Continuous voltage signal segmented sampling circuit

Abstract

The invention discloses a continuous voltage signal segmented sampling circuit comprising an analog switch module used for switching different sampling segments; the reference voltage source is electrically connected with the analog switch module, and a resistance feedback network of the reference voltage source is adjusted through switching of an analog switch path, so that different reference voltage values are generated; the reference voltage module is electrically connected with the reference voltage source, and the reference voltage module is used for generating segmented reference voltage; the subtraction module is used for receiving the continuous voltage signal to be sampled, is electrically connected with the reference voltage module and is used for generating a voltage difference value between the continuous voltage signal to be sampled and the segmented reference voltage under different segments; and the proportional amplification module is used for amplifying the voltage difference value and then outputting the amplified voltage difference value and is electrically connected with the subtraction operation module. According to the invention, the problem that sampling of continuous voltage signals in a high-noise environment is easily interfered in the prior art is solved.

Description

Technical Field

[0001] The invention relates to the technical field of electronic circuits, and in particular to a continuous voltage signal segmented sampling circuit. Background Art

[0002] In the closed-loop control of switching power supplies, it is necessary to accurately sample the output current. The traditional application circuit uses a current sensor to convert the current signal into a continuous voltage signal and output it to the AD port of the processor for sampling. In this application, a typical problem is that the sampled voltage value output by the current sensor to the AD port of the processor after conversion is relatively small. For example, a current sensor with a range of 100A has a sampled output voltage range of 0-3V to the AD port of the processor, that is, the change in output current of 1A corresponds to a voltage change of only 30mV on the AD port. In the high-noise internal environment of the switching power supply, it is easy to be submerged by noise, resulting in distortion of the sampled value. Summary of the invention

[0003] The present invention provides a continuous voltage signal segmented sampling circuit, which solves the problem in the prior art that the continuous voltage signal is easily disturbed when being sampled in a high noise environment.

[0004] The technical solutions to the above problems are as follows: A continuous voltage signal segmented sampling circuit, comprising: Analog switch module, the analog switch module is used to switch different sampling segments; A reference voltage source, the reference voltage source is electrically connected to the analog switch module, and a resistance feedback network of the reference voltage source is adjusted by switching the analog switch path to generate different reference voltage values; A reference voltage module, the reference voltage module is electrically connected to a reference voltage source, and the reference voltage module is used to generate a segmented reference voltage; A subtraction operation module receiving the continuous voltage signal to be sampled, the subtraction operation module being electrically connected to the reference voltage module, and used to generate a voltage difference between the continuous voltage signal to be sampled and the segment reference voltage under different segments; The proportional amplification module amplifies the voltage difference and outputs the result, and the proportional amplification module is electrically connected to the subtraction operation module.

[0005] The working process of the present invention is: the path from the first output control pin to the third output control pin of the analog switch chip is controlled by the three IO ports of the processor to change the voltage value at both ends of the sixth resistor, thereby adjusting the output voltage value of the precision parallel regulator to obtain different segmented reference voltages. The voltage to be sampled is input to the same direction input terminal of the first operational amplifier through the tenth resistor, and the segmented reference voltage is input to the reverse input terminal of the first operational amplifier through the eighth resistor. The output voltage value of the first operational amplifier is equal to the continuous voltage value to be sampled minus the segmented reference voltage value, and is input to the reverse input terminal of the second operational amplifier through the ninth resistor. The second operational amplifier amplifies the voltage difference and inputs it to the sampling port of the processor after current limiting through the eleventh resistor.

[0006] The advantages of the present invention are as follows: the present invention solves the problem in the prior art that continuous voltage signals are susceptible to interference when being sampled in a high noise environment, and improves the accuracy of reflecting the actual changes of the continuous voltage signal to be sampled through the amplified voltage.

[0007] The present invention can be transplanted into projects that require large-current and large-range sampling, shortening the product development cycle and improving project reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a circuit block diagram of the continuous voltage signal segmented sampling circuit of the present invention.

[0009] Figure 2 This is the circuit schematic diagram of the analog switch module.

[0010] Figure 3 This is the circuit schematic diagram of the reference voltage source and reference voltage module.

[0011] Figure 4 This is the circuit schematic diagram of the subtraction module and the proportional amplification module. DETAILED DESCRIPTION

[0012] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0013] like Figures 1 to 4 A continuous voltage signal segmented sampling circuit of the present invention includes: an analog switch module 1, a reference voltage source 2, a reference voltage module 3, a subtraction operation module 4, and a proportional amplification module 5. Each part and the relationship between them are described in detail below.

