ADC sampling signal filtering and amplifying circuit

Abstract

The utility model discloses an ADC sampling signal filtering and amplifying circuit which comprises an operational amplifying circuit, a power amplifying circuit and an anti-aliasing filtering circuit which are connected in sequence. The operational amplifier circuit adopts a rail-to-rail output two-way operational amplifier and comprises an amplifier A1, and a first-stage operational amplifier module and a second-stage operational amplifier module which are connected with the amplifier A1; the anti-aliasing filter circuit comprises a filter module, a first discharge module and a second discharge module. The first discharge module and the second discharge module are connected through the filtering module. The operational amplification circuit is arranged to convert differential current input into single-end voltage output, the complexity of electric signals is reduced, the power amplification circuit is arranged to preliminarily amplify voltage signals, the anti-aliasing filter circuit is arranged to further filter noise to obtain signals with normal sampling frequency, and the sampling frequency is improved by filtering frequency components higher than the sampling frequency. And the aliasing phenomenon is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic circuits, in particular to an ADC sampling signal filtering and amplifying circuit. Background Art

[0002] During the information acquisition process, the DAC module converts the discrete digital sinusoidal signal generated by the FPGA into an analog sinusoidal signal. The amplification circuit amplifies the analog sinusoidal signal and outputs it to the operational amplifier. The operational amplifier directly affects the performance of the entire circuit system. In high-frequency systems, the operational amplifier is likely to experience excessive gain attenuation, causing the system to malfunction. When the frequency contained in the analog signal is higher than the frequency range required by the sampling theorem, this high-frequency information will be incorrectly represented as low-frequency information, causing high-frequency and low-frequency signals to alias and lead to sampling frequency disorder. Utility Model Content

[0003] The technical problem to be solved by the present invention is that when the gain attenuation of the operational amplifier in the circuit is too large, aliasing is easily generated during analog-to-digital conversion of the sampled signal, resulting in sampling frequency disorder. The purpose is to provide an ADC sampling signal filtering and amplification circuit. By configuring an operational amplifier circuit to convert the differential current input into a single-ended voltage output, the complexity of the electrical signal is reduced. A power amplifier circuit is configured to initially amplify the voltage signal. At the same time, to meet the needs of the subsequent anti-aliasing filter circuit, the anti-aliasing filter circuit further filters out noise to obtain a signal with a normal sampling frequency. By filtering out frequency components higher than the sampling frequency, aliasing is avoided. This ensures that only frequency components below the sampling frequency are sampled and correctly represented in the digital signal.

[0004] The utility model is achieved through the following technical solutions:

[0005] An ADC sampling signal filtering and amplifying circuit comprises an operational amplifier circuit, a power amplifier circuit and an anti-aliasing filtering circuit connected in sequence;

[0006] The operational amplifier circuit adopts a dual-channel operational amplifier with rail-to-rail output, and the operational amplifier circuit includes an amplifier A1, and a first-stage operational amplifier module and a second-stage operational amplifier module connected to the amplifier A1;

[0007] The anti-aliasing filter circuit includes a filter module, a first discharge module and a second discharge module;

[0008] The first discharge module and the second discharge module are connected through a filter module.

[0009] The utility model reduces the complexity of the electrical signal by providing an operational amplifier circuit to convert the differential current input into a single-ended voltage output. A power amplifier circuit is provided to initially amplify the voltage signal. At the same time, to meet the needs of the subsequent anti-aliasing filter circuit, the anti-aliasing filter circuit further filters out noise to obtain a signal with a normal sampling frequency. By filtering out frequency components above the sampling frequency, the occurrence of aliasing is avoided. This ensures that only frequency components below the sampling frequency are sampled and correctly represented in the digital signal.

[0010] Furthermore, the first-stage operational amplifier module includes a resistor R1, a resistor R2, a capacitor C1, and a capacitor C2;

[0011] The resistor R1 and the capacitor C2 are connected in sequence;

[0012] The non-inverting input terminal of the amplifier A1 is connected to the resistor R2 and the capacitor C1;

[0013] The other end of the resistor R2 connected to the capacitor C1 is connected to the resistor R1 and the capacitor C2, and the other end of the capacitor C2 is connected to the output end of the amplifier A1.

[0014] Furthermore, the resistor R2 and the capacitor C1 form a filter circuit.

[0015] Furthermore, the second-stage operational amplifier module includes a resistor R3 and a resistor R4;

[0016] One end of the resistor R3 and the resistor R4 are both connected to the inverting input end of the amplifier A1;

[0017] The other end of the resistor R3 is connected to the output end of the amplifier;

[0018] The other end of the resistor R4 is grounded.

[0019] Furthermore, the power amplifier circuit includes a resistor R5, a resistor R6, a capacitor C3, a capacitor C4, a capacitor C5 and a capacitor C6;

[0020] The two ends of the resistor R5 are connected to the inverting input terminal and the output terminal of the amplifier A2 respectively;

[0021] One end of the resistor R6 is connected to the inverting input terminal of the amplifier A2, and the other end is grounded;

[0022] The capacitor C3 and the capacitor C4 are connected in parallel and connected to the positive power supply interface of the amplifier A2;

[0023] The capacitor C5 and the capacitor C6 are connected in parallel and connected to the negative power supply interface of the amplifier A2.

