An amplifier for an electro-hydraulic servo valve

Abstract

The application provides an amplifier for an electro-hydraulic servo valve, comprising a first MOS tube M1, a second MOS tube M2, a third MOS tube M3, a fourth MOS tube M4, a fifth MOS tube M5, a sixth MOS tube M6, a seventh MOS tube M7, an eighth MOS tube M8, a ninth MOS tube M9, a tenth MOS tube M10, an eleventh MOS tube M11, a twelfth MOS tube M12, a thirteenth MOS tube M13, a fourteenth MOS tube M14, a fifteenth MOS tube M15, a first resistor R1, a second resistor R2, a bias current source Ibias and an output capacitor Cout. The application can improve stability, increase amplification gain and avoid external interference.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electro-hydraulic control, in particular to an amplifier for an electro-hydraulic servo valve. BACKGROUND

[0002] With the rapid development of electro-hydraulic servo control technology, the electro-hydraulic servo control system has the advantages of high control precision, fast response speed, and large load rigidity, and is gradually widely used in the fields of ships, aviation, aerospace, etc. Among them, the electro-hydraulic servo valve as the core element of the electro-hydraulic servo control system can control the output of high-power hydraulic energy through small-power electrical signals, and plays a key role in the static and dynamic characteristics of the system.

[0003] The actual electro-hydraulic servo valve control usually adopts negative feedback technology, uses a sensor to collect a flow signal or a displacement signal to obtain a feedback signal, and compares the feedback signal with a given signal to obtain a deviation signal for controlling the electro-hydraulic servo valve. Since the power of the deviation signal is small, it cannot meet the control requirements and is not enough to drive the electro-hydraulic servo valve to work, so an amplifier needs to be set to amplify the power of the deviation signal for controlling the electro-hydraulic servo valve.

[0004] However, the existing amplifier has the disadvantages of low amplification gain, poor stability, and easy to be disturbed by the outside world, and cannot meet the control requirements of the amplifier in actual engineering, so there is an urgent need for an amplifier with high stability, large enough amplification gain, and not easy to be disturbed by the outside world for controlling the electro-hydraulic servo valve. SUMMARY

[0005] In view of the above problems, the present application is proposed to provide an amplifier for an electro-hydraulic servo valve, which can improve stability, increase amplification gain, and avoid external interference.

[0006] The present application discloses an amplifier for an electro-hydraulic servo valve, comprising a first MOS tube M1, a second MOS tube M2, a third MOS tube M3, a fourth MOS tube M4, a fifth MOS tube M5, a sixth MOS tube M6, a seventh MOS tube M7, an eighth MOS tube M8, a ninth MOS tube M9, a tenth MOS tube M10, an eleventh MOS tube M11, a twelfth MOS tube M12, a thirteenth MOS tube M13, a fourteenth MOS tube M14, a fifteenth MOS tube M15, a first resistor R1, a second resistor R2, a bias current source Ibias, and an output capacitor Cout.

[0007] The power supply end of the bias current source Ibias is connected to the power supply VDD, the current output end of the bias current source Ibias is connected to the drain of the third MOS tube M3, the gate of the third MOS tube M3, the gate of the fourth MOS tube M4, and the gate of the seventh MOS tube M7; the gate of the first MOS tube M1 is the first input end of the amplifier and receives the feedback signal Vfb; the drain of the first MOS tube M1 is connected to the drain of the eighth MOS tube M8; the source of the first MOS tube M1 is connected to the source of the second MOS tube M2 and the drain of the fourth MOS tube M4; the gate of the second MOS tube M2 is the second input end of the amplifier and receives the given signal Vref; the drain of the second MOS tube M2 is connected to the drain of the twelfth MOS tube M12; the sources of the fifth MOS tube M5, the eighth MOS tube M8, and the twelfth MOS tube M12 are connected to the power supply VDD; the gate of the fifth MOS tube M5 is connected to the drain of the sixth MOS tube M6, the gate of the eighth MOS tube M8, the gate of the twelfth MOS tube M12, and the first end of the first resistor R1; the drain of the fifth MOS tube M5 is connected to the source of the sixth MOS tube M6; the gate of the sixth MOS tube M6 is connected to the gate of the ninth MOS tube M9, the gate of the thirteenth MOS tube M13, the second end of the first resistor R1, and the drain of the seventh MOS tube M7; the drain of the eighth MOS tube M8 is connected to the source of the ninth MOS tube M9; the drain of the ninth MOS tube M9 is connected to the first end of the second resistor R2, the gate of the tenth MOS tube M10, and the gate of the fourteenth MOS tube M14; the second end of the second resistor R2 is connected to the drain of the tenth MOS tube M10, the gate of the eleventh MOS tube M11, and the gate of the fifteenth MOS tube M15; the source of the tenth MOS tube M10 is connected to the drain of the eleventh MOS tube M11; the drain of the twelfth MOS tube M12 is connected to the source of the thirteenth MOS tube M13; the drain of the thirteenth MOS tube M13 is connected to the drain of the fourteenth MOS tube M14 and the first end of the output capacitor Cout, and is the output end of the amplifier, generating the amplified signal Vout; the source of the fourteenth MOS tube M14 is connected to the drain of the fifteenth MOS tube M15; the sources of the third MOS tube M3, the fourth MOS tube M4, the seventh MOS tube M7, the eleventh MOS tube M11, the fifteenth MOS tube M15, and the second end of the output capacitor Cout are commonly connected to the reference ground VSS.

