Signal acquisition circuit and signal acquisition method

Abstract

The invention discloses a signal acquisition circuit and a signal acquisition method, and relates to the technical field of signal acquisition, the signal acquisition circuit comprises an acquisition unit, the acquisition mode of the acquisition unit is adjustable, and the acquisition unit is configured to acquire a to-be-acquired signal to obtain a first voltage signal; the filtering unit is configured to filter the first voltage signal to obtain a second voltage signal; the voltage generation unit is configured to output a first reference voltage with an adjustable amplitude; the control unit is configured to adjust an acquisition mode according to the signal type of the to-be-acquired signal, so that the acquisition unit performs voltage division processing on the to-be-acquired signal according to the corresponding acquisition mode, and acquires the second voltage signal according to the first reference voltage to obtain an initial sampling value; and adjusting the first reference voltage according to the initial sampling value, and collecting the second voltage signal according to the adjusted first reference voltage to obtain a target sampling value, thereby improving the signal collection efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of signal acquisition, and particularly relates to a signal acquisition circuit and a signal acquisition method. Background Art

[0002] In industrial control, intelligent sensing, and complex equipment monitoring systems, analog quantity acquisition, as a key link for obtaining external physical quantity information, plays a crucial role in the precise control and efficient operation of the system. There are many types of analog signals, and these different types of analog signals often have different signal characteristics, range ranges, and accuracy requirements. However, most of the acquisition circuits in the related art can only acquire a single type of analog signal, resulting in low acquisition efficiency. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems in the related art to some extent. To this end, the first object of the present invention is to propose a signal acquisition circuit. The acquisition method of the acquisition unit can be adjusted, and the control unit controls the acquisition unit according to the type of the signal to be acquired, so that the acquisition unit can acquire different types of signals to be acquired, realizing flexible acquisition of multiple types of signals, thereby improving the acquisition efficiency.

[0004] The second object of the present invention is to propose a signal acquisition method.

[0005] To achieve the above object, according to an embodiment of the first aspect of the present invention, a signal acquisition circuit is provided, including: an acquisition unit, the acquisition method of the acquisition unit is adjustable, and the acquisition unit is configured to acquire and process a signal to be acquired to obtain a first voltage signal; a filtering unit, connected to the acquisition unit, and the filtering unit is configured to filter the first voltage signal to obtain a second voltage signal; a voltage generation unit, configured to output a first reference voltage with an adjustable amplitude; a control unit, configured to adjust the acquisition method according to the signal type of the signal to be acquired, so that the acquisition unit performs voltage division processing on the signal to be acquired according to the corresponding acquisition method, and acquires the second voltage signal according to the first reference voltage to obtain an initial sampling value, and adjusts the first reference voltage according to the initial sampling value, and acquires the second voltage signal according to the adjusted first reference voltage to obtain a target sampling value.

[0006] The signal acquisition circuit according to an embodiment of the present invention includes an acquisition unit, a filtering unit, a voltage generation unit, and a control unit. The acquisition method of the acquisition unit is adjustable. The acquisition unit is configured to perform acquisition processing on a signal to be acquired to obtain a first voltage signal. The filtering unit is connected to the acquisition unit and is configured to perform filtering processing on the first voltage signal to obtain a second voltage signal. The voltage generation unit is configured to output a first reference voltage with adjustable amplitude. The control unit is configured to adjust the acquisition method according to the signal type of the signal to be acquired, so that the acquisition unit performs voltage division processing on the signal to be acquired according to the corresponding acquisition method, and acquires the second voltage signal according to the first reference voltage to obtain an initial sampling value, and adjusts the first reference voltage according to the initial sampling value, and acquires the second voltage signal according to the adjusted first reference voltage to obtain a target sampling value. Thus, the acquisition method of the acquisition unit can be adjusted, and the control unit controls the acquisition unit according to the type of the signal to be acquired, so that the acquisition unit can acquire different types of signals to be acquired, realizing flexible acquisition of multiple types of signals, thereby improving the acquisition efficiency.

[0007] According to an embodiment of the present invention, the voltage generation unit includes: a voltage generation module, the input end of the voltage generation module is adapted to be connected to a preset power supply, the output end of the voltage generation module is connected to the power input end of the control unit, and the enable end of the voltage generation module is connected to the first output end of the control unit. The voltage generation module is configured to generate a preset voltage according to the preset power supply when receiving an enable signal sent by the control unit; a controllable switch module, one end of the controllable switch module is connected to the power input end of the control unit, the other end of the controllable switch module is grounded, and the control end of the controllable switch module is connected to the second output end of the control unit. The controllable switch module is configured to provide a zero voltage to the control unit when receiving a first control signal sent by the control unit.

[0008] According to an embodiment of the present invention, the control unit includes an analog-to-digital converter. The control unit is further configured to set a second reference voltage to a first preset voltage, so that the analog-to-digital converter generates a first digital signal according to the first preset voltage and the first reference voltage, and determines an initial sampling value according to the first digital signal, and adjusts the first reference voltage or the second reference voltage according to the initial sampling value, so that the analog-to-digital converter generates a second digital signal according to the adjusted first reference voltage or the adjusted second reference voltage, and determines a target sampling value according to the second digital signal.

[0009] According to an embodiment of the present invention, the control unit is further configured to output a first control signal and stop outputting an enable signal before setting the second reference voltage to the first preset voltage, so that the analog-to-digital converter generates a first digital signal according to the first preset voltage and the zero voltage.

[0010] According to an embodiment of the present invention, the control unit is further configured to stop outputting the first control signal and output an enable signal when the initial sampling value is greater than the second preset voltage, so that the analog-to-digital converter generates a second digital signal according to the first preset voltage and the preset voltage.

[0011] According to an embodiment of the present invention, the target sampling value is calculated according to the following formula: V = (ADC / 2^n) * (Vref1 - Vref) + Vref, where ADC is the second digital signal, n is the number of bits of the analog-to-digital converter, Vref1 is the first preset voltage, and Vref is the preset voltage.

[0012] According to an embodiment of the present invention, the control unit is further configured to set the second reference voltage to the second preset voltage when the initial sampling value is less than or equal to the second preset voltage, so that the analog-to-digital converter generates a second digital signal according to the second preset voltage and the zero voltage.

[0013] According to an embodiment of the present invention, the target sampling value is calculated according to the following formula: V = (ADC / 2^n) * Vref2, where ADC is the second digital signal, n is the number of bits of the analog-to-digital converter, and Vref2 is the second preset voltage.

[0014] According to an embodiment of the present invention, the controllable switch module includes: a first resistor, one end of the first resistor is connected to the second output terminal of the control unit, and the other end of the first resistor is grounded; a first switch tube, the first end of the first switch tube is connected to the power input terminal of the control unit, the second end of the first switch tube is grounded, and the control end of the first switch tube is connected to one end of the first resistor.