[0024] Furthermore, the non-inverting input terminal of the amplifier A2 is connected to the output terminal of the amplifier A1.

[0025] Furthermore, the first discharge module includes an amplifier A3, and a resistor R8 and a resistor R10 connected to the output end of the amplifier A3 in sequence.

[0026] Furthermore, the second discharge module includes an amplifier A4, and a resistor R11 and a resistor R12 connected to the output terminal of the amplifier A4 in sequence.

[0027] Furthermore, the filtering module includes a resistor R7, a resistor R9 and a capacitor C7 connected in sequence, and a capacitor C8 connected between the resistor R7 and the resistor R9.

[0028] Furthermore, the resistor R7 is connected to the output end of the amplifier A3, the resistor R9 is connected to the non-inverting input end of the amplifier A4, one end of the capacitor C7 connected to the resistor R9 is also connected to the non-inverting input end of the amplifier A4, and the other end of the capacitor C8 connected to the resistor R9 is connected to the inverting input end of the amplifier A4.

[0029] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0030] By setting up an operational amplifier circuit to convert the differential current input into a single-ended voltage output, the complexity of the electrical signal is reduced. A power amplifier circuit is set up to initially amplify the voltage signal to meet the needs of the subsequent anti-aliasing filter circuit. The anti-aliasing filter circuit further filters out noise to obtain a signal with a normal sampling frequency. By filtering out frequency components above the sampling frequency, aliasing is avoided. This ensures that only frequency components below the sampling frequency are sampled and correctly represented in the digital signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the accompanying drawings:

[0032] Figure 1 This is an overall structural diagram of the ADC sampling signal filtering and amplifying circuit in an embodiment of the present utility model. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The schematic implementation methods of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0034] As a possible implementation, Figure 1As shown, this embodiment provides an ADC sampling signal filtering and amplification circuit, comprising an operational amplifier circuit, a power amplifier circuit, and an anti-aliasing filter circuit connected in sequence. The operational amplifier circuit uses a dual-channel operational amplifier with rail-to-rail output, and the operational amplifier circuit includes amplifier A1, as well as a first-stage operational amplifier module and a second-stage operational amplifier module connected to amplifier A1. The anti-aliasing filter circuit includes a filter module, a first discharge module, and a second discharge module; the first discharge module and the second discharge module are connected through the filter module. This embodiment reduces the complexity of the electrical signal by providing an operational amplifier circuit pair to convert the differential current input into a single-ended voltage output. The power amplifier circuit is provided to initially amplify the voltage signal to meet the needs of the subsequent anti-aliasing filter circuit. The anti-aliasing filter circuit further filters out noise to obtain a signal with a normal sampling frequency. By filtering out frequency components above the sampling frequency, aliasing is avoided. This ensures that only frequency components below the sampling frequency are sampled and correctly represented in the digital signal.

[0035] In some possible embodiments, the first-stage operational amplifier module includes a resistor R1, a resistor R2, a capacitor C1, and a capacitor C2; the resistor R1 and the capacitor C2 are connected in sequence; the non-inverting input end of the amplifier A1 is connected to the resistor R2 and the capacitor C1, and the other end of the capacitor C1 is grounded; the other end of the resistor R2 connected to the capacitor C1 is connected to the resistor R1 and the capacitor C2, and the other end of the capacitor C2 is connected to the output end of the amplifier A1.

[0036] In some possible embodiments, the resistor R2 and the capacitor C1 form a filtering circuit. The second-order low-pass filter constructed by the resistor R2 and the capacitor C1 reduces the high-frequency components in the signal to a negligible level, thereby reducing system errors.

[0037] In some possible embodiments, the second-stage operational amplifier module includes resistors R3 and R4; one end of each resistor R3 and R4 is connected to the inverting input of amplifier A1; the other end of resistor R3 is connected to the output of the amplifier; and the other end of resistor R4 is grounded.

[0038] In some possible embodiments, complex load impedances in general power operational amplifier applications may result in output stage instability. The power amplifier circuit provides stable compatibility. The power amplifier circuit includes resistor R5, resistor R6, capacitor C3, capacitor C4, capacitor C5, and capacitor C6; resistor R5 is connected to the inverting input and output of amplifier A2, respectively; resistor R6 is connected to the inverting input of amplifier A2 at one end and grounded at the other end; capacitors C3 and C4 are connected in parallel to the positive power supply interface of amplifier A2; and capacitors C5 and C6 are connected in parallel to the negative power supply interface of amplifier A2. The parallel circuit of capacitors C3 and C4 is grounded at the end away from amplifier A2, and the parallel circuit of capacitors C5 and C6 is also grounded at the end away from amplifier A2.

[0039] In some possible embodiments, the non-inverting input terminal of the amplifier A2 is connected to the output terminal of the amplifier A1.

