CN217032618U - Floating differential amplification system for sensor signals - Google Patents
Floating differential amplification system for sensor signals Download PDFInfo
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- CN217032618U CN217032618U CN202220865892.1U CN202220865892U CN217032618U CN 217032618 U CN217032618 U CN 217032618U CN 202220865892 U CN202220865892 U CN 202220865892U CN 217032618 U CN217032618 U CN 217032618U
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Abstract
The utility model provides a floating differential amplification system for sensor signals, and belongs to the technical field of sensor signal processing. The floating differential amplification system comprises a pre-amplification unit and a main amplification unit which are sequentially connected between the output side of the voltage output type sensor and the input side of the differential analog-to-digital converter. The pre-amplification unit is a fully differential bootstrap following amplification circuit with the input and the output both in a floating mode, and the main amplification unit is a fully differential amplification circuit with the input and the output both in a floating mode. According to the utility model, the problem that the reliability and stability of the self-measurement of the existing electromagnetic flow sensor are influenced by the arrangement of the grounding piece can be solved.
Description
Technical Field
The utility model belongs to the technical field of sensor signal processing, and particularly relates to a floating differential amplification system for a sensor signal.
Background
An electromagnetic flowmeter is an instrument which measures the flow of a conductive fluid according to the electromotive force induced when the conductive fluid passes through an external magnetic field by applying the electromagnetic induction principle. The existing electromagnetic flowmeter mainly comprises an electromagnetic flow sensor and an electromagnetic flow converter. The electromagnetic flow sensor is designed according to Faraday's law of electromagnetic induction, a pair of detection electrodes are mounted on the wall of the measuring tube, the axis of the measuring tube is perpendicular to the magnetic lines of force of a magnetic field, when the conductive liquid moves along the measuring tube in the direction perpendicular to the magnetic lines of force in an alternating magnetic field, the conductive liquid cuts the magnetic lines of force to generate induced electromotive force, and the induced electromotive force is detected by the two detection electrodes on the measuring tube and is output in the form of differential voltage signals. The electromagnetic flow converter can be divided into a signal processing circuit and an analog-to-digital conversion circuit, the signal processing circuit is mainly used for amplifying differential voltage signals output by the electromagnetic flow sensor, improving the signal-to-noise ratio and extracting useful signal components, and the analog-to-digital conversion circuit is used for converting processed voltage signals output by the signal processing circuit from analog signals into digital signals.
The differential output voltage signal of the existing electromagnetic flow sensor is obtained by the following steps: and taking the conductive liquid as a reference ground, and performing resistance voltage division on a voltage difference between the two detection electrodes in proportion to the flow velocity of the conductive fluid through the two detection electrodes to form a differential voltage signal and outputting the differential voltage signal to a signal processing circuit. It follows that the stability and reliability of the reference ground potential in contact with the conductive fluid is critical to the detection accuracy of the electromagnetic flow sensor. Therefore, in practical applications, grounding pieces are usually provided at both ends of the measuring pipe of the electromagnetic flowmeter to obtain a stable and reliable reference ground potential. However, since the reliability and stability of the grounding member itself cannot be ensured, the manner of obtaining the reference ground potential by providing the grounding member may adversely affect the measurement of the electromagnetic flow sensor.
SUMMERY OF THE UTILITY MODEL
The utility model aims to solve the problem that the reliability and stability of the self-measurement of the existing electromagnetic flow sensor are influenced by the arrangement of a grounding piece.
In order to achieve the above object, the present invention provides a floating differential amplification system for a sensor signal, including a pre-amplification unit and a main amplification unit sequentially connected between an output side of a voltage output type sensor and an input side of a differential analog-to-digital converter, where the pre-amplification unit is a fully differential bootstrap following amplification circuit whose input and output are both in a floating mode, and the main amplification unit is a fully differential amplification circuit whose input and output are both in a floating mode.
Optionally, the pre-amplification unit includes a first bootstrap following amplification circuit and a second bootstrap following amplification circuit;
the positive potential input end of the first bootstrap follow-up amplifying circuit is connected with the positive potential output end of the voltage output type sensor, the reference potential input end of the first bootstrap follow-up amplifying circuit is connected with a power ground, and the positive potential output end of the first bootstrap follow-up amplifying circuit is connected with the positive potential input end of the main amplifying unit;
the negative potential input end of the second bootstrap following amplifying circuit is connected with the negative potential output end of the voltage output type sensor, the reference potential input end of the second bootstrap following amplifying circuit is connected to the power ground, and the negative potential output end of the second bootstrap following amplifying circuit is connected with the negative potential input end of the main amplifying unit.