[0015] According to an embodiment of the present invention, the acquisition unit includes: a second resistor, one end of the second resistor is adapted to input a signal to be acquired; a second switch tube, the first end of the second switch tube is connected to the other end of the second resistor, the second end of the second switch tube is grounded, and the control end of the second switch tube is connected to the third output terminal of the control unit; a third resistor, one end of the third resistor is connected to one end of the second resistor; a fourth resistor, one end of the fourth resistor is connected to the other end of the third resistor and has a first node, and the other end of the fourth resistor is grounded; a fifth resistor, one end of the fifth resistor is connected to the first node; a third switch tube, the first end of the third switch tube is connected to the other end of the fifth resistor, the second end of the third switch tube is grounded, and the control end of the third switch tube is connected to the fourth output terminal of the control unit.

[0016] According to an embodiment of the present invention, the control unit is further configured to turn off the second switching transistor and the third switching transistor respectively when the signal to be collected is a voltage signal and the amplitude of the signal to be collected is within a first preset range; or turn off the second switching transistor and turn on the third switching transistor when the signal to be collected is a voltage signal and the amplitude of the signal to be collected is within a second preset range, where the maximum value of the second preset range is greater than the maximum value of the first preset range; or turn on the second switching transistor and turn off the third switching transistor when the signal to be collected is a current signal and the amplitude of the signal to be collected is within a third preset range.

[0017] According to an embodiment of the present invention, the filtering unit includes: a first filtering module connected to the acquisition unit, the first filtering module being configured to perform high-frequency filtering on the first voltage signal and perform lead compensation on the first voltage signal to obtain a second voltage signal; a second filtering module connected to the first filtering module, the second filtering module being configured to perform common-mode interference suppression on the first voltage signal together with the first filtering module.

[0018] According to an embodiment of the present invention, the first filtering module includes: an operational amplifier, the positive input terminal of the operational amplifier being connected to the output terminal of the acquisition unit, and the output terminal of the operational amplifier being connected to the input terminal of the control unit; a sixth resistor, one end of the sixth resistor being connected to the negative input terminal of the operational amplifier and having a second node, and the other end of the sixth resistor being connected to the output terminal of the operational amplifier; a seventh resistor, one end of the seventh resistor being connected to the second node, and the other end of the seventh resistor being grounded; a first capacitor connected in parallel with the sixth resistor.

[0019] According to an embodiment of the present invention, the second filtering module includes: a second capacitor provided between the positive input terminal and the negative input terminal of the operational amplifier.

[0020] According to an embodiment of the present invention, the signal acquisition circuit further includes: a protection unit, the input terminal of the protection unit being adapted to input the signal to be collected, and the output terminal of the protection unit being connected to the acquisition unit, the protection unit being configured to perform overcurrent protection and overvoltage protection on the acquisition unit.

[0021] According to an embodiment of the present invention, the protection unit includes: a thermistor, one end of the thermistor being adapted to connect to the positive electrode of the signal to be collected; a first diode, one end of the first diode being connected to the other end of the thermistor, and the other end of the first diode being grounded and adapted to connect to the negative electrode of the signal to be collected; a third capacitor connected in parallel with the first diode.

[0022] To achieve the above object, according to an embodiment of the second aspect of the present invention, a signal acquisition method is proposed, which is applied to a signal acquisition circuit. The signal acquisition circuit includes an acquisition unit, a filtering unit, and a voltage generation unit. The voltage division method of the acquisition unit is adjustable. The acquisition unit is configured to perform voltage division processing on the signal to be acquired to obtain a first voltage signal. The filtering unit is connected to the acquisition unit and is configured to perform filtering processing on the first voltage signal to obtain a second voltage signal. The voltage generation unit is configured to output a first reference voltage with adjustable amplitude. The method includes: adjusting the voltage division method according to the signal type of the signal to be acquired, so that the acquisition unit performs voltage division processing on the signal to be acquired according to the corresponding voltage division method; acquiring the second voltage signal according to the first reference voltage to obtain an initial sampling value; adjusting the first reference voltage according to the initial sampling value, and acquiring the second voltage signal according to the adjusted first reference voltage to obtain a target sampling value.

[0023] According to the signal acquisition method of the embodiment of the present invention, the acquisition method is adjusted according to the signal type of the signal to be acquired, so that the acquisition unit performs voltage division processing on the signal to be acquired according to the corresponding acquisition method, and acquires the second voltage signal according to the first reference voltage to obtain an initial sampling value, and adjusts the first reference voltage according to the initial sampling value, and acquires the second voltage signal according to the adjusted first reference voltage to obtain a target sampling value. Wherein, the signal acquisition circuit includes an acquisition unit, a filtering unit, and a voltage generation unit. The acquisition method of the acquisition unit is adjustable. The acquisition unit is configured to perform acquisition processing on the signal to be acquired to obtain a first voltage signal. The filtering unit is connected to the acquisition unit and is configured to perform filtering processing on the first voltage signal to obtain a second voltage signal. The voltage generation unit is configured to output a first reference voltage with adjustable amplitude. Thus, the acquisition method of the acquisition unit can be adjusted, and the control unit controls the acquisition unit according to the type of the signal to be acquired, so that the acquisition unit can acquire different types of signals to be acquired, realizing flexible acquisition of multi-type signals, thereby improving the acquisition efficiency.

[0024] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. Description of the Drawings

[0025] Figure 1 is a schematic structural diagram of a signal acquisition circuit according to an embodiment of the present invention; Figure 2 is a circuit diagram of an acquisition unit according to an embodiment of the present invention; Figure 3 is a timing diagram when the signal to be acquired is a voltage signal of 0-5V according to an embodiment of the present invention; Figure 4 is a timing diagram when the signal to be collected is a voltage signal of 0 - 10V according to an embodiment of the present invention; Figure 5 is a timing diagram when the signal to be collected is a current signal of 4 - 20mA according to an embodiment of the present invention; Figure 6 is a circuit diagram of a voltage generation unit according to an embodiment of the present invention; Figure 7 is a schematic flowchart of an adjustment method for a reference voltage according to an embodiment of the present invention; Figure 8 is a circuit diagram of a filtering unit and a protection unit according to an embodiment of the present invention; Figure 9 is a schematic flowchart of a signal acquisition method according to an embodiment of the present invention. Detailed Embodiments

[0026] The embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described by referring to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0027] Most of the acquisition circuits in the related art can only collect a single type of analog signal, lack targeted adaptation to different signal types, cannot flexibly collect analog signals, and require more sampling ports. Further, most of the acquisition circuits in the related art use relays for switching. Since the power consumption of relays is large (it requires consuming dozens of milliamperes of current to work stably), the lifespan is limited (the lifespan of relays is about 50,000 times), and the anti-interference ability is poor (there is electromagnetic switching during the operation of relays, which brings interference to the power network and signals), therefore, the acquisition circuits in the related art have problems such as large acquisition power consumption, low lifespan, and poor anti-interference ability.

[0028] Based on this, the embodiments of the present invention provide a signal acquisition circuit and a signal acquisition method. The acquisition method of the acquisition unit can be adjusted, and the control unit controls the acquisition unit according to the type of the signal to be collected, so that the acquisition unit can collect different types of signals to be collected, realizing flexible acquisition of multiple types of signals, thereby improving the acquisition efficiency.

[0029] The signal acquisition circuit and the signal acquisition method of the embodiments of the present invention will be described below with reference to the accompanying drawings.