[0008] Further, the first MOS tube M1, the second MOS tube M2, the third MOS tube M3, the fourth MOS tube M4, the seventh MOS tube M7, the tenth MOS tube M10, the eleventh MOS tube M11, the fourteenth MOS tube M14, and the fifteenth MOS tube M15 are NMOS tubes. The fifth MOS tube M5, the sixth MOS tube M6, the eighth MOS tube M8, the ninth MOS tube M9, the twelfth MOS tube M12, and the thirteenth MOS tube M13 are PMOS tubes.

[0009] Further, the bias current source Ibias includes a sixteenth MOS transistor M16, a seventeenth MOS transistor M17, an eighteenth MOS transistor M18, a nineteenth MOS transistor M19, a twentieth MOS transistor M20, and a third resistor R3.

[0010] The drain of the sixteenth MOS transistor M16 and the drain of the seventeenth MOS transistor M17 are connected to a power supply VDD as a power supply end of the bias current source Ibias; the gate of the sixteenth MOS transistor M16 is connected to the gate of the seventeenth MOS transistor M17, the source of the sixteenth MOS transistor M16 and the drain of the eighteenth MOS transistor M18; the gate of the eighteenth MOS transistor M18 is connected to the gate of the nineteenth MOS transistor M19, the source of the eighteenth MOS transistor M18, and the drain of the twentieth MOS transistor M20; the gate of the twentieth MOS transistor M20 is connected to the source of the nineteenth MOS transistor M19 and serves as a current output end of the bias current source Ibias; the source of the twentieth MOS transistor M20 is connected to a first end of the third resistor R3; a second end of the third resistor R3 is connected to a reference ground VSS; and the source of the seventeenth MOS transistor M17 is connected to the drain of the nineteenth MOS transistor M19.

[0011] Further, the sixteenth MOS transistor M16, the seventeenth MOS transistor M17, the eighteenth MOS transistor M18, the nineteenth MOS transistor M19, and the twentieth MOS transistor M20 are NMOS transistors.

[0012] The present application has the following advantages:

[0013] (1) The present application provides an amplifier for an electro-hydraulic servo valve, which adopts an NMOS input differential pair transistor to improve the amplification gain and reduce interference, and uses a first resistor R1 and a second resistor R2 to provide a gate voltage for a corresponding current mirror circuit, so as to ensure that the amplifier works in a saturation region and improve the stability of the amplifier.

[0014] (2) In the present application, the output current of the bias current source Ibias can be changed by adjusting the size of the third resistor R3, and two pairs of NMOS transistors are used to form a current mirror circuit, which reduces the influence of temperature change on the circuit and improves the current stability. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort.

[0016] Figure 1A circuit structure diagram of an amplifier for an electro-hydraulic servo valve provided by the present application is shown in the figure.

[0017] Figure 2 Another circuit structure diagram of an amplifier for an electro-hydraulic servo valve provided by the present application is shown in the figure. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0019] The terms used in the embodiments of the present application are only for the purpose of describing the specific embodiments, and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. "Plural" generally includes at least two, but does not exclude the case of including at least one.

[0020] The present application will be further described below with reference to the drawings and specific embodiments.

[0021] Figure 1 An amplifier for an electro-hydraulic servo valve provided by the present application includes a first MOS tube M1, a second MOS tube M2, a third MOS tube M3, a fourth MOS tube M4, a fifth MOS tube M5, a sixth MOS tube M6, a seventh MOS tube M7, an eighth MOS tube M8, a ninth MOS tube M9, a tenth MOS tube M10, an eleventh MOS tube M11, a twelfth MOS tube M12, a thirteenth MOS tube M13, a fourteenth MOS tube M14, a fifteenth MOS tube M15, a first resistor R1, a second resistor R2, a bias current source Ibias and an output capacitor Cout.