Optionally, the first bootstrap follower amplifying circuit includes a resistor R1, a resistor R2, a resistor R3, a resistor R4, a capacitor C1, a capacitor C3, and an operational amplifier U1;
a first end of the capacitor C1 is a positive potential input end of the first bootstrap follower amplifying circuit, and a second end of the capacitor C1 is connected to a non-inverting input end of the operational amplifier U1 and a first end of the resistor R1;
the second end of the resistor R1 is connected with the first end of the resistor R2 and the first end of the resistor R3;
a second end of the resistor R2 is a reference potential input end of the first bootstrap following amplifying circuit;
the second end of the resistor R3 is connected with the inverting input end of the operational amplifier U1, the first end of the resistor R4 and the first end of the capacitor C3 at the same time;
the common end of the output end of the operational amplifier U1, the second end of the resistor R4 and the second end of the capacitor C3 is a positive potential output end of the first bootstrap following amplifying circuit.
Optionally, the second bootstrap follower amplification circuit includes a resistor R5, a resistor R6, a resistor R7, a resistor R8, a capacitor C2, a capacitor C4, and an operational amplifier U2;
a first end of the capacitor C2 is a negative potential input end of the second bootstrap following amplifying circuit, and a second end of the capacitor C2 is connected to a non-inverting input end of the operational amplifier U2 and a first end of the resistor R5;
the second end of the resistor R5 is connected with the first end of the resistor R6 and the first end of the resistor R7;
a second end of the resistor R6 is a reference potential input end of the second bootstrap following amplifying circuit;
the second end of the resistor R7 is connected with the inverting input end of the operational amplifier U2, the first end of the resistor R8 and the first end of the capacitor C4 at the same time;
the common end of the output end of the operational amplifier U2, the second end of the resistor R8 and the second end of the capacitor C4 is a negative potential output end of the second bootstrap following amplifying circuit.
Optionally, the preamplifier unit further includes a resistor R9;
the second end of the resistor R2 and the common end of the second end of the resistor R6 are connected to a protective ground through the resistor R9.
Optionally, the main amplifying unit includes a first amplifying circuit and a second amplifying circuit;
a positive potential input end of the first amplifying circuit is a positive potential input end of the main amplifying unit, a reference potential input end of the first amplifying circuit is connected to the power ground, and a positive potential output end of the first amplifying circuit is connected with a positive potential input end of the differential analog-to-digital converter;
the negative potential input end of the second amplifying circuit is the negative potential input end of the main amplifying unit, the reference potential input end of the second amplifying circuit is connected to the power ground, and the negative potential output end of the second amplifying circuit is connected with the negative potential input end of the differential analog-to-digital converter.
Optionally, the first amplifying circuit includes a resistor R10, a resistor R11, a capacitor C5, and an operational amplifier U3;
a first end of the resistor R10 is a positive potential input end of the first amplifying circuit, and a second end of the resistor R10 is connected to a first end of the resistor R11, a first end of the capacitor C5 and an inverting input end of the operational amplifier U3;
the non-inverting input end of the operational amplifier U3 is the reference potential input end of the first amplifying circuit;
the common end of the second end of the resistor R11, the second end of the capacitor C5 and the output end of the operational amplifier U3 is the positive potential output end of the first amplifying circuit.
Optionally, the second amplifying circuit includes a resistor R12, a resistor R13, a capacitor C6, and an operational amplifier U4;
a first end of the resistor R12 is a negative potential input end of the second amplifying circuit, and a second end of the resistor R12 is connected to an inverting input end of the operational amplifier U4, a first end of the resistor R13 and a first end of the capacitor C6;
the non-inverting input end of the operational amplifier U4 is the reference potential input end of the second amplifying circuit;
the common end of the output end of the operational amplifier U4, the second end of the resistor R13 and the second end of the capacitor C6 is a negative potential output end of the second amplifying circuit.