[0014] The analog switch module 1 is used to switch different sampling segments. The analog switch module 1 includes an analog switch chip U1, a first capacitor C1, and a second capacitor C2. One end of the first capacitor C1 and the second capacitor C2 are both connected to the power input end of the analog switch chip U1, and one end of the first capacitor C1 and the second capacitor C2, and the other end of the first capacitor C1 and the second capacitor C2 are grounded.

[0015] The analog switch chip U1 has a first input control pin S0, a second input control pin S1, and a third input control pin S2. The analog switch chip U1 has a first output control pin Y0, a second output control pin Y1, a third output control pin Y2, and a third output control pin Y3, wherein the first input control pin S0, the second input control pin S1, and the third input control pin S2 are respectively connected to three IO ports (MCU_IO1-MCU_IO3) of a processor (not shown in the figure), and the four pin paths from the first output control pin Y0 to the third output control pin Y3 are controlled by the three IO ports of the processor to be connected to pin Z of the analog switch chip U1.

[0016] The reference voltage source 2 is electrically connected to the analog switch module 1, and the resistance feedback network of the reference voltage source 2 is adjusted by switching the analog switch 1 path to generate different reference voltage values. The reference voltage module 3 is electrically connected to the reference voltage source 2, and the reference voltage module 1 is used to generate segmented reference voltages.

[0017] The reference voltage module 3 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a third capacitor C3, a fourth capacitor C4, and a fifth capacitor C5. One end of the first resistor R1, the third capacitor C3, and the fourth capacitor C4 is used to connect to a working voltage, which is a 5V DC voltage, and the other end of the fourth capacitor C4 and the fifth capacitor C5 is grounded. In this embodiment, the first resistor R1 is a current limiting resistor, and the third capacitor C3, the fourth capacitor C4, and the fifth capacitor C5 are all filter capacitors.

[0018] One end of the second resistor R2, the third resistor R3, the fourth resistor R4, the fifth resistor R5, and the fifth capacitor C5 are respectively connected to the other end of the first resistor R1, and the other ends of the second resistor R2, the third resistor R3, the fourth resistor R4, and the fifth resistor R5 are respectively connected to the analog switch module 1. Specifically: the other end of the second resistor R2 is connected to the first output control pin Y0, the other end of the third resistor R3 is connected to the second output control pin Y1, the other end of the fourth resistor R4 is connected to the third output control pin Y2, and the other end of the fifth resistor R5 is connected to the fourth output control pin Y3.

[0019] One end of the sixth resistor R6, the other end of the fifth capacitor C5, and the first end of the reference voltage source 2 are grounded, the other end of the sixth resistor R6 and the second end of the reference voltage source 2 are both connected to the analog switch module 1, and the third end of the reference voltage source 2 is connected to the other end of the first resistor R1. In this embodiment, the reference voltage source 2 preferably adopts an adjustable precision parallel regulator U2. The other end of the sixth resistor R6 and the second end of the adjustable precision parallel regulator U2 are both connected to pin Z of the analog switch chip U1. By controlling the connection between the first output control pin Y0 to the third output control pin Y3 and pin Z respectively, the voltage value across the sixth resistor R6 is changed, thereby adjusting the output voltage value of the adjustable precision parallel regulator U2 to obtain different segmented reference voltages.

[0020] The subtraction operation module 4 receives the continuous voltage signal to be sampled, and is electrically connected to the reference voltage module 3, and is used to generate voltage differences between the continuous voltage signal to be sampled and the segment reference voltage under different segments.

[0021] The subtraction operation module 4 includes a first operational amplifier U3, a seventh resistor R7, an eighth resistor R8, a tenth resistor R10, and a twelfth resistor R12. One end of the eighth resistor R8 is connected to the output end of the reference voltage module 3, and the other end of the eighth resistor R8 is connected to the inverting input end of the first operational amplifier U3. One end of the tenth resistor R10 is used to receive the continuous voltage signal to be sampled, and the other end of the tenth resistor R10 and one end of the twelfth resistor R12 are both connected to the in-phase input end of the first operational amplifier U3, and the other end of the twelfth resistor R12 is grounded. One end of the seventh resistor R7 is connected to the inverting input end of the first operational amplifier U3, and the other end of the seventh resistor R7 is connected to the output end of the first operational amplifier U3. In this embodiment, the seventh resistor R7, the eighth resistor R8, the tenth resistor R10, and the twelfth resistor R12 have the same resistance value.

