施例中，输入保护电路采用了一个二极管对来实现，防止信号过大烧坏放大晶体管。
本发明实施例中，电容C1、C2、C3和电感L1是放大晶体管输入端的匹配网络，其中电感采用高品质因子无磁空心电感，主要通过微调电容C3的容值，来实现噪声系数和输入阻抗的优化。
本发明实施例中，负反馈偏置网络由电容C4、C5、电阻Rs1和电容C6、C7、电阻Rs2组成，由Rs1和Rs2源极负反馈得到反向电压，静态工作点主要通过调节电阻Rs1、Rs2和R1、R4来进行调节，得到稳定的增益和良好的线性度。
本发明实施例中，稳流电路包括一个双极结型晶体管、电阻R2、R3和电容C8、C9，在电路中起到一个电流追随器的作用，保证供电电流的稳定性。
本发明实施例中，放大晶体管输出端的匹配网络由电容C10、C11、C12和电感L2组成，在实际调试中，主要通过微调电容C10的大小来实现输出阻抗的匹配。
本发明实施例中，由于本发明的电路结构输入和电源供电共用一根线，为了把信号和供电分开，在电路中加入了电感L3和电容C13、C14，起到了滤波作用。
本发明实施例中，输出端保护电路采用了两个二极管对串联来实现，在信号过大的情况下，对放大晶体管起到保护作用。
本发明的磁共振低噪声前置放大器，放大晶体管采用一个砷化镓增强型伪形态高电子迁移率晶体管进行单级放大，降低电路的复杂度和成本；在电路中采用了负反馈网络和增加了稳流电路模块，提高了前置放大器的工作稳定性。
本申请实施例中的前置放大器相对于现有技术的二级放大结构低噪声前置放大器，电路相对简单，降低了成本；采用了负反馈方式和增加了稳流电路，提高了前置放大器工作的稳定性；通过电路参数的合理设计，实现了噪声系数最小化和增益最大化的平衡；适用于高场磁共振系统。
对本发明的磁共振低噪声前置放大器进行了设计、制作和实验测试，实验结果表明本发明提供的前置放大器的输入阻抗为2-3欧，噪声系数为0.46dB，增益可达到27dB。
本发明中应用了具体实施例对本发明的原理及实施方式进行了阐述，以上实施例的说明只是用于帮助理解本发明的方法及其核心思想；同时，对于本领域的一般技术人员，依据本发明的思想，在具体实施方式及应用范围上均会有改变之处，综上所述，本说明书内容不应理解为对本发明的限制。

Claims (5)

  1. 一种前置放大器，所述的放大器包括：输入匹配电路、输入保护电路、放大晶体管、负反馈网络、输出匹配电路、滤波电路以及输出保护电路；所述的放大晶体管通过电阻(R4)与输出匹配电路相连接；其中，
    所述的输入匹配电路包括：电容(C1)、电容(C2)、电容(C3)以及电感(L1)，电容(C1)、电容(C2)以及电容(C3)的一端均与输入保护电路相连接，电容(C1)的另一端与输入端口相连接，电容(C2)以及电容(C3)并联，电容(C2)、电容(C3)另一端以及电感(L1)的一端连接到放大晶体管的栅极，电感(L1)的另一端接地；
    所述的负反馈网络的一端连接到放大晶体管的源极，另一端接地，用于调节静态工作点。
  2. 如权利要求1所述的前置放大器，所述的放大晶体管为砷化镓增强型伪形态高电子迁移率晶体管。
  3. 如权利要求1或2所述的前置放大器，所述的负反馈网络包括：第一反馈单元和第二反馈单元，两反馈单元的一端与放大晶体管的源极连接，另一端接地；其中，
    所述第一反馈单元包括：电容(C5)、电容(C4)以及电阻(Rs1)，电阻(Rs1)一端接地，另一端与放大晶体管的源极连接，所述电容(C5)、电容(C4)与电阻(Rs1)并联连接；
    所述第二反馈单元包括：电容(C6)、电容(C7)以及电阻(Rs2)，电阻(Rs2)一端接地，另一端与放大晶体管的源极连接，所述电容(C6)、电容(C7)与电阻(Rs2)并联连接。
  4. 如权利要求1所述的前置放大器，所述的放大器还包括：稳流电路，所述稳流电路通过电阻(R1)连接到放大晶体管的漏极，通过电阻(R4)连接到输出匹配电路。
  5. 如权利要求4所述的前置放大器，其特征在于，所述的稳流电路包括：双极结型晶体管、电阻(R2)，电阻(R3)、电容(C8)以及电容(C9)；
    双极结型晶体管的发射极通过电阻(R1)连接到放大晶体管的漏极，双极结型晶体管的集电极通过电阻(R4)连接到输出匹配电路；
    电阻(R2)、电容(C8)以及电容(C9)的一端均连接到双极结型晶体管的基极，电阻(R2)、电容(C8)以及电容(C9)的另一端接地，电阻(R3)的一端连接到双极结型晶体管的发射极，另一端与电阻(R2)连接。
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101789761A (zh) * 2010-02-02 2010-07-28 杭州电子科技大学 一种电容负反馈形式的低噪声放大器
CN201541238U (zh) * 2009-09-11 2010-08-04 清华大学 一种能降低低频噪声的磁共振成像mri系统前置放大器
CN102664595A (zh) * 2011-12-12 2012-09-12 中国科学院深圳先进技术研究院 前置放大器及磁共振放大装置
US20170104461A1 (en) * 2013-07-03 2017-04-13 Avnera Corporation On-chip resistor divider compensation with a 2vrms input

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN201541238U (zh) * 2009-09-11 2010-08-04 清华大学 一种能降低低频噪声的磁共振成像mri系统前置放大器
CN101789761A (zh) * 2010-02-02 2010-07-28 杭州电子科技大学 一种电容负反馈形式的低噪声放大器
CN102664595A (zh) * 2011-12-12 2012-09-12 中国科学院深圳先进技术研究院 前置放大器及磁共振放大装置
US20170104461A1 (en) * 2013-07-03 2017-04-13 Avnera Corporation On-chip resistor divider compensation with a 2vrms input

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