[0030] Figure 1 is a schematic structural diagram of a signal acquisition circuit according to an embodiment of the present invention. As Figure 1As shown, the signal acquisition circuit includes: an acquisition unit 10, a filtering unit 20, a voltage generation unit 30, and a control unit 40.

[0031] Among them, the acquisition method of the acquisition unit 10 is adjustable. The acquisition unit 10 is configured to acquire and process the signal to be acquired to obtain a first voltage signal. The filtering unit 20 is connected to the acquisition unit 10 and is configured to filter the first voltage signal to obtain a second voltage signal. The voltage generation unit 30 is configured to output a first reference voltage with adjustable amplitude. The control unit 40 is configured to adjust the acquisition method according to the signal type of the signal to be acquired, so that the acquisition unit 10 performs voltage division processing on the signal to be acquired according to the corresponding acquisition method, and acquires the second voltage signal according to the first reference voltage to obtain an initial sampling value, and adjusts the first reference voltage according to the initial sampling value, and acquires the second voltage signal according to the adjusted first reference voltage to obtain a target sampling value.

[0032] Specifically, there are three types of signal types of the signal to be acquired. The first type of signal to be acquired is a voltage signal, and the amplitude of the first type of signal to be acquired is within a first preset range (for example, 0 - 5V). The second type of signal to be acquired is a voltage signal, and the amplitude of the second type of signal to be acquired is within a second preset range (for example, 0 - 10V). The third type of signal to be acquired is a current signal, and the amplitude of the third type of signal to be acquired is within a third preset range (for example, 4 - 20mA). Both the first type of signal to be acquired and the second type of signal to be acquired are voltage signals, but the signal amplitudes of the two types of signals are different, and different acquisition methods need to be set for the two types of signals so that the first voltage signal can meet the working range of the sampling port of the control unit 40. The third type of signal to be acquired is a current signal, and the current signal needs to be converted into a voltage signal, so the acquisition method required for the third type of signal to be acquired is different from both the first type of signal to be acquired and the second type of signal to be acquired. The acquisition unit 10 sets different acquisition methods for three types of analog signals. The control unit 40 adjusts the acquisition method of the acquisition unit 10 according to the signal type of the signal to be acquired, and the acquisition unit 10 uses the corresponding acquisition method for acquisition to obtain a first voltage signal. The filtering unit 20 filters the first voltage signal to obtain a second voltage signal and provides the second voltage signal to the control unit 40. Therefore, only one sampling port of the control unit 40 is occupied.

[0033] Furthermore, the signal acquisition circuit further includes a voltage generation unit 30. The control unit 40 performs a first sampling on the second voltage signal based on the first reference voltage output by the voltage generation unit 30 to obtain an initial sampling value. If the voltage value selected for the first reference voltage is not appropriate, the resolution of the initial sampling value is low, and the first reference voltage needs to be adjusted, and then the second voltage signal is sampled again to obtain a target sampling value with higher resolution.

[0034] In the above embodiments, the acquisition mode of the acquisition unit can be adjusted according to different signal types to acquire different types of signals to be acquired, realizing flexible acquisition of multiple types of signals, thereby improving the acquisition efficiency. Further, because the acquisition unit realizes flexible acquisition of multiple types of signals, only one sampling port of the control unit needs to be occupied, thus solving the problem of insufficient sampling ports. Moreover, the first voltage signal is filtered by the filtering unit, which can effectively suppress electromagnetic interference and improve the anti-interference ability of the signal acquisition circuit, thereby enhancing the reliability of signal acquisition. In addition, the control unit can also adjust the first reference voltage according to the initial sampling value, thereby improving the acquisition resolution to output a target initial value with higher accuracy.

[0035] In some embodiments, as Figure 2 shown, the acquisition unit 10 includes: a second resistor R2, a second switching transistor Q2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a third switching transistor Q3. Among them, one end of the second resistor R2 is adapted to input the signal to be acquired; the first end of the second switching transistor Q2 is connected to the other end of the second resistor R2, the second end of the second switching transistor Q2 is grounded, and the control end of the second switching transistor Q2 is connected to the third output end of the control unit 40; one end of the third resistor R3 is connected to one end of the second resistor R2; one end of the fourth resistor R4 is connected to the other end of the third resistor R3 and has a first node J1, and the other end of the fourth resistor R4 is grounded; one end of the fifth resistor R5 is connected to the first node J1; the first end of the third switching transistor Q3 is connected to the other end of the fifth resistor R5, the second end of the third switching transistor Q3 is grounded, and the control end of the third switching transistor Q3 is connected to the fourth output end of the control unit 40.

[0036] Specifically, the control end of the second switching transistor Q2 is adapted to input the second control signal AI_ON1 of the control unit 40, and the control end of the third switching transistor Q3 is adapted to input the third control signal AI_ON2 of the control unit 40. When the second switching transistor Q2 and the third switching transistor Q3 are respectively in the off state, the third resistor R3 and the fourth resistor R4 acquire the signal to be acquired; when the second switching transistor Q2 is in the off state and the third switching transistor Q3 is in the on state, the third resistor R3, the fourth resistor R4, and the fifth resistor R5 acquire the signal to be acquired; when the second switching transistor Q2 is in the on state and the third switching transistor Q3 is in the off state, the second resistor R2, the third resistor R3, and the fourth resistor R4 acquire the signal to be acquired. Therefore, by controlling the switching states of the second switching transistor Q2 and the third switching transistor Q3, the circuit connection mode of the acquisition unit 10 can be adjusted, thereby realizing the adjustment of the connection mode of the acquisition unit 10.

[0037] It should be noted that the second switching transistor Q2 and the third switching transistor Q3 are respectively NMOS (N-Metal-Oxide-Semiconductor), but are not limited to NMOS, and can also be other devices, such as triodes, etc.

[0038] In the above embodiment, the acquisition unit is composed of a switching transistor and a resistor. The switching transistor has low power consumption and a long service life. Moreover, compared with a relay, when the switching transistor is switched, there is no electromagnetic switching, so it will not interfere with the signal acquisition circuit, thereby reducing the cost of the signal acquisition circuit, improving the service life of the signal acquisition circuit, and further improving the reliability of the signal acquisition circuit.

[0039] In some embodiments, the control unit 40 is further configured to, when the signal to be acquired is a voltage signal and the amplitude of the signal to be acquired is within a first preset range, control the second switching transistor Q2 and the third switching transistor Q3 to be turned off respectively; or when the signal to be acquired is a voltage signal and the amplitude of the signal to be acquired is within a second preset range, control the second switching transistor Q2 to be turned off and control the third switching transistor Q3 to be turned on, where the maximum value of the second preset range is greater than the maximum value of the first preset range; or when the signal to be acquired is a current signal and the amplitude of the signal to be acquired is within a third preset range, control the second switching transistor Q2 to be turned on and control the third switching transistor Q3 to be turned off.

