High-precision and high-responsiveness ADC (Analog to Digital Converter) sampling system
By combining passive and active low-pass filters, the problems of limited filtering effect and slow response speed of passive low-pass filters are solved, realizing a high-precision, high-response ADC sampling system suitable for high-frequency signal processing.
Patent Information
- Application Number
- CN202520283899.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-21
- Publication Date
- 2026-01-02
- Estimated Expiration
- 2035-02-21
AI Technical Summary
Existing passive low-pass filters have limited filtering effect, are prone to signal attenuation, and have slow response speed, making them unable to effectively process signals input to ADC chips.
By combining passive and active low-pass filters, and using dual filtering methods, combined with operational amplifiers, the signal purity and system noise immunity are improved, thereby enhancing the accuracy and response speed of signal processing.
It improves signal purity and system noise immunity, enhances signal processing accuracy and response speed, and is suitable for high-precision, high-frequency signal processing.
Smart Images
Figure CN223758269U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to ADC sampling circuit technical field especially relates to a high accuracy high responsiveness ADC sampling system. BACKGROUND
[0002] The ADC sampling system is a kind of device that converts analog signal into digital signal, and plays a vital role in modern electronic system by sampling circuit to the continuous analog signal sampling, converts sampling data into digital signal, then after digital processing output.
[0003] In order to improve the precision of sampling, generally, passive low-pass filter is used to filter the signal sensed by pressure or temperature sensor in advance, and then sampled by ADC chip.Passive low-pass filter is used to remove high-frequency noise in signal, to ensure that the signal input to ADC chip is more pure and smooth.
[0004] Since passive low-pass filter is usually composed of resistance and capacitance, and specific frequency response is achieved through circuit design, it has the advantage of simple circuit, but has the problems of limited filtering effect, signal attenuation and slow response speed, so it cannot effectively process the signal input to ADC chip.
[0005] Therefore, a new technical solution is needed to solve the above technical problems. UTILITY MODEL CONTENT
[0006] The utility model aims at overcoming the problems of the prior art, and provides a high-precision and high-response ADC sampling system, which solves the problems of limited filtering effect, signal attenuation and slow response speed of the existing passive low-pass filter, and further cannot effectively process the signal input to the ADC chip.
[0007] The above object is achieved by the following technical solutions:
[0008] A high-precision and high-response ADC sampling system, comprising a passive low-pass filter circuit, an active low-pass filter circuit and an ADC chip connected in sequence, wherein the active low-pass filter circuit comprises an operational amplifier and a low-pass filter circuit connected to each other, the operational amplifier comprises a first pin, a second pin, a third pin, a fourth pin, a fifth pin, a sixth pin, a seventh pin and an eighth pin, the first pin and the fourth pin are connected to the passive low-pass filter circuit, the sixth pin and the seventh pin are connected to the low-pass filter circuit, and the low-pass filter circuit is connected to the ADC chip.
[0009] Further, the passive low-pass filter circuit comprises a twenty-ninth capacitor, a thirty-first capacitor, a thirty-third capacitor, an eighth resistor, a ninth resistor, a twelfth resistor and a fourteenth resistor, the twenty-ninth capacitor, the thirty-first capacitor and the thirty-third capacitor are connected in series and grounded, the twenty-ninth capacitor and the thirty-first capacitor are connected with one end of the ninth resistor respectively, the other end of the ninth resistor is connected with the connection, the other end of the eighth resistor is connected to a 5V power supply; the thirty-first capacitor and the thirty-third capacitor are connected with one end of the twelfth resistor respectively, the other end of the twelfth resistor is connected with the fourteenth resistor, and the other end of the fourteenth resistor is connected to a digital ground.
[0010] Further, the eleventh resistor is connected to the second pin and the third pin.
[0011] Further, the eighth pin is connected to a 5V power supply, and a thirtieth capacitor is arranged on the eighth pin for power decoupling and filtering.
[0012] Further, the operational amplifier is AD8227ARZ-R7.
[0013] Further, the low-pass filter circuit comprises a twenty-eighth capacitor, a thirty-second capacitor, a thirty-fourth capacitor, a tenth resistor and a thirteenth resistor, the twenty-eighth capacitor, the thirty-second capacitor and the thirty-fourth capacitor are connected in series and grounded, the twenty-eighth capacitor and the thirty-second capacitor are connected with one end of the tenth resistor respectively, and the other end of the tenth resistor is connected with the seventh pin; the thirty-second capacitor and the thirty-fourth capacitor are connected with one end of the thirteenth resistor respectively, and the other end of the thirteenth resistor is connected with the sixth pin.
[0014] Further, the ADC chip is ADS1262IPW.
[0015] The high-precision high-response ADC sampling system provided by the utility model adopts the combined application of passive low-pass filters and active low-pass filters, improves the signal purity and the anti-noise ability of the system through double filtering means, and has significant improvement in the precision, response speed and anti-interference ability of signal processing, and is suitable for application occasions requiring high-precision high-frequency signal processing. The advantages are as follows:
[0016] Double filtering: the combination of the basic passive filter and the active filter further improves the filtering effect and ensures the signal purity.