Optionally, the differential analog-to-digital converter includes an analog-to-digital converter chip U5, a capacitor C7, and a capacitor C8;
the common end of the first end of the capacitor C7 and the positive potential input pin of the analog-to-digital converter chip U5 is the positive potential input end of the differential analog-to-digital converter;
the first end of the capacitor C8 and the common end of the negative potential input pin of the analog-to-digital converter chip U5 are the negative potential input end of the differential analog-to-digital converter;
the second end of the capacitor C7 and the common end of the second end of the capacitor C8 are connected to the power ground.
Optionally, the voltage output type sensor is an electromagnetic flow sensor.
The utility model has the beneficial effects that:
the floating differential amplification system for the sensor signal comprises a pre-amplification unit and a main amplification unit. The pre-amplification unit is a fully differential bootstrap following amplification circuit with the input and the output both in a floating mode, and the main amplification unit is a fully differential amplification circuit with the input and the output both in a floating mode. On one hand, because the pre-amplification unit is a fully differential bootstrap following amplification circuit, the input current of the floating differential amplification system of the sensor signal is almost zero. On the other hand, because the pre-amplification unit is in floating differential input and output, and the main amplification unit is in floating differential input and output, the voltage signal transmission in the floating differential amplification system of the sensor signal of the utility model does not need to use the conductive liquid in the measuring tube of the electromagnetic flow sensor as a reference ground, and only needs to use the power ground as the internal reference potential of the pre-amplification unit and the main amplification unit. For the above two reasons, the electromagnetic flow sensor used with the floating differential amplification system of sensor signals of the present invention does not need to be provided with grounding pieces at two ends of the measuring tube.
According to the above, the floating differential amplification system for sensor signals can effectively solve the problem that the reliability and stability of the existing electromagnetic flow sensor are influenced by the arrangement of the grounding piece.
Additional features and advantages of the utility model will be set forth in the detailed description which follows.
Drawings
The utility model may be better understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like or similar parts throughout the figures.
FIG. 1 shows a block diagram of a floating differential amplification system for a sensor signal according to an embodiment of the utility model;
FIG. 2 illustrates a schematic block circuit diagram of a floating differential amplification system for sensor signals, according to an embodiment of the present invention;
fig. 3 shows a circuit schematic of a floating differential amplification system for a sensor signal according to an embodiment of the utility model.
Detailed Description
In order that those skilled in the art will more fully understand the technical aspects of the present invention, exemplary embodiments of the present invention will be described more fully hereinafter with reference to the accompanying drawings. Obviously, the one or more embodiments of the present invention described below are only one or more of specific ways capable of implementing the technical solutions of the present invention, and are not exhaustive. It should be understood that the technical solution of the present invention can be implemented in other ways belonging to one general inventive concept, and should not be limited by the exemplary described embodiments. All other embodiments, which can be derived by a person skilled in the art from one or more of the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.
The embodiment is as follows: fig. 1 shows a block diagram of a floating differential amplification system of a sensor signal according to an embodiment of the present invention. Referring to fig. 1, the floating differential amplification system for sensor signals according to the embodiment of the present invention includes a pre-amplification unit and a main amplification unit, which are sequentially connected between an output side of a voltage output type sensor and an input side of a differential analog-to-digital converter, where the pre-amplification unit is a fully differential bootstrap following amplification circuit whose input and output are both in a floating mode, and the main amplification unit is a fully differential amplification circuit whose input and output are both in a floating mode.
Further, fig. 2 shows a schematic block circuit diagram of a floating differential amplification system of a sensor signal according to an embodiment of the present invention. Referring to fig. 1 and 2, in the embodiment of the present invention, the pre-amplification unit includes a first bootstrap following amplification circuit and a second bootstrap following amplification circuit;
the positive potential input end of the first bootstrap follow-up amplifying circuit is connected with the positive potential output end of the voltage output type sensor, the reference potential input end of the first bootstrap follow-up amplifying circuit is connected with a power ground, and the positive potential output end of the first bootstrap follow-up amplifying circuit is connected with the positive potential input end of the main amplifying unit;
the negative potential input end of the second bootstrap follow amplifying circuit is connected with the negative potential output end of the voltage output type sensor, the reference potential input end of the second bootstrap follow amplifying circuit is connected with a power ground, and the negative potential output end of the second bootstrap follow amplifying circuit is connected with the negative potential input end of the main amplifying unit.