[0040] Specifically, when the signal to be acquired is a voltage signal and the amplitude of the signal to be acquired is within the first preset range, the signal to be acquired is an analog signal as shown in Figure 3 The analog signal is a voltage signal and the amplitude range is 0 - 5V. When the signal to be acquired is input, the control unit 40 outputs low-level signals to the control terminals of the second switching transistor Q2 and the third switching transistor Q3 respectively, so that the second switching transistor Q2 and the third switching transistor Q3 are turned off respectively, and the third resistor R3 and the fourth resistor R4 divide the voltage of the signal to be acquired to obtain a first voltage signal Vo1. The first voltage signal Vo1 is vin*R4 / (R3 + R4), where vin is the signal to be acquired; When the signal to be acquired is a voltage signal and the amplitude of the signal to be acquired is within the second preset range, the signal to be acquired is as shown in Figure 4The analog signal shown is a voltage signal with an amplitude range of 0 - 10V. When the signal to be acquired is input, the control unit 40 outputs a low-level signal to the control terminal of the second switching transistor Q2 and a high-level signal to the control terminal of the third switching transistor Q3, so that the second switching transistor Q2 is turned off and the third switching transistor Q3 is turned on. The third resistor R3, the fourth resistor R4, and the fifth resistor R5 divide the signal to be acquired to obtain a first voltage signal Vo1. The first voltage signal Vo1 is vin*(R4 / / R5) / [R3+(R4 / / R5)], where vin is the signal to be acquired. When the signal to be acquired is a current signal and the amplitude of the signal to be acquired is within the third preset range, the signal to be acquired is as Figure 5 shown. The analog signal is a current signal with an amplitude range of 4 - 20mA. When the signal to be acquired is input, the control unit 40 outputs a high-level signal to the control terminal of the second switching transistor Q2 and a low-level signal to the control terminal of the third switching transistor Q3, so that the second switching transistor Q2 is turned on and the third switching transistor Q3 is turned off. The second resistor R2 converts the signal to be acquired from a current signal to a voltage signal, and then the third resistor R3 and the fourth resistor R4 divide the voltage to obtain a first voltage signal Vo1. The first voltage signal Vo1 is I*R2*R4 / (R3+R4), where I is the signal to be acquired.

[0041] Further, the resistance values of the second resistor R2, the third resistor R3, and the fourth resistor R4 need to be set according to the working range of the sampling port of the control unit 40. Taking Figures 3 to 5 shown as an example, assuming the working range of the sampling port of the control unit 40 is 0 - 3.3V, therefore, the range of the first voltage signal Vo1 is between 0 - 2.5V.

[0042] In some embodiments, as Figure 6 shown, the voltage generation unit includes: a voltage generation module 31 and a controllable switch module 32. Among them, the input end of the voltage generation module 31 is adapted to be connected to a preset power supply Vcc, the output end of the voltage generation module 31 is connected to the power input end VREF- of the control unit 40, the enable end ENABLE of the voltage generation module 31 is connected to the first output end of the control unit 40, and the voltage generation module 31 is configured to generate a preset voltage Vref according to the preset power supply Vcc when receiving the enable signal REF_ON1 sent by the control unit 40; one end of the controllable switch module 32 is connected to the power input end VREF- of the control unit 40, the other end of the controllable switch module 32 is grounded, the control end of the controllable switch module 32 is connected to the second output end of the control unit 40, and the controllable switch module 32 is configured to provide a zero voltage to the control unit 40 when receiving the first control signal VSS_ON1 sent by the control unit 40.

[0043] Specifically, the control unit 40 outputs an enable signal REF_ON1 to the voltage generation module 31. The voltage generation module 31 performs voltage conversion on the preset power supply Vcc to generate a preset voltage Vref, and supplies the preset voltage Vref to the power input terminal VREF- of the control unit 40. One end of the controllable switch module 32 is also connected to the power input terminal VREF- of the control unit 40. When the controllable switch module 32 receives the first control signal VSS_ON1, the controllable switch module 32 pulls the power input terminal VREF- to a low level. Therefore, the voltage generation module 31 can output the preset voltage Vref or zero voltage, thereby realizing the adjustment of the first reference voltage.

[0044] In an alternative embodiment, the voltage generation module 31 includes a reference voltage source chip 311. The power input pin VIN of the reference voltage source chip 311 is adapted to be connected to the preset power supply Vcc. The enable pin ENABLE of the reference voltage source chip 311 is connected to the first output terminal of the control unit 40. The ground drive pin GND_FORCE and the ground sense pin GND_SENSE of the reference voltage source chip 311 are respectively grounded. The voltage output pin VOUT_FORCE and the output voltage sense pin VOUT_SENSE of the reference voltage source chip 311 are the output terminals of the voltage generation module 31.

[0045] In some embodiments, as Figure 6 shown, the control unit 40 includes an analog-to-digital converter (not shown). The control unit 40 is further configured to set the second reference voltage to a first preset voltage, so that the analog-to-digital converter generates a first digital signal according to the first preset voltage and the first reference voltage, and determines an initial sampling value according to the first digital signal, and adjusts the first reference voltage or the second reference voltage according to the initial sampling value, so that the analog-to-digital converter generates a second digital signal according to the adjusted first reference voltage or the adjusted second reference voltage, and determines a target sampling value according to the second digital signal.

[0046] Specifically, the second reference voltage is the internal reference voltage of the control unit 40. The analog-to-digital converter performs analog-to-digital conversion on the second voltage signal Vo2 based on the voltage difference between the second reference voltage and the first reference voltage to generate a digital signal. Then, the control unit 40 determines the sampling value according to the first reference voltage, the second reference voltage, and the digital signal. It should be noted that the second reference voltage needs to be greater than the maximum value of the second voltage signal Vo2 so as to achieve accurate sampling of the second voltage signal Vo2. Therefore, during the first sampling, in order to avoid the situation where the second voltage signal Vo2 exceeds the second reference voltage, the second reference voltage needs to be set to a relatively large first preset voltage. There is a correlation between the resolution of the analog-to-digital converter and the voltage difference. Assuming that the analog-to-digital converter is a 12-bit analog-to-digital converter with a resolution of 4096, its minimum measurable signal is the ratio of the voltage difference to 4096. Therefore, the larger the voltage difference, the larger the minimum measurable signal, and the lower the accuracy of the analog-to-digital converter. Therefore, the control unit 40 adjusts the first reference voltage or the second reference voltage according to the initial sampling value to adjust the voltage difference, and then samples the subsequent input second voltage signal Vo2 according to the adjusted voltage difference, so as to obtain a target sampling value with higher accuracy.

[0047] In some embodiments, the control unit 40 is further configured to output a first control signal VSS_ON1 and stop outputting the enable signal REF_ON1 before setting the second reference voltage to the first preset voltage, so that the analog-to-digital converter generates a first digital signal according to the first preset voltage and the zero voltage.

[0048] Specifically, during the first sampling of the second voltage signal Vo2, since the control unit 40 does not obtain the amplitude information of the second voltage signal Vo2, the second voltage signal Vo2 is first sampled with the maximum reference voltage (i.e., the largest voltage difference) to avoid the second voltage signal Vo2 exceeding the sampling range. Therefore, before setting the second reference voltage to the first preset voltage, the control unit 40 outputs the first control signal VSS_ON1 to enable the controllable switch module 32 to connect the power input terminal VREF- of the control unit 40 to the ground. Therefore, the voltage difference is the first preset voltage. At this time, the voltage generation module 31 does not need to output the preset voltage Vref, so the control unit 40 simultaneously stops outputting the enable signal REF_ON1 to make the voltage generation module 31 stop working, thereby reducing the power consumption of the signal acquisition circuit.