[0022] The subtraction operation module 4 also includes a seventh capacitor C7 and a ninth resistor R9. The seventh capacitor C7 is a filter capacitor, and the ninth resistor R9 is an output current limiting resistor. One end of the seventh capacitor C7 is connected to the power input end of the first operational amplifier U3, and the other end of the seventh capacitor C7 is grounded. One end of the ninth resistor R9 is connected to the output end of the first operational amplifier U3, and the other end of the ninth resistor R9 is connected to the proportional amplification module 5.

[0023] The proportional amplification module 5 amplifies the voltage difference and outputs it, and the proportional amplification module 5 is electrically connected to the subtraction operation module 4. The proportional amplification module 5 includes a second operational amplifier U4, an eleventh resistor R11, a thirteenth resistor R13, and a fourteenth resistor R14. In this embodiment, the eleventh resistor R11 is a current limiting resistor, and the thirteenth resistor R13 and the fourteenth resistor R14 have the same resistance value.

[0024] The inverting input terminal of the second operational amplifier U4 is connected to the output terminal of the subtraction operation module 4. In this embodiment, the inverting input terminal of the second operational amplifier U4 is connected to the other end of the ninth resistor R9 in the subtraction operation module 4, and the non-inverting input terminal of the second operational amplifier U4 is respectively connected to one end of the thirteenth resistor R13 and the fourteenth resistor R14, the other end of the fourteenth resistor R14 is grounded, and the other end of the thirteenth resistor R13 and one end of the eleventh resistor R11 are both connected to the output terminal of the second operational amplifier U4.

[0025] The proportional amplification module 5 also includes a voltage stabilizing filter circuit, which includes a sixth capacitor C6 and a voltage stabilizing diode ZD1. One end of the sixth capacitor C6 and the cathode end of the voltage stabilizing diode ZD1 are connected to the other end of the eleventh resistor R11, and one end of the sixth capacitor C6 and the anode end of the voltage stabilizing diode ZD1 are grounded.

[0026] The proportional amplification module 5 also includes an eighth capacitor C8, one end of which is connected to the power input terminal of the second operational amplifier U4, and the other end of the eighth capacitor C8 is grounded. The eighth capacitor C8 filters the 5V working voltage provided to the second operational amplifier U4.

[0027] The working process of the present invention is: the path from the first output control pin Y0 to the third output control pin Y3 of the analog switch chip U1 is controlled through the three IO ports of the processor to change the voltage value at both ends of the sixth resistor R6, thereby adjusting the output voltage value of the precision parallel regulator U2 to obtain different segmented reference voltages. The voltage to be sampled is input to the same-direction input terminal of the first operational amplifier U3 through the tenth resistor R10, and the segmented reference voltage is input to the reverse input terminal of the first operational amplifier U3 through the eighth resistor R8. The output voltage value of the first operational amplifier U3 is equal to the continuous voltage value to be sampled minus the segmented reference voltage value, and is input to the reverse input terminal of the second operational amplifier U4 through the ninth resistor R9. The second operational amplifier U4 amplifies the voltage difference and inputs it to the AD sampling port of the processor after current limiting through the eleventh resistor R11.

[0028] Finally, it should be noted that the above-described implementation mode is only a preferred embodiment of the present invention to illustrate the technical solution of the present invention, and does not limit it, let alone limit the protection scope of the present invention; although the invention is described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the protection scope of the claims.

Claims

1. A continuous voltage signal segmented sampling circuit, characterized in that: include: An analog switch module (1), the analog switch module (1) is used to switch different sampling segments; A reference voltage source (2), the reference voltage source (2) being electrically connected to the analog switch module (1), and adjusting the resistance feedback network of the reference voltage source (2) by switching the path of the analog switch (1) to generate different reference voltage values; A reference voltage module (3), the reference voltage module (3) is electrically connected to the reference voltage source (2), and the reference voltage module (1) is used to generate a segmented reference voltage; A subtraction operation module (4) receives the continuous voltage signal to be sampled, the subtraction operation module (4) is electrically connected to the reference voltage module (3) and is used to generate voltage differences between the continuous voltage signal to be sampled and the segment reference voltage under different segments; A proportional amplification module (5) is provided for amplifying the voltage difference and outputting the amplified voltage difference. The proportional amplification module (5) is electrically connected to the subtraction operation module (4).