Still further, fig. 3 shows a schematic circuit diagram of a floating differential amplification system for sensor signals according to an embodiment of the present invention. Referring to fig. 2 and 3, in the embodiment of the present invention, the first bootstrap follower amplification circuit includes a resistor R1, a resistor R2, a resistor R3, a resistor R4, a capacitor C1, a capacitor C3, and an operational amplifier U1;
a first end of the capacitor C1 is a positive potential input end of the first bootstrap following amplifying circuit, and a second end of the capacitor C1 is connected with a non-inverting input end of the operational amplifier U1 and a first end of the resistor R1;
the second end of the resistor R1 is connected with the first end of the resistor R2 and the first end of the resistor R3;
a second end of the resistor R2 is a reference potential input end of the first bootstrap following amplifying circuit;
the second end of the resistor R3 is connected with the inverting input end of the operational amplifier U1, the first end of the resistor R4 and the first end of the capacitor C3 at the same time;
the common end of the output end of the operational amplifier U1, the second end of the resistor R4 and the second end of the capacitor C3 is a positive potential output end of the first bootstrap follower amplification circuit.
Still further, referring to fig. 2 and 3, in the embodiment of the present invention, the second bootstrap follower amplifier circuit includes a resistor R5, a resistor R6, a resistor R7, a resistor R8, a capacitor C2, a capacitor C4, and an operational amplifier U2;
a first end of the capacitor C2 is a negative potential input end of the second bootstrap following amplifying circuit, and a second end of the capacitor C2 is connected with a non-inverting input end of the operational amplifier U2 and a first end of the resistor R5;
the second end of the resistor R5 is connected with the first end of the resistor R6 and the first end of the resistor R7;
a second end of the resistor R6 is a reference potential input end of the second bootstrap following amplifying circuit;
the second end of the resistor R7 is connected with the inverting input end of the operational amplifier U2, the first end of the resistor R8 and the first end of the capacitor C4 at the same time;
the common end of the output end of the operational amplifier U2, the second end of the resistor R8 and the second end of the capacitor C4 is a negative potential output end of the second bootstrap following amplifying circuit.
Still further, referring to fig. 3, in the embodiment of the present invention, the preamplifier unit further includes a resistor R9;
the second end of the resistor R2 and the common end of the second end of the resistor R6 are connected to the protective ground through the resistor R9.
Specifically, in the embodiment of the present invention, a common terminal between the second end of the resistor R2 and the second end of the resistor R6 is connected to a PE terminal of the voltage output type sensor through the resistor R9, and the PE terminal is connected to a protected ground.
Specifically, in the embodiment of the present invention, the capacitor C1, the resistor R1, and the resistor R2 form a high-pass filter, and the capacitor C2, the resistor R5, and the resistor R6 also form a high-pass filter; the first bootstrap following amplifying circuit and the second bootstrap following amplifying circuit both adopt bootstrap amplifying designs, and due to bootstrap feedback of the circuits, the input current of the floating differential amplifying system is almost zero, which is equivalent to that the input resistance (the resistance R1 and the resistance R5) is increased by many times. Therefore, even if relatively small coupling capacitances (the capacitance C1 and the capacitance C2) are used, a large high-pass filter time constant can be obtained. Meanwhile, the requirements on the precision and symmetry of the coupling capacitor and the precision and symmetry of the input resistor are greatly reduced.
Still further, referring to fig. 1 and 2, in an embodiment of the present invention, the main amplifying unit includes a first amplifying circuit and a second amplifying circuit;
the positive potential input end of the first amplifying circuit is the positive potential input end of the main amplifying unit, the reference potential input end of the first amplifying circuit is connected with a power ground, and the positive potential output end of the first amplifying circuit is connected with the positive potential input end of the differential analog-to-digital converter;
the negative potential input end of the second amplifying circuit is the negative potential input end of the main amplifying unit, the reference potential input end of the second amplifying circuit is connected with a power ground, and the negative potential output end of the second amplifying circuit is connected with the negative potential input end of the differential analog-to-digital converter.
Still further, referring to fig. 2 and 3, in an embodiment of the present invention, the first amplifying circuit includes a resistor R10, a resistor R11, a capacitor C5, and an operational amplifier U3;
a first end of the resistor R10 is a positive potential input end of the first amplifying circuit, and a second end of the resistor R10 is connected with a first end of the resistor R11, a first end of the capacitor C5 and an inverting input end of the operational amplifier U3;
the non-inverting input end of the operational amplifier U3 is the reference potential input end of the first amplifying circuit;
the common end of the second end of the resistor R11, the second end of the capacitor C5 and the output end of the operational amplifier U3 is a positive potential output end of the first amplifying circuit.