[0049] In some embodiments, the control unit 40 is further configured to stop outputting the first control signal VSS_ON1 and output an enable signal REF_ON1 when the initial sampling value is greater than a second preset voltage, so that the analog-to-digital converter generates a second digital signal based on a first preset voltage and a preset voltage Vref, where the second preset voltage is less than the first preset voltage.

[0050] Specifically, the second preset voltage is also the internal reference voltage of the control unit 40, and the second preset voltage is less than the first preset voltage. When the initial sampling value is greater than the second preset voltage, it indicates that the amplitude of the second voltage signal Vo2 is between the second preset voltage and the first preset voltage. Therefore, by increasing the first reference voltage, the voltage difference can be reduced, thereby reducing the minimum measurable signal of the analog-to-digital converter and further improving the accuracy of the analog-to-digital converter. The control unit 40 stops outputting the first control signal VSS_ON1 to disconnect the connection between the power input terminal VREF- of the control unit 40 and the ground, and outputs an enable signal REF_ON1 to enable the voltage generation module 31 to start working and output the preset voltage Vref to the power input terminal VREF- of the control unit 40. Therefore, the voltage difference is the difference between the first preset voltage and the preset voltage Vref. Then, the analog-to-digital converter samples the subsequent input second voltage signal Vo2 based on the first preset voltage and the preset voltage Vref to obtain a second digital signal, and the control unit 40 determines the target sampling value based on the second digital signal.

[0051] In some embodiments, the target sampling value is calculated according to the following formula (1): V = (ADC / 2^n) * (Vref1 - Vref) + Vref (1) where ADC is the second digital signal, n is the number of bits of the analog-to-digital converter, Vref1 is the first preset voltage, and Vref is the preset voltage.

[0052] It can be understood that since the analog-to-digital converter samples the second voltage signal Vo2 based on the first preset voltage Vref1 and the preset voltage Vref, the control unit 40 also calculates the target sampling value based on the first preset voltage Vref1 and the preset voltage Vref when determining the target sampling value according to the analog-to-digital converter.

[0053] In some embodiments, the control unit 40 is further configured to set the second reference voltage to the second preset voltage when the initial sampling value is less than or equal to the second preset voltage, so that the analog-to-digital converter generates a second digital signal based on the second preset voltage and zero voltage.

[0054] Specifically, when the initial sampling value is less than or equal to the second preset voltage, it indicates that the amplitude of the second voltage signal Vo2 is less than or equal to the second preset voltage. Therefore, by reducing the second reference voltage, the voltage difference can be decreased, thereby reducing the minimum measurable signal of the analog-to-digital converter and further improving the accuracy of the analog-to-digital converter. The control unit 40 sets the second reference voltage to the second preset voltage. At this time, the control unit 40 still outputs the first control signal VSS_ON1 and stops outputting the enable signal REF_ON1. In this way, the power input terminal VREF- of the control unit 40 is still connected to the ground. Therefore, the voltage difference is the difference between the second preset voltage and the zero voltage. Then, the analog-to-digital converter samples the subsequent input second voltage signal Vo2 based on the second preset voltage and the zero voltage to obtain a second digital signal, and the control unit 40 determines the target sampling value based on the second digital signal.

[0055] In some embodiments, the target sampling value is calculated according to the following formula (2): V = (ADC / 2^n) * Vref2 (2) Where ADC is the second digital signal, n is the number of bits of the analog-to-digital converter, and Vref2 is the second preset voltage.

[0056] Similarly, since the analog-to-digital converter samples the second voltage signal Vo2 based on the second preset voltage Vref2 and the zero voltage, the control unit 40 also calculates the target sampling value based on the second preset voltage Vref2 and the zero voltage when determining the target sampling value according to the analog-to-digital converter.

[0057] It should be noted that the calculation method of the initial sampling value is similar to the calculation method of the target sampling value shown in formula (2), that is, the initial sampling value can be obtained by modifying the second preset voltage Vref2 to the first preset voltage Vref1.

[0058] For example, such as Figure 7As shown, assume that the first preset voltage is the power supply voltage (3.3V), the second preset voltage and the preset voltage are both 1.5V, and the number of bits n of the analog-to-digital converter is 12. Before collecting the second voltage signal, the control unit outputs a first control signal and stops outputting the enable signal to supply zero voltage to the power input terminal of the control unit, and then sets the second reference voltage to the power supply voltage. The analog-to-digital converter samples the second voltage signal to obtain a first digital signal, and the control unit calculates an initial sampling value based on the first digital signal. If the initial sampling value is less than or equal to the second preset voltage (1.5V), the second reference voltage is adjusted to 1.5V, and the target sampling value is calculated based on the second digital signal, where the target sampling value is (ADC / 2^12)*1.5; if the initial sampling value is greater than the second preset voltage (1.5V), the first control signal is stopped from being output, and the enable signal is output to adjust the first reference voltage to 1.5V and keep the second reference voltage unchanged, and the target sampling value is (ADC / 2^12)*(3.3 - 1.5)+1.5. Therefore, before the reference voltage is adjusted, the resolution of the analog-to-digital converter is 4096, and after the reference voltage is adjusted, the resolution of the analog-to-digital converter is 4096*2 = 8192, and the measurement accuracy of the analog-to-digital converter is doubled.

[0059] In the above embodiment, the first reference voltage or the second reference voltage of the analog-to-digital converter is adjusted according to the initial sampling value, thereby improving the sampling accuracy of the control unit.

[0060] In some embodiments, as Figure 6 shown, the controllable switch module 32 includes: a first resistor R1 and a first switching transistor Q1. Wherein, one end of the first resistor R1 is connected to the second output terminal of the control unit 40, and the other end of the first resistor R1 is grounded; the first end of the first switching transistor Q1 is connected to the power input terminal VREF- of the control unit 40, the second end of the first switching transistor Q1 is grounded, and the control end of the first switching transistor Q1 is connected to one end of the first resistor R1.

[0061] Exemplarily, the first switching transistor Q1 can also be an NMOS transistor, and the first control signal VSS_ON1 is a high-level signal. The control unit 40 outputs the first control signal VSS_ON1 to the control end of the first switching transistor Q1, thereby pulling the power input terminal VREF- of the control unit 40 to a low level. When the control unit 40 stops outputting the first control signal VSS_ON1, the control end of the first switching transistor Q1 is pulled to a low level by the first resistor R1. Therefore, the first switching transistor Q1 remains in the off state, so that the power input terminal VREF- of the control unit 40 is disconnected from the ground.

[0062] In some embodiments, as Figure 8As shown, the filtering unit 20 includes: a first filtering module 21 and a second filtering module 22. Among them, the first filtering module 21 is connected to the acquisition unit 10, and the first filtering module 21 is configured to perform high-frequency filtering on the first voltage signal and perform lead compensation on the first voltage signal to obtain a second voltage signal; the second filtering module 22 is connected to the first filtering module 21, and the second filtering module 22 is configured to perform common-mode interference suppression on the first voltage signal together with the first filtering module 21.