[0022] The power supply end of the bias current source Ibias is connected to the power supply VDD, the current output end of the bias current source Ibias is connected to the drain of the third MOS tube M3, the gate of the third MOS tube M3, the gate of the fourth MOS tube M4, and the gate of the seventh MOS tube M7; the gate of the first MOS tube M1 is the first input end of the amplifier and receives the feedback signal Vfb; the drain of the first MOS tube M1 is connected to the drain of the eighth MOS tube M8; the source of the first MOS tube M1 is connected to the source of the second MOS tube M2 and the drain of the fourth MOS tube M4; the gate of the second MOS tube M2 is the second input end of the amplifier and receives the given signal Vref; the drain of the second MOS tube M2 is connected to the drain of the twelfth MOS tube M12; the sources of the fifth MOS tube M5, the eighth MOS tube M8, and the twelfth MOS tube M12 are connected to the power supply VDD; the gate of the fifth MOS tube M5 is connected to the drain of the sixth MOS tube M6, the gate of the eighth MOS tube M8, the gate of the twelfth MOS tube M12, and the first end of the first resistor R1; the drain of the fifth MOS tube M5 is connected to the source of the sixth MOS tube M6; the gate of the sixth MOS tube M6 is connected to the gate of the ninth MOS tube M9, the gate of the thirteenth MOS tube M13, the second end of the first resistor R1, and the drain of the seventh MOS tube M7; the drain of the eighth MOS tube M8 is connected to the source of the ninth MOS tube M9; the drain of the ninth MOS tube M9 is connected to the first end of the second resistor R2, the gate of the tenth MOS tube M10, and the gate of the fourteenth MOS tube M14; the second end of the second resistor R2 is connected to the drain of the tenth MOS tube M10, the gate of the eleventh MOS tube M11, and the gate of the fifteenth MOS tube M15; the source of the tenth MOS tube M10 is connected to the drain of the eleventh MOS tube M11; the drain of the twelfth MOS tube M12 is connected to the source of the thirteenth MOS tube M13; the drain of the thirteenth MOS tube M13 is connected to the drain of the fourteenth MOS tube M14 and the first end of the output capacitor Cout, and is the output end of the amplifier, generating the amplified signal Vout; the source of the fourteenth MOS tube M14 is connected to the drain of the fifteenth MOS tube M15; the sources of the third MOS tube M3, the fourth MOS tube M4, the seventh MOS tube M7, the eleventh MOS tube M11, the fifteenth MOS tube M15, and the second end of the output capacitor Cout are commonly connected to the reference ground VSS.

[0023] Further, the first MOS tube M1, the second MOS tube M2, the third MOS tube M3, the fourth MOS tube M4, the seventh MOS tube M7, the tenth MOS tube M10, the eleventh MOS tube M11, the fourteenth MOS tube M14, and the fifteenth MOS tube M15 are NMOS tubes; the fifth MOS tube M5, the sixth MOS tube M6, the eighth MOS tube M8, the ninth MOS tube M9, the twelfth MOS tube M12, and the thirteenth MOS tube M13 are PMOS tubes.

[0024] In the amplifier, the first MOS transistor M1 and the second MOS transistor M2 constitute an NMOS input differential pair transistor, and the noise signal is suppressed by amplifying the difference between the feedback signal Vfb and the given signal Vref, so that the amplifier has strong anti-interference ability and improved stability performance. Meanwhile, the NMOS input differential pair transistor has greater amplification gain than the PMOS input differential pair transistor, so that the amplification gain of the amplifier is also improved.

[0025] The third MOS transistor M3, the fourth MOS transistor M4, the fifth MOS transistor M5, the sixth MOS transistor M6, the seventh MOS transistor M7, the eighth MOS transistor M8, the ninth MOS transistor M9, the twelfth MOS transistor M12 and the thirteenth MOS transistor M13 form a plurality of groups of current mirror circuits, which are used to provide static working current for the amplifier.