Still further, referring to fig. 2 and 3, in the embodiment of the present invention, the second amplifying circuit includes a resistor R12, a resistor R13, a capacitor C6, and an operational amplifier U4;
a first end of the resistor R12 is a negative potential input end of the second amplifying circuit, and a second end of the resistor R12 is connected with an inverting input end of the operational amplifier U4, a first end of the resistor R13 and a first end of the capacitor C6;
the non-inverting input end of the operational amplifier U4 is the reference potential input end of the second amplifying circuit;
the common end of the output end of the operational amplifier U4, the second end of the resistor R13 and the second end of the capacitor C6 is a negative potential output end of the second amplifying circuit.
Still further, referring to fig. 2 and 3, in the embodiment of the present invention, the differential analog-to-digital converter includes an analog-to-digital converter chip U5, a capacitor C7, and a capacitor C8;
the first end of the capacitor C7 and the common end of the positive potential input pin of the analog-to-digital converter chip U5 are the positive potential input end of the differential analog-to-digital converter;
the first end of the capacitor C8 and the common end of the negative potential input pin of the analog-to-digital converter chip U5 are the negative potential input end of the differential analog-to-digital converter;
the second end of the capacitor C7 and the common end of the second end of the capacitor C8 are connected to a power ground.
Still further, in an embodiment of the present invention, the voltage output type sensor is an electromagnetic flow sensor. In practical application, the floating differential amplification system for sensor signals of the embodiment of the utility model can also process other sensor signals, such as medical bioelectric signals and industrial sensor low-frequency weak signals.
The following describes the circuit principle of the floating differential amplification system for sensor signals according to an embodiment of the present invention in detail:
an electromagnetic flow sensor: two detection electrodes of the electromagnetic flow sensor are respectively an electrode A and an electrode B, and a pair of potential signals acquired by the electrode A and the electrode B are floating voltage signals with the electrode A and the electrode B in opposite phases.
A pre-amplification unit: the gain of the first bootstrap following amplification circuit and the gain of the second bootstrap following amplification circuit are both 1, wherein the first bootstrap following amplification circuit is a path of an in-phase signal, the second bootstrap following amplification circuit is a path of an opposite-phase signal, and the first bootstrap following amplification circuit and the second bootstrap following amplification circuit are jointly used for realizing voltage conversion from a high input internal resistance signal to a low output resistance signal, improving the actual application values of a resistor R1 and a resistor R5 and reducing the tolerance influence of resistance-capacitance parameters;
specifically, the capacitor C1 is a coupling capacitor, and the resistor R1 and the resistor R2 are input resistors, and form a first high-pass filter; the capacitor C2 is a coupling capacitor, and the resistor R5 and the resistor R6 are input resistors, and form a second high-pass filter; the first high-pass filter and the second high-pass filter are used for suppressing low-frequency components and direct-current noise in the input differential voltage signal;
in order to eliminate low frequency components and dc noise in the input differential voltage signal, the capacitance values of the capacitor C1 and the capacitor C2 are usually selected to be large, thus, a leakage phenomenon is easily generated, and therefore, in the related art, a connection method of directly connecting the capacitor C1 to the a electrode and the capacitor C2 to the B electrode is not generally adopted, but the embodiment of the present invention adopts a bootstrap amplifier to solve the problem of the related art, because the operational amplifier U1 and the operational amplifier U2 are in a 'virtual short' state, the input current is almost zero, and the arrangement can amplify the practical application values of the resistor R1 and the resistor R5 by many times, therefore, under the condition that the high-pass filtering time constant is unchanged, the capacitance values of the capacitor C1 and the capacitor C2 can be reduced by many times, therefore, the leakage of the capacitor C1 and the capacitor C2 is avoided to a certain extent, and the influence of the tolerance of the resistance-capacitance element is reduced;
one end of the resistor R9 is connected to a PE terminal of the electromagnetic flow sensor, so that the input common-mode voltage forms a path and has the function of inhibiting common-mode noise; the common mode rejection ratio is an important part of differential amplifiers and floating amplifiers, and the input, output and power supply terminals of the amplifiers (simply, the power supply ground is taken as a reference point) cannot be insulated from the ground, that is, a relatively large insulation resistance exists between the ground and the internal power supply ground. There is always an induced current flow into the isolation resistors creating a voltage drop called the common mode voltage. Resistor R9 is much smaller than the insulation resistance between ground and the internal power ground, and therefore, it can function to reduce the common mode voltage amplitude.