[0063] It can be understood that the signal acquisition circuit may be affected by external interference, resulting in noise signals in the first voltage signal. Therefore, the first filtering module 21 can filter out the high-frequency noise in the first voltage signal. In the related art, due to reasons such as wiring and load, the filtering circuit will generate self-excited oscillation, and the first filtering module 21 of this embodiment can also perform lead compensation to destroy the self-excited oscillation condition, thereby avoiding the occurrence of high-frequency oscillation and further improving the stability of the output signal. Further, the second filtering module 22 also performs common-mode interference suppression together with the first filtering module 21, thereby further improving the stability of the output signal.

[0064] In some embodiments, as Figure 8 shown, the first filtering module 21 includes: an operational amplifier OP, a sixth resistor R6, a seventh resistor R7, and a first capacitor C1. Among them, the positive input terminal of the operational amplifier OP is connected to the output terminal of the acquisition unit 10, and the output terminal of the operational amplifier OP is connected to the input terminal of the control unit 40; one end of the sixth resistor R6 is connected to the negative input terminal of the operational amplifier OP and has a second node J2, and the other end of the sixth resistor R6 is connected to the output terminal of the operational amplifier OP; one end of the seventh resistor R7 is connected to the second node J2, and the other end of the seventh resistor R7 is grounded; the first capacitor C1 is connected in parallel with the sixth resistor R6.

[0065] Specifically, when high-frequency noise is introduced into the signal acquisition circuit, the noise gain is as shown in formula (3): NG = 1 + {1 / [ω(C1 / / R6)]} / R7 (3) where NG is the noise gain and ω is the angular frequency.

[0066] When the noise frequency increases, the molecules decrease, thereby reducing the overall noise gain. In the operational amplifier circuit, when the loop amplification factor |AF| > 1, due to reasons such as wiring and load, there are parasitic capacitances and load capacitances between the input terminal and the output terminal, generating a second-order filter circuit to make the feedback phase -180°, and the circuit generates self-excited oscillation. Therefore, a first capacitor C1 is connected in parallel with the sixth resistor R6 to make the phase less than -180° and destroy the self-excited oscillation condition; moreover, because of the input high-impedance and output low-impedance characteristics of the operational amplifier OP, the operational amplifier OP can perform load isolation to ensure that the signal does not change with the load parameters, making the output waveform stable and reliable.

[0067] In some embodiments, as Figure 8 shown, the second filtering module 22 includes: a second capacitor C2, and the second capacitor C2 is arranged between the positive input terminal and the negative input terminal of the operational amplifier OP.

[0068] Specifically, there is an instantaneous interference signal at the positive input terminal of the operational amplifier OP. Therefore, the voltage at the positive input terminal is higher than the voltage at the negative input terminal, and an interference signal will be instantaneously generated at the output terminal of the operational amplifier OP. However, due to the existence of the second capacitor C2, the voltage across the second capacitor C2 cannot change suddenly. Therefore, the interference signal at the output terminal of the operational amplifier OP will quickly be completely applied to the negative input terminal. Therefore, the interference signal at the positive input terminal and the interference signal at the negative input terminal of the operational amplifier OP will cancel each other out, playing a role in suppressing common-mode interference and making the output signal more stable.

[0069] In an alternative embodiment, the filtering unit 20 further includes a third filtering module 23. The third filtering module 23 includes an eighth resistor R8 and a fourth capacitor C4. One end of the eighth resistor R8 is connected to the output terminal of the acquisition unit 10, and the other end of the eighth resistor R8 is respectively connected to one end of the fourth capacitor C4 and the positive input terminal of the operational amplifier OP, and the other end of the fourth capacitor C4 is grounded. By selecting the resistance value of the eighth resistor R8 and the capacitance value of the fourth capacitor C4, the cut-off frequency fp can be set, where the cut-off frequency fp is 1 / (2πR8C3). The gain Au of the third filtering module 23 is 1 / (1 + jf / fp), where the larger the interference frequency f, the smaller the gain Au, and the better the filtering effect.

[0070] Further, the filtering unit 20 further includes a second diode D2, a third diode D3, and a fourth diode D4. Among them, the second diode D2 is a transient voltage suppression diode. One end of the second diode D2 is connected to the output end of the acquisition unit 10, and the other end of the second diode D2 is grounded. The cathode of the third diode D3 is adapted to be connected to a preset power supply Vcc, the anode of the third diode D3 is connected to the output end of the operational amplifier OP, the cathode of the fourth diode D4 is connected to the output end of the operational amplifier OP, and the anode of the fourth diode D4 is grounded. The second diode D2 can lead the overvoltage to the ground when the circuit is subjected to overvoltage and overcurrent shocks, thereby protecting the sensitive components of the circuit. The third diode D3 and the fourth diode D4 can clamp the voltage signal output by the operational amplifier OP when it is too large or too small, so as to prevent the control unit 40 from being impacted.

[0071] In some embodiments, as Figure 8 shown, the signal acquisition circuit further includes: a protection unit 50. The input end of the protection unit 50 is adapted to input a signal to be acquired, the output end of the protection unit 50 is connected to the acquisition unit 10, and the protection unit 50 is configured to perform overcurrent protection and overvoltage protection on the acquisition unit 10.

[0072] It can be understood that the acquisition unit 10 is the core part of the signal acquisition circuit. Therefore, it is necessary to set the protection unit 50 before the acquisition unit 10 to perform overcurrent protection and overvoltage protection on the acquisition unit 10, so as to ensure that it works within a safe current and voltage range, thereby extending the service life of the signal acquisition circuit and further improving the reliability of the signal acquisition circuit.

[0073] Optionally, in some embodiments, as Figure 8 shown, the protection unit 50 includes: a thermistor F1, a first diode D1, and a third capacitor C3. One end of the thermistor F1 is adapted to be connected to the positive electrode IN+ of the signal to be acquired; one end of the first diode D1 is connected to the other end of the thermistor F1, the other end of the first diode D1 is grounded, and is adapted to be connected to the negative electrode IN- of the signal to be acquired; the third capacitor C3 is connected in parallel with the first diode D1.

[0074] Specifically, the thermistor F1 is a positive temperature coefficient thermistor F1, and the first diode D1 is a transient voltage suppression diode. By using the two in combination according to their response times and parameter characteristics, overcurrent protection and overvoltage protection can be effectively performed. When the circuit is subjected to overvoltage and overcurrent shocks, the reverse breakdown voltage of the first diode D1 will respond quickly and lead the overvoltage to the ground, thereby protecting the sensitive components of the circuit. The overvoltage shock may continuously cause the current to increase sharply, exceeding the rated current range of the circuit components. At this time, the current flowing through the thermistor F1 is greater than the operating current of the thermistor F1, and the impedance of the thermistor F1 will rise rapidly, restricting the increase of the current, thereby preventing the circuit from being subjected to overcurrent shocks.