2. A continuous voltage signal segmented sampling circuit according to claim 1, characterized in that: The analog switch module (1) comprises an analog switch chip (U1), a first capacitor (C1), and a second capacitor (C2), wherein one end of the first capacitor (C1) and the second capacitor (C2) are both connected to a power input end of the analog switch chip (U1), and one end of the first capacitor (C1) and the second capacitor (C2) and the other end of the first capacitor (C1) and the second capacitor (C2) are grounded.

3. A continuous voltage signal segmented sampling circuit according to claim 1, characterized in that: The reference voltage module (3) comprises a first resistor (R1), a second resistor (R2), a third resistor (R3), a fourth resistor (R4), a fifth resistor (R5), a sixth resistor (R6), a third capacitor (C3), a fourth capacitor (C4), and a fifth capacitor (C5); One end of the first resistor (R1), the third capacitor (C3) and the fourth capacitor (C4) is used to connect to the working voltage, and the other end of the fourth capacitor (C4) and the fifth capacitor (C5) is grounded; One end of the second resistor (R2), the third resistor (R3), the fourth resistor (R4), the fifth resistor (R5), and the fifth capacitor (C5) are respectively connected to the other end of the first resistor (R1), and the other ends of the second resistor (R2), the third resistor (R3), the fourth resistor (R4), and the fifth resistor (R5) are respectively connected to the analog switch module (1); One end of the sixth resistor (R6), the other end of the fifth capacitor (C5), and the first end of the reference voltage source (2) are grounded, the other end of the sixth resistor (R6) and the second end of the reference voltage source (2) are both connected to the analog switch module (1), and the third end of the reference voltage source (2) is connected to the other end of the first resistor (R1).

4. The continuous voltage signal segmented sampling circuit according to claim 1, characterized in that: The subtraction operation module (4) comprises a first operational amplifier (U3), a seventh resistor (R7), an eighth resistor (R8), a tenth resistor (R10), and a twelfth resistor (R12); One end of the eighth resistor (R8) is connected to the output end of the reference voltage module (3), and the other end of the eighth resistor (R8) is connected to the inverting input end of the first operational amplifier (U3); One end of the tenth resistor (R10) is used to receive the continuous voltage signal to be sampled, the other end of the tenth resistor (R10) and one end of the twelfth resistor (R12) are both connected to the in-phase input end of the first operational amplifier (U3), and the other end of the twelfth resistor (R12) is grounded; One end of the seventh resistor (R7) is connected to the inverting input end of the first operational amplifier (U3), and the other end of the seventh resistor (R7) is connected to the output end of the first operational amplifier (U3).

5. A continuous voltage signal segmented sampling circuit according to claim 4, characterized in that: The subtraction operation module (4) further comprises a ninth resistor (R9), which is an output current limiting resistor, one end of the ninth resistor (R9) is connected to the output end of the first operational amplifier (U3), and the other end of the ninth resistor (R9) is connected to the proportional amplification module (5).

6. The continuous voltage signal segmented sampling circuit according to claim 1, characterized in that: The proportional amplification module (5) comprises a second operational amplifier (U4), an eleventh resistor (R11), a thirteenth resistor (R13), and a fourteenth resistor (R14); The inverting input terminal of the second operational amplifier (U4) is connected to the output terminal of the subtraction operation module (4), the non-inverting input terminal of the second operational amplifier (U4) is respectively connected to one end of a thirteenth resistor (R13) and a fourteenth resistor (R14), the other end of the fourteenth resistor (R14) is grounded, and the other end of the thirteenth resistor (R13) and one end of the eleventh resistor (R11) are both connected to the output terminal of the second operational amplifier (U4).

7. The continuous voltage signal segmented sampling circuit according to claim 6, characterized in that: The proportional amplification module (5) also includes a voltage stabilizing filter circuit, which includes a sixth capacitor (C6) and a voltage stabilizing diode (ZD1), one end of the sixth capacitor (C6) and a cathode end of the voltage stabilizing diode (ZD1) are connected to the other end of the eleventh resistor (R11), and one end of the sixth capacitor (C6) and an anode end of the voltage stabilizing diode (ZD1) are grounded.

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