[0026] The current mirror current formed by the third MOS transistor M3 and the seventh MOS transistor M7 passes through the first resistor R1, and the voltage difference across the first resistor R1 is used to form two gate voltages, which are used to drive the gates of the eighth MOS transistor M8 and the twelfth MOS transistor M12, and the gates of the ninth MOS transistor M9 and the thirteenth MOS transistor M13, so as to ensure that the eighth MOS transistor M8 and the twelfth MOS transistor M12, and the ninth MOS transistor M9 and the thirteenth MOS transistor M13 work in the saturation region, thereby improving the stability performance of the amplifier.

[0027] The tenth MOS transistor M10 and the fourteenth MOS transistor M14, and the eleventh MOS transistor M11 and the fifteenth MOS transistor M15 respectively constitute two groups of basic current mirror circuits, and the two groups of basic current mirror circuits are cascaded to convert the double-ended output of the amplifier into a single-ended output, so as to form an amplification voltage Vout at the drain of the thirteenth MOS transistor M13 and the drain of the fourteenth MOS transistor M14, while increasing the output impedance and improving the circuit gain, thereby realizing an amplifier with high amplification gain.

[0028] The tenth MOS transistor M10 is in a diode connection structure, and the voltage across the second resistor R2 is used to provide gate voltages for the tenth MOS transistor M10 and the fourteenth MOS transistor M14, and the eleventh MOS transistor M11 and the fifteenth MOS transistor M15, so as to ensure that the tenth MOS transistor M10 and the fourteenth MOS transistor M14, and the eleventh MOS transistor M11 and the fifteenth MOS transistor M15 work in the saturation region, and to suppress the influence of the channel length modulation effect on the current mirror image current, thereby improving the stability performance of the amplifier.

[0029] In another embodiment of the present application, as shown in Figure 2 the bias current source Ibias of the amplifier includes a sixteenth MOS transistor M16, a seventeenth MOS transistor M17, an eighteenth MOS transistor M18, a nineteenth MOS transistor M19, a twentieth MOS transistor M20 and a third resistor R3.

[0030] The drain of the sixteenth MOS transistor M16 and the drain of the seventeenth MOS transistor M17 are connected to the power supply VDD as the power supply end of the bias current source Ibias; the gate of the sixteenth MOS transistor M16 is connected to the gate of the seventeenth MOS transistor M17, the source of the sixteenth MOS transistor M16 and the drain of the eighteenth MOS transistor M18; the gate of the eighteenth MOS transistor M18 is connected to the gate of the nineteenth MOS transistor M19, the source of the eighteenth MOS transistor M18 and the drain of the twentieth MOS transistor M20; the gate of the twentieth MOS transistor M20 is connected to the source of the nineteenth MOS transistor M19 and serves as the current output end of the bias current source Ibias; the source of the twentieth MOS transistor M20 is connected to the first end of the third resistor R3; the second end of the third resistor R3 is connected to the reference ground VSS; and the source of the seventeenth MOS transistor M17 is connected to the drain of the nineteenth MOS transistor M19.

[0031] Further, the sixteenth MOS transistor M16, the seventeenth MOS transistor M17, the eighteenth MOS transistor M18, the nineteenth MOS transistor M19 and the twentieth MOS transistor M20 are NMOS transistors.

[0032] The bias current source Ibias of the amplifier can change the output current of the bias current source Ibias by adjusting the size of the third resistor R3, and the current mirror circuit is formed by two pairs of NMOS transistors, which reduces the influence of temperature change on the circuit and improves the current stability.

[0033] The above description shows and describes several preferred embodiments of the present application, but as mentioned above, it should be understood that the present application is not limited to the forms disclosed herein, and should not be considered as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the inventive concept described herein by the above teaching or related art or knowledge. Any modification and change made by those skilled in the art without departing from the spirit and scope of the present application shall be within the protection scope of the appended claims of the present application.