[0017] Signal amplification: the operational amplifier in the active filter amplifies the signal, improves the signal-to-noise ratio of the signal and the precision of ADC sampling.
[0018] Improve response speed: the fast response ability of the operational amplifier makes the system can handle the fast changing signal, improve dynamic performance.
[0019] Enhance anti-interference ability: the operational amplifier can enhance the signal while filtering, further suppress interference, and improve the anti-noise ability of the system. BRIEF DESCRIPTION OF DRAWINGS
[0020] Figure 1 The working principle block diagram of the high-precision high-response ADC sampling system is described in the utility model.
[0021] Figure 2 The circuit diagram of the high-precision high-response ADC sampling system is described in the utility model. DETAILED DESCRIPTION
[0022] The utility model will be further described in detail according to the drawings and examples. The described example is only a part of the utility model example, and is not all examples. Based on the example in the utility model, all other examples obtained by the ordinary skill in the art without making creative labor belong to the scope of the utility model protection.
[0023] As Figure 1 And Figure 2 The utility model provides a kind of high-precision high-response ADC sampling system, including sequentially connected passive low-pass filter circuit, active low-pass filter circuit and ADC chip U9.
[0024] The active low-pass filter circuit includes operational amplifier U8 and low-pass filter circuit connected with each other;The operational amplifier U8 includes first pin IN-, second pin RG ' , third pin RG '' , fourth pin IN+, fifth pin VS-, sixth pin REF, seventh pin VOUT and eighth pin VS+, and the first pin IN- and the fourth pin IN+ are connected with the passive low-pass filter circuit respectively, and the sixth pin REF and the seventh pin VOUT are connected with the low-pass filter circuit respectively, and the low-pass filter circuit is connected with the ADC chip.
[0025] As Figure 1 The working principle is as follows:
[0026] Sensor signal is subjected to basic filtering by the passive low-pass filter circuit, and then the weak sensor signal after basic filtering is amplified by the operational amplifier U8 of active low-pass filter circuit, and then subjected to secondary filtering by the low-pass filter circuit of active low-pass filter circuit, to finally realize inputting pure sensor signal to the ADC chip.
[0027] As a specific embodiment of the ADC chip U9 described in the present solution, its model is ADS1262IPW, which is a 32-bit ADC acquisition chip.
[0028] As shown in Figure 2 The passive low-pass filter circuit in the embodiment includes the twenty-ninth capacitor C29, the thirty-first capacitor C31, the thirty-third capacitor C33, the eighth resistor R8, the ninth resistor R9, the twelfth resistor R12, and the fourteenth resistor R14. The twenty-ninth capacitor C29, the thirty-first capacitor C31, and the thirty-third capacitor C33 are connected in series with each other and grounded. The twenty-ninth capacitor C29 and the thirty-first capacitor C31 are respectively connected with one end of the ninth resistor R9. The other end of the ninth resistor R9 is connected with the connection. The other end of the eighth resistor R8 is connected to a 5V power supply.
[0029] The thirty-first capacitor C31 and the thirty-third capacitor C33 are respectively connected with one end of the twelfth resistor R12. The other end of the twelfth resistor R12 is connected with the fourteenth resistor R14. The other end of the fourteenth resistor R14 is connected to a digital ground.
[0030] The passive low-pass filter circuit in the embodiment is used to filter high-frequency noise and smooth signals. The sensor signals are respectively input from the other end of the ninth resistor R9 SIG+ and the other end of the twelfth resistor R12 SIG-. The twenty-ninth capacitor C29, the thirty-first capacitor C31, and the thirty-third capacitor C33 are used for high-frequency filtering. The eighth resistor R8, the ninth resistor R9, the twelfth resistor R12, and the fourteenth resistor R14 are used for signal conditioning and matching.
[0031] The sensor signals filtered by the passive low-pass filter circuit are input to the first pin IN- and the fourth pin IN+ of the operational amplifier U8 for signal amplification processing.
[0032] The second pin RG ' and the third pin RG '' are connected with the eleventh resistor R11.
[0033] The eleventh resistor R11 in the embodiment mainly functions to set the gain of the amplifier. That is, by changing the value of the eleventh resistor R11, the gain of the operational amplifier U8 can be adjusted. The higher the gain, the greater the amplification multiple of the input signal.
[0034] The eighth pin VS+ is connected to a 5V power supply, and the thirtieth capacitor C30 is arranged on the eighth pin VS+ for power decoupling and filtering.
[0035] Specifically, the thirtieth capacitor C30 in the embodiment is a composite capacitor composed of two capacitors 0.1 µF and 100 nF in series, which helps to ensure the stability of the power supply by providing decoupling and filtering functions, and the stable power supply voltage is crucial to maintaining the performance of the operational amplifier U8, thereby improving the reliability and performance of the entire circuit.