[0075] In summary, for the signal acquisition circuit according to the embodiments of the present invention, the acquisition method of the acquisition unit can be adjusted according to different signal types to acquire different types of signals to be acquired, realizing flexible acquisition of multi-type signals, thereby improving the acquisition efficiency. Since the acquisition unit realizes flexible acquisition of multi-type signals, only one sampling port of the control unit is occupied, thus solving the problem of insufficient sampling ports. Moreover, by filtering the first voltage signal through the filtering unit, electromagnetic interference can be effectively suppressed, and the anti-interference ability of the signal acquisition circuit is improved, thereby enhancing the reliability of signal acquisition. In addition, the control unit can also adjust the first reference voltage according to the initial sampling value, thereby improving the acquisition resolution to output a target initial value with higher precision. Further, the acquisition unit is composed of a switching tube and a resistor. The switching tube has low power consumption and a long service life. Moreover, compared with a relay, there is no electromagnetic switching when the switching tube is switched, so it will not interfere with the signal acquisition circuit, thereby reducing the cost of the signal acquisition circuit, increasing the service life of the signal acquisition circuit, and further enhancing the reliability of the signal acquisition circuit.

[0076] Corresponding to the above embodiments, an embodiment of the present invention also provides a signal acquisition method. The signal acquisition method is applied to a signal acquisition circuit as shown in Figure 1 The signal acquisition circuit includes an acquisition unit 10, a filtering unit 20, and a voltage generation unit 30. The voltage division method of the acquisition unit 10 is adjustable. The acquisition unit 10 is configured to perform voltage division processing on the signal to be acquired to obtain a first voltage signal. The filtering unit 20 is connected to the acquisition unit 10. The filtering unit 20 is configured to perform filtering processing on the first voltage signal to obtain a second voltage signal. The voltage generation unit 30 is configured to output a first reference voltage with adjustable amplitude. As shown in Figure 9 The signal acquisition method includes: S201, adjust the voltage division method according to the signal type of the signal to be acquired, so that the acquisition unit performs voltage division processing on the signal to be acquired according to the corresponding voltage division method.

[0077] S202, acquire the second voltage signal according to the first reference voltage to obtain an initial sampling value.

[0078] S203, adjust the first reference voltage according to the initial sampling value, and acquire the second voltage signal according to the adjusted first reference voltage to obtain a target sampling value.

[0079] In some embodiments, the voltage generation unit 30 includes a voltage generation module 31 and a controllable switch module 32. Among them, the input end of the voltage generation module 31 is adapted to be connected to a preset power supply Vcc. The voltage generation module 31 is configured to generate a preset voltage Vref according to the preset power supply Vcc when receiving an enable signal REF_ON1. The other end of the controllable switch module 32 is grounded. The controllable switch module 32 is configured to provide a zero voltage when receiving a first control signal VSS_ON1. The signal acquisition circuit further includes an analog-to-digital converter. The method further includes: setting a second reference voltage to a first preset voltage so that the analog-to-digital converter generates a first digital signal according to the first preset voltage and a first reference voltage, determining an initial sampling value according to the first digital signal, and adjusting the first reference voltage or the second reference voltage according to the initial sampling value so that the analog-to-digital converter generates a second digital signal according to the adjusted first reference voltage or the adjusted second reference voltage, and determining a target sampling value according to the second digital signal.

[0080] In some embodiments, before setting the second reference voltage to the first preset voltage, the method further includes: outputting a first control signal and stopping outputting the enable signal so that the analog-to-digital converter generates a first digital signal according to the first preset voltage and the zero voltage.

[0081] In some embodiments, adjusting the first reference voltage or the second reference voltage according to the initial sampling value includes: when the initial sampling value is greater than a second preset voltage, stopping outputting the first control signal and outputting the enable signal so that the analog-to-digital converter generates a second digital signal according to the first preset voltage and the preset voltage.

[0082] In some embodiments, the target sampling value is calculated according to the following formula: V=(ADC / 2^n)*(Vref1-Vref)+Vref Where ADC is the second digital signal, n is the number of bits of the analog-to-digital converter, Vref1 is the first preset voltage, and Vref is the preset voltage.

[0083] In some embodiments, adjusting the first reference voltage or the second reference voltage according to the initial sampling value includes: when the initial sampling value is less than or equal to the second preset voltage, setting the second reference voltage to the second preset voltage so that the analog-to-digital converter generates a second digital signal according to the second preset voltage and the zero voltage.

[0084] In some embodiments, the target sampling value is calculated according to the following formula: V=(ADC / 2^n)*Vref2 Where ADC is the second digital signal, n is the number of bits of the analog-to-digital converter, and Vref2 is the second preset voltage.

[0085] In some embodiments, the acquisition unit 10 includes: a second resistor R2, a second switching transistor Q2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a third switching transistor Q3. Wherein, one end of the second resistor R2 is adapted to input a signal to be acquired, the first end of the second switching transistor Q2 is connected to the other end of the second resistor R2, the second end of the second switching transistor Q2 is grounded, one end of the third resistor R3 is connected to one end of the second resistor R2, one end of the fourth resistor R4 is connected to the other end of the third resistor R3 and has a first node J1, the other end of the fourth resistor R4 is grounded, and one end of the fifth resistor R5 is connected to the first node J1; the first end of the third switching transistor Q3 is connected to the other end of the fifth resistor R5, and the second end of the third switching transistor Q3 is grounded. Adjusting the voltage division method according to the signal type of the signal to be acquired includes: when the signal to be acquired is a voltage signal and the amplitude of the signal to be acquired is within a first preset range, controlling the second switching transistor and the third switching transistor to be turned off respectively; or when the signal to be acquired is a voltage signal and the amplitude of the signal to be acquired is within a second preset range, controlling the second switching transistor to be turned off and controlling the third switching transistor to be turned on, wherein the maximum value of the second preset range is greater than the maximum value of the first preset range; or when the signal to be acquired is a current signal and the amplitude of the signal to be acquired is within a third preset range, controlling the second switching transistor to be turned on and controlling the third switching transistor to be turned off.

[0086] It should be noted that the specific implementation manners of the signal acquisition method in the embodiments of the present invention correspond one by one to the specific implementation manners of the signal acquisition circuit in the foregoing embodiments of the present invention, and will not be elaborated herein.

[0087] According to the signal acquisition method of the embodiments of the present invention, the acquisition method is adjusted according to the signal type of the signal to be acquired, so that the acquisition unit performs voltage division processing on the signal to be acquired according to the corresponding acquisition method, and acquires the second voltage signal according to the first reference voltage to obtain an initial sampling value, and adjusts the first reference voltage according to the initial sampling value, and acquires the second voltage signal according to the adjusted first reference voltage to obtain a target sampling value. Wherein, the signal acquisition circuit includes an acquisition unit, a filtering unit, and a voltage generation unit. The acquisition method of the acquisition unit is adjustable. The acquisition unit is configured to acquire and process the signal to be acquired to obtain a first voltage signal. The filtering unit is connected to the acquisition unit and is configured to filter the first voltage signal to obtain a second voltage signal. The voltage generation unit is configured to output a first reference voltage with adjustable amplitude. Thus, the acquisition method of the acquisition unit can be adjusted, and the control unit controls the acquisition unit according to the type of the signal to be acquired, so that the acquisition unit can acquire different types of signals to be acquired, realizing flexible acquisition of multiple types of signals, thereby improving the acquisition efficiency.

[0088] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a definite sequence list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device), or in combination with these instruction execution systems, apparatus, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by or in combination with an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection portion having one or more wirings (electronic device), a portable computer diskette (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpretation, or other suitable processing as necessary, and then stored in a computer memory.