[0040] In some possible embodiments, the voltage signal after passing through the amplifier A2 is initially amplified. At this time, the voltage signal is still mixed with various noises. It needs to be further filtered out by anti-aliasing filtering before it can be transmitted to the A / D. The anti-aliasing filtering specifically includes: a first discharge module, a second discharge module, and a filter module:

[0041] The first discharge module includes an amplifier A3, and resistors R8 and R10 connected to the output terminal of the amplifier A3 in sequence. The end of the resistor R10 away from the resistor R8 is grounded.

[0042] The second discharge module includes an amplifier A4, and a resistor R11 and a resistor R12 connected to the output terminal of the amplifier A4 in sequence. The end of the resistor R12 away from the resistor R11 is grounded.

[0043] The filter module includes resistor R7, resistor R9, and capacitor C7 connected in sequence, as well as capacitor C8 connected between resistors R7 and R9. Resistor R7 is connected to the output of amplifier A3, resistor R9 is connected to the non-inverting input of amplifier A4, one end of capacitor C7 connected to resistor R9 is also connected to the non-inverting input of amplifier A4, the other end of capacitor C7 is grounded, and the other end of capacitor C8 connected to resistor R9 is connected to the inverting input of amplifier A4.

[0044] The specific implementation methods described above further illustrate the purpose, technical solutions and beneficial effects of the utility model in detail. It should be understood that the above description is only a specific implementation method of the utility model and is not intended to limit the scope of protection of the utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the utility model should be included in the scope of protection of the utility model.

Claims

1. An ADC sampling signal filtering and amplifying circuit, characterized in that: include: An operational amplifier circuit, a power amplifier circuit and an anti-aliasing filter circuit connected in sequence; The operational amplifier circuit adopts a dual-channel operational amplifier with rail-to-rail output, and the operational amplifier circuit includes an amplifier A1, and a first-stage operational amplifier module and a second-stage operational amplifier module connected to the amplifier A1; The anti-aliasing filter circuit includes a filter module, a first discharge module and a second discharge module; The first discharge module and the second discharge module are connected through a filter module.

2. The ADC sampling signal filtering and amplifying circuit according to claim 1, wherein: The first-stage operational amplifier module includes a resistor R1, a resistor R2, a capacitor C1 and a capacitor C2; The resistor R1 and the capacitor C2 are connected in sequence; The non-inverting input terminal of the amplifier A1 is connected to the resistor R2 and the capacitor C1; The other end of the resistor R2 connected to the capacitor C1 is connected to the resistor R1 and the capacitor C2, and the other end of the capacitor C2 is connected to the output end of the amplifier A1.

3. The ADC sampling signal filtering and amplifying circuit according to claim 2, wherein: The resistor R2 and the capacitor C1 form a filter circuit.

4. The ADC sampling signal filtering and amplifying circuit according to claim 2, wherein: The second-stage operational amplifier module includes a resistor R3 and a resistor R4; One end of the resistor R3 and the resistor R4 are both connected to the inverting input end of the amplifier A1; The other end of the resistor R3 is connected to the output end of the amplifier; The other end of the resistor R4 is grounded.

5. The ADC sampling signal filtering and amplifying circuit according to claim 4, characterized in that: The power amplifier circuit includes a resistor R5, a resistor R6, a capacitor C3, a capacitor C4, a capacitor C5 and a capacitor C6; The two ends of the resistor R5 are connected to the inverting input terminal and the output terminal of the amplifier A2 respectively; One end of the resistor R6 is connected to the inverting input terminal of the amplifier A2, and the other end is grounded; The capacitor C3 and the capacitor C4 are connected in parallel and connected to the positive power supply interface of the amplifier A2; The capacitor C5 and the capacitor C6 are connected in parallel and connected to the negative power supply interface of the amplifier A2.

6. The ADC sampling signal filtering and amplifying circuit according to claim 5, characterized in that: The non-inverting input terminal of the amplifier A2 is connected to the output terminal of the amplifier A1.

7. The ADC sampling signal filtering and amplifying circuit according to claim 1, wherein: The first discharge module includes an amplifier A3, and a resistor R8 and a resistor R10 connected to the output end of the amplifier A3 in sequence.

8. The ADC sampling signal filtering and amplifying circuit according to claim 7, wherein: The second discharge module includes an amplifier A4, and a resistor R11 and a resistor R12 connected to the output terminal of the amplifier A4 in sequence.

9. The ADC sampling signal filtering and amplifying circuit according to claim 8, characterized in that: The filtering module includes a resistor R7, a resistor R9 and a capacitor C7 connected in sequence, and a capacitor C8 connected between the resistor R7 and the resistor R9.

10. The ADC sampling signal filtering and amplifying circuit according to claim 9, characterized in that: The resistor R7 is connected to the output end of the amplifier A3, the resistor R9 is connected to the non-inverting input end of the amplifier A4, one end of the capacitor C7 is connected to the resistor R9 and is also connected to the non-inverting input end of the amplifier A4, and the other end of the capacitor C8 is connected to the resistor R9 and is connected to the inverting input end of the amplifier A4.

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