A main amplification unit: the first amplifying circuit is a path of an in-phase signal, the second amplifying circuit is a path of an anti-phase signal, the operational amplifier U3 and the operational amplifier U4 are both anti-phase amplifiers, and the capacitor C5 and the resistor R11, as well as the capacitor C6 and the resistor R13 form a time constant circuit of the low-pass filter, wherein the time constant determines the cut-off frequency of the low-pass filter, and the low-pass filter is used for removing high-frequency components in the signal; the first and second amplification circuits are capable of reducing a common mode voltage in the input signal.
The floating differential amplification system for the sensor signals provided by the embodiment of the utility model has the following beneficial effects:
1. the floating differential input and the floating differential output enable the conductive liquid in the measuring tube of the electromagnetic flow sensor to be free of grounding, namely grounding pieces are not required to be arranged at two ends of the measuring tube, so that the sealing performance of the electromagnetic flow sensor is guaranteed, and the product cost of the electromagnetic flow sensor can be greatly reduced due to the fact that the grounding pieces are made of high-price corrosion-resistant materials (conductive liquid is corrosive) in the related art.
2. The floating differential input and the floating differential output can be directly connected with a common ADC (analog-to-digital converter) on the market without additional adjustment, a precise reference voltage device is not required to be adopted as in the related technology, the use is more convenient and reliable, the circuit cost is reduced, the technical advantages of the integrated ADC device can be fully exerted, the digital quantity and software measurement are utilized to suppress common-mode noise, the measurement precision is improved, and the hardware of the circuit is reduced.
3. In the bootstrap amplification mode, the system input current is almost zero, so that the practical application values (actually generated effects) of the resistor R1 and the resistor R5 can be increased by many times. Under the same high-pass filtering time constant, the capacitance values of the capacitors C1 and C2 can be reduced by corresponding times, and the arrangement can reduce the influence of capacitance leakage and resistance-capacitance element tolerance, thereby meeting the measurement requirement.
Although one or more embodiments of the present invention have been described above, it will be appreciated by those skilled in the art that the present invention can be embodied in any other forms without departing from the spirit or scope thereof. Accordingly, the above-described embodiments are intended to be illustrative, not limiting, and many modifications and alterations may be apparent to those of ordinary skill in the art without departing from the spirit and scope of the utility model, as defined by the following claims.
Claims (10)
1. The floating differential amplification system for the sensor signals comprises a pre-amplification unit and a main amplification unit which are sequentially connected between the output side of a voltage output type sensor and the input side of a differential analog-to-digital converter, and is characterized in that the pre-amplification unit is a fully differential bootstrap following amplification circuit with the input and the output in a floating mode, and the main amplification unit is a fully differential amplification circuit with the input and the output in the floating mode.
2. The floating differential amplification system of claim 1, wherein the pre-amplification unit comprises a first bootstrap follower amplification circuit and a second bootstrap follower amplification circuit;
the positive potential input end of the first bootstrap follow-up amplifying circuit is connected with the positive potential output end of the voltage output type sensor, the reference potential input end of the first bootstrap follow-up amplifying circuit is connected with a power ground, and the positive potential output end of the first bootstrap follow-up amplifying circuit is connected with the positive potential input end of the main amplifying unit;
the negative potential input end of the second bootstrap following amplifying circuit is connected with the negative potential output end of the voltage output type sensor, the reference potential input end of the second bootstrap following amplifying circuit is connected to the power ground, and the negative potential output end of the second bootstrap following amplifying circuit is connected with the negative potential input end of the main amplifying unit.