Claims

1. An amplifier for an electro-hydraulic servo valve, characterized by The first MOS transistor M1, the second MOS transistor M2, the third MOS transistor M3, the fourth MOS transistor M4, the fifth MOS transistor M5, the sixth MOS transistor M6, the seventh MOS transistor M7, the eighth MOS transistor M8, the ninth MOS transistor M9, the tenth MOS transistor M10, the eleventh MOS transistor M11, the twelfth MOS transistor M12, the thirteenth MOS transistor M13, the fourteenth MOS transistor M14, the fifteenth MOS transistor M15, the first resistor R1, the second resistor R2, the bias current source Ibias and the output capacitor Cout are included. The power supply end of the bias current source Ibias is connected to the power supply VDD, the current output end of the bias current source Ibias is connected to the drain of the third MOS transistor M3, the gate of the third MOS transistor M3, the gate of the fourth MOS transistor M4 and the gate of the seventh MOS transistor M7; the gate of the first MOS transistor M1 is the first input end of the amplifier and receives the feedback signal Vfb; the drain of the first MOS transistor M1 is connected to the drain of the eighth MOS transistor M8; the source of the first MOS transistor M1 is connected to the source of the second MOS transistor M2 and the drain of the fourth MOS transistor M4; the gate of the second MOS transistor M2 is the second input end of the amplifier and receives the given signal Vref; the drain of the second MOS transistor M2 is connected to the drain of the twelfth MOS transistor M12; the sources of the fifth MOS transistor M5, the eighth MOS transistor M8 and the twelfth MOS transistor M12 are connected to the power supply VDD; the gate of the fifth MOS transistor M5 is connected to the drain of the sixth MOS transistor M6, the gate of the eighth MOS transistor M8, the gate of the twelfth MOS transistor M12 and the first end of the first resistor R1; the drain of the fifth MOS transistor M5 is connected to the source of the sixth MOS transistor M6; the gate of the sixth MOS transistor M6 is connected to the gate of the ninth MOS transistor M9, the gate of the thirteenth MOS transistor M13, the second end of the first resistor R1 and the drain of the seventh MOS transistor M7; the drain of the eighth MOS transistor M8 is connected to the source of the ninth MOS transistor M9; the drain of the ninth MOS transistor M9 is connected to the first end of the second resistor R2, the gate of the tenth MOS transistor M10 and the gate of the fourteenth MOS transistor M14; the second end of the second resistor R2 is connected to the drain of the tenth MOS transistor M10, the gate of the eleventh MOS transistor M11 and the gate of the fifteenth MOS transistor M15; the source of the tenth MOS transistor M10 is connected to the drain of the eleventh MOS transistor M11; the drain of the twelfth MOS transistor M12 is connected to the source of the thirteenth MOS transistor M13; the drain of the thirteenth MOS transistor M13 is connected to the drain of the fourteenth MOS transistor M14 and the first end of the output capacitor Cout and is the output end of the amplifier to generate the amplified signal Vout; the source of the fourteenth MOS transistor M14 is connected to the drain of the fifteenth MOS transistor M15; the sources of the third MOS transistor M3, the fourth MOS transistor M4, the seventh MOS transistor M7, the eleventh MOS transistor M11, the fifteenth MOS transistor M15 and the second end of the output capacitor Cout are commonly connected to the reference ground VSS.

2. The amplifier of claim 1, wherein, The first MOS transistor M1, the second MOS transistor M2, the third MOS transistor M3, the fourth MOS transistor M4, the seventh MOS transistor M7, the tenth MOS transistor M10, the eleventh MOS transistor M11, the fourteenth MOS transistor M14 and the fifteenth MOS transistor M15 are NMOS transistors; the fifth MOS transistor M5, the sixth MOS transistor M6, the eighth MOS transistor M8, the ninth MOS transistor M9, the twelfth MOS transistor M12 and the thirteenth MOS transistor M13 are PMOS transistors.

3. The amplifier of claim 2, wherein, The bias current source Ibias includes a sixteenth MOS transistor M16, a seventeenth MOS transistor M17, an eighteenth MOS transistor M18, a nineteenth MOS transistor M19, a twentieth MOS transistor M20 and a third resistor R3. The drain of the sixteenth MOS transistor M16 and the drain of the seventeenth MOS transistor M17 are connected to the power supply VDD as the power supply end of the bias current source Ibias; the gate of the sixteenth MOS transistor M16 is connected to the gate of the seventeenth MOS transistor M17, the source of the sixteenth MOS transistor M16 and the drain of the eighteenth MOS transistor M18; the gate of the eighteenth MOS transistor M18 is connected to the gate of the nineteenth MOS transistor M19, the source of the eighteenth MOS transistor M18 and the drain of the twentieth MOS transistor M20; the gate of the twentieth MOS transistor M20 is connected to the source of the nineteenth MOS transistor M19 and serves as the current output end of the bias current source Ibias; the source of the twentieth MOS transistor M20 is connected to the first end of the third resistor R3; the second end of the third resistor R3 is connected to the reference ground VSS; and the source of the seventeenth MOS transistor M17 is connected to the drain of the nineteenth MOS transistor M19.

4. The amplifier of claim 3, wherein, The sixteenth MOS transistor M16, the seventeenth MOS transistor M17, the eighteenth MOS transistor M18, the nineteenth MOS transistor M19 and the twentieth MOS transistor M20 are NMOS transistors.

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