[0036] As a specific embodiment of the present scheme, the model of the operational amplifier U8 is AD8227ARZ-R7.
[0037] Specifically, AD8227ARZ-R7 is a low-cost, wide-input-range instrumentation amplifier that provides up to 80 dB of common-mode rejection (CMR) and very high input impedance (800 MΩ differential and 400 MΩ common). In combination with the passive low-pass filter amplifier, the differential input of the AD8227 is filtered by two 4.02 kΩ resistors (R9 and R12) and a 10 nF capacitor (C31), which form a single-pole RC filter with a cutoff frequency of 2.0 kHz. Two 1 nF capacitors (C29 and C33) add common-mode filtering with a cutoff frequency of 40 kHz.
[0038] As shown in Figure 2 As an optimization of the low-pass filter circuit in the present active low-pass filter circuit, the low-pass filter circuit includes a twenty-eighth capacitor C28, a thirty-second capacitor C32, a thirty-fourth capacitor C34, a tenth resistor R10, and a thirteenth resistor R13, the twenty-eighth capacitor C28, the thirty-second capacitor C32, and the thirty-fourth capacitor C34 are connected to each other and grounded, one end of the tenth resistor R10 is connected to the twenty-eighth capacitor C28 and the thirty-second capacitor C32 respectively, the other end of the tenth resistor R10 is connected to the seventh pin VOUT;
[0039] The other end of the thirteenth resistor R13 is connected to the sixth pin REF.
[0040] The low-pass filter circuit in the embodiment is used to filter high-frequency noise in the signal input through the seventh pin VOUT of the operational amplifier U8, while providing DC bias, ensuring the stability and accuracy of the input signal, and inputting the processed sensor signal to the ADC chip for collection.
[0041] The above merely describes the implementation of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made by those skilled in the art within the spirit and principles of the present application shall be included in the protection scope of the present application.
Claims
1. A high-precision, high-response ADC sampling system, characterized in that, It includes a passive low-pass filter circuit, an active low-pass filter circuit, and an ADC chip (U9) connected in sequence. The active low-pass filter circuit includes an operational amplifier (U8) and a low-pass filter circuit connected to each other; the operational amplifier (U8) includes a first pin (IN-) and a second pin (RG). ' ), third pin (RG) '' The circuit consists of four pins: IN+, VS-, REF, VOUT, and VS+. The first pin (IN-) and the fourth pin (IN+) are connected to the passive low-pass filter circuit, and the sixth pin (REF) and the seventh pin (VOUT) are connected to the low-pass filter circuit. The low-pass filter circuit is connected to the ADC chip.
2. The high-precision, high-response ADC sampling system according to claim 1, characterized in that, The passive low-pass filter circuit includes a 29th capacitor (C29), a 31st capacitor (C31), a 33rd capacitor (C33), an 8th resistor (R8), a 9th resistor (R9), a 12th resistor (R12), and a 14th resistor (R14). The 29th capacitor (C29), the 31st capacitor (C31), and the 33rd capacitor (C33) are connected in series and grounded. The 29th capacitor (C29) and the 31st capacitor (C31) are each connected to one end of the 9th resistor (R9). The other end of the 9th resistor (R9) is connected to the ground. The other end of the 8th resistor (R8) is connected to a 5V power supply. The thirty-first capacitor (C31) and the thirty-third capacitor (C33) are respectively connected to one end of the twelfth resistor (R12), the other end of the twelfth resistor (R12) is connected to the fourteenth resistor (R14), and the other end of the fourteenth resistor (R14) is connected to digital ground.
3. A high-precision, high-response ADC sampling system according to claim 1 or 2, characterized in that, The second pin (RG) ' ) and the third pin (RG) '' The eleventh resistor (R11) is connected to it.
4. The high-precision, high-response ADC sampling system according to claim 3, characterized in that, The eighth pin (VS+) is connected to a 5V power supply, and a thirtieth capacitor (C30) is provided on the eighth pin (VS+) for power supply decoupling and filtering.
5. The high-precision, high-response ADC sampling system according to claim 1, characterized in that, The operational amplifier (U8) is model AD8227ARZ-R7.
6. The high-precision, high-response ADC sampling system according to claim 1, characterized in that, The low-pass filter circuit includes a 28th capacitor (C28), a 32nd capacitor (C32), a 34th capacitor (C34), a 10th resistor (R10), and a 13th resistor (R13). The 28th capacitor (C28), the 32nd capacitor (C32), and the 34th capacitor (C34) are interconnected and grounded. The 28th capacitor (C28) and the 32nd capacitor (C32) are each connected to one end of the 10th resistor (R10), and the other end of the 10th resistor (R10) is connected to the 7th pin (VOUT). The thirty-second capacitor (C32) and the thirty-fourth capacitor (C34) are respectively connected to one end of the thirteenth resistor (R13), and the other end of the thirteenth resistor (R13) is connected to the sixth pin (REF).
7. The high-precision, high-response ADC sampling system according to claim 1, characterized in that, The ADC chip (U9) is model ADS1262IPW.