3. The floating differential amplification system of claim 2, wherein the first bootstrap follower amplification circuit comprises a resistor R1, a resistor R2, a resistor R3, a resistor R4, a capacitor C1, a capacitor C3, and an operational amplifier U1;
a first end of the capacitor C1 is a positive potential input end of the first bootstrap follower amplifying circuit, and a second end of the capacitor C1 is connected to a non-inverting input end of the operational amplifier U1 and a first end of the resistor R1;
the second end of the resistor R1 is connected with the first end of the resistor R2 and the first end of the resistor R3;
a second end of the resistor R2 is a reference potential input end of the first bootstrap follower amplifying circuit;
the second end of the resistor R3 is connected with the inverting input end of the operational amplifier U1, the first end of the resistor R4 and the first end of the capacitor C3 at the same time;
the common end of the output end of the operational amplifier U1, the second end of the resistor R4 and the second end of the capacitor C3 is a positive potential output end of the first bootstrap following amplifying circuit.
4. The floating differential amplification system of claim 3, wherein the second bootstrap follower amplification circuit comprises a resistor R5, a resistor R6, a resistor R7, a resistor R8, a capacitor C2, a capacitor C4 and an operational amplifier U2;
a first end of the capacitor C2 is a negative potential input end of the second bootstrap following amplifying circuit, and a second end of the capacitor C2 is connected to a non-inverting input end of the operational amplifier U2 and a first end of the resistor R5;
the second end of the resistor R5 is connected with the first end of the resistor R6 and the first end of the resistor R7;
a second end of the resistor R6 is a reference potential input end of the second bootstrap following amplifying circuit;
the second end of the resistor R7 is connected with the inverting input end of the operational amplifier U2, the first end of the resistor R8 and the first end of the capacitor C4 at the same time;
the common end of the output end of the operational amplifier U2, the second end of the resistor R8 and the second end of the capacitor C4 is a negative potential output end of the second bootstrap following amplifying circuit.
5. The floating differential amplification system of claim 4, wherein the pre-amplification cell further comprises a resistor R9;
the second end of the resistor R2 and the common end of the second end of the resistor R6 are connected to a protective ground through the resistor R9.
6. The floating differential amplification system of claim 2, wherein the main amplification unit comprises a first amplification circuit and a second amplification circuit;
a positive potential input end of the first amplifying circuit is a positive potential input end of the main amplifying unit, a reference potential input end of the first amplifying circuit is connected to the power ground, and a positive potential output end of the first amplifying circuit is connected with a positive potential input end of the differential analog-to-digital converter;
the negative potential input end of the second amplifying circuit is the negative potential input end of the main amplifying unit, the reference potential input end of the second amplifying circuit is connected to the power ground, and the negative potential output end of the second amplifying circuit is connected with the negative potential input end of the differential analog-to-digital converter.
7. The floating differential amplification system of claim 6, wherein the first amplification circuit comprises a resistor R10, a resistor R11, a capacitor C5, and an operational amplifier U3;
a first end of the resistor R10 is a positive potential input end of the first amplifying circuit, and a second end of the resistor R10 is connected to a first end of the resistor R11, a first end of the capacitor C5 and an inverting input end of the operational amplifier U3;
the non-inverting input end of the operational amplifier U3 is the reference potential input end of the first amplifying circuit;
the common end of the second end of the resistor R11, the second end of the capacitor C5 and the output end of the operational amplifier U3 is the positive potential output end of the first amplifying circuit.
8. The floating differential amplification system of claim 7, wherein the second amplification circuit comprises a resistor R12, a resistor R13, a capacitor C6, and an operational amplifier U4;
a first end of the resistor R12 is a negative potential input end of the second amplifying circuit, and a second end of the resistor R12 is connected to an inverting input end of the operational amplifier U4, a first end of the resistor R13 and a first end of the capacitor C6 at the same time;
the non-inverting input end of the operational amplifier U4 is the reference potential input end of the second amplifying circuit;
the output end of the operational amplifier U4, the common end of the second end of the resistor R13 and the second end of the capacitor C6 are the negative potential output end of the second amplifying circuit.
9. The floating differential amplification system of claim 6, wherein the differential analog-to-digital converter comprises an analog-to-digital converter chip U5, a capacitor C7, and a capacitor C8;
the common end of the first end of the capacitor C7 and the positive potential input pin of the analog-to-digital converter chip U5 is a positive potential input end of the differential analog-to-digital converter;
the first end of the capacitor C8 and the common end of the negative potential input pin of the analog-to-digital converter chip U5 are used as a negative potential input end of the differential analog-to-digital converter;
the second end of the capacitor C7 and the common end of the second end of the capacitor C8 are connected to the power ground.
10. The floating differential amplifier system of claim 1, wherein the voltage-output type sensor is an electromagnetic flow sensor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
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