[0089] It should be understood that various parts of the present invention can be implemented by hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, any one or a combination of the following techniques well known in the art can be used: discrete logic circuits having logic gate circuits for implementing logical functions on data signals, application specific integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), and the like.

[0090] In the description of this specification, the description referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0091] In addition, the terms "first", "second", etc. used in the embodiments of the present invention are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated in this embodiment. Thus, the features defined with terms such as "first" and "second" in the embodiments of the present invention may explicitly or implicitly indicate that at least one such feature is included in this embodiment. In the description of the present invention, the meaning of the word "plurality" is at least two or more than two, such as two, three, four, etc., unless otherwise specifically defined in the embodiments.

[0092] In the present invention, unless otherwise clearly specified or limited in the embodiments, the terms "mounted", "connected", "coupled" and "fixed" etc. appearing in the embodiments shall be understood in a broad sense. For example, the connection can be a fixed connection, a detachable connection, or integrated. Understandably, it can also be a mechanical connection, an electrical connection, etc.; of course, it can also be directly connected, or indirectly connected through an intermediate medium, or it can be the communication inside two components, or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific implementation situations.

[0093] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A signal acquisition circuit, characterized in that: include: A collection unit, wherein the collection mode of the collection unit is adjustable, and the collection unit is configured to collect and process the signal to be collected to obtain a first voltage signal; A filtering unit, the filtering unit is connected to the acquisition unit, and the filtering unit is configured to filter the first voltage signal to obtain a second voltage signal; A voltage generating unit, configured to output a first reference voltage with adjustable amplitude; The control unit is configured to adjust the acquisition method according to the signal type of the signal to be acquired, so that the acquisition unit performs voltage division processing on the signal to be acquired according to the corresponding acquisition method, and acquires the second voltage signal according to the first reference voltage to obtain an initial sampling value, and adjusts the first reference voltage according to the initial sampling value, and acquires the second voltage signal according to the adjusted first reference voltage to obtain a target sampling value.

2. The signal acquisition circuit according to claim 1, characterized in that: The voltage generating unit comprises: a voltage generating module, wherein the input end of the voltage generating module is suitable for connecting to a preset power source, the output end of the voltage generating module is connected to the power input end of the control unit, the enable end of the voltage generating module is connected to the first output end of the control unit, and the voltage generating module is configured to generate a preset voltage according to the preset power source when receiving an enable signal sent by the control unit; A controllable switch module, one end of the controllable switch module is connected to the power input end of the control unit, the other end of the controllable switch module is grounded, the control end of the controllable switch module is connected to the second output end of the control unit, and the controllable switch module is configured to provide zero voltage to the control unit when receiving a first control signal sent by the control unit.

3. The signal acquisition circuit according to claim 2, characterized in that: The control unit includes an analog-to-digital converter, and the control unit is further configured to set the second reference voltage to a first preset voltage so that the analog-to-digital converter generates a first digital signal according to the first preset voltage and the first reference voltage, and determines the initial sampling value according to the first digital signal, and adjusts the first reference voltage or the second reference voltage according to the initial sampling value, so that the analog-to-digital converter generates a second digital signal according to the adjusted first reference voltage or the adjusted second reference voltage, and determines the target sampling value according to the second digital signal.

4. The signal acquisition circuit according to claim 3, characterized in that: The control unit is further configured to output the first control signal and stop outputting the enable signal before setting the second reference voltage to the first preset voltage, so that the analog-to-digital converter generates the first digital signal according to the first preset voltage and the zero voltage.

5. The signal acquisition circuit according to claim 4, characterized in that: The control unit is also configured to stop outputting the first control signal and output the enable signal when the initial sampling value is greater than a second preset voltage, so that the analog-to-digital converter generates the second digital signal based on the first preset voltage and the preset voltage, wherein the second preset voltage is less than the first preset voltage.

6. The signal acquisition circuit according to claim 5, characterized in that: The target sampling value is calculated according to the following formula: V=(ADC / 2^n)*(Vref1-Vref)+Vref Wherein, ADC is the second digital signal, n is the number of bits of the analog-to-digital converter, Vref1 is the first preset voltage, and Vref is the preset voltage.

7. The signal acquisition circuit according to claim 5, characterized in that: The control unit is further configured to, when the initial sampling value is less than or equal to the second preset voltage, set the second reference voltage to the second preset voltage so that the analog-to-digital converter generates the second digital signal according to the second preset voltage and the zero voltage.

8. The signal acquisition circuit according to claim 7, characterized in that: The target sampling value is calculated according to the following formula: V=(ADC / 2^n)*Vref2 Wherein, ADC is the second digital signal, n is the number of bits of the analog-to-digital converter, and Vref2 is the second preset voltage.

9. The signal acquisition circuit according to claim 2, characterized in that: The controllable switch module comprises: a first resistor, one end of the first resistor being connected to the second output end of the control unit, and the other end of the first resistor being grounded; A first switch tube, wherein a first end of the first switch tube is connected to a power input end of the control unit, a second end of the first switch tube is grounded, and a control end of the first switch tube is connected to one end of the first resistor.

10. The signal acquisition circuit according to claim 1, characterized in that: The acquisition unit comprises: A second resistor, one end of which is suitable for inputting the signal to be collected; a second switch tube, wherein a first end of the second switch tube is connected to the other end of the second resistor, a second end of the second switch tube is grounded, and a control end of the second switch tube is connected to a third output end of the control unit; a third resistor, one end of the third resistor being connected to one end of the second resistor; a fourth resistor, one end of the fourth resistor being connected to the other end of the third resistor and having a first node, and the other end of the fourth resistor being grounded; a fifth resistor, one end of which is connected to the first node; A third switch tube, wherein a first end of the third switch tube is connected to the other end of the fifth resistor, a second end of the third switch tube is grounded, and a control end of the third switch tube is connected to the fourth output end of the control unit.

11. The signal acquisition circuit according to claim 10, characterized in that: The control unit is further configured to: When the signal to be collected is a voltage signal and the amplitude of the signal to be collected is within a first preset range, controlling the second switch tube and the third switch tube to be turned off respectively; or When the signal to be collected is a voltage signal and the amplitude of the signal to be collected is within a second preset range, the second switch tube is controlled to be turned off, and the third switch tube is controlled to be turned on, wherein the maximum value of the second preset range is greater than the maximum value of the first preset range; or When the signal to be collected is a current signal and the amplitude of the signal to be collected is within a third preset range, the second switch tube is controlled to be turned on, and the third switch tube is controlled to be turned off.

12. The signal acquisition circuit according to any one of claims 1 to 11, characterized in that: The filtering unit comprises: a first filtering module, the first filtering module being connected to the acquisition unit, and the first filtering module being configured to perform high-frequency filtering on the first voltage signal and to perform lead compensation on the first voltage signal to obtain the second voltage signal; A second filtering module, wherein the second filtering module is connected to the first filtering module, and the second filtering module is configured to perform common-mode interference suppression on the first voltage signal together with the first filtering module.

13. The signal acquisition circuit according to claim 12, characterized in that: The first filtering module comprises: An operational amplifier, wherein the positive input terminal of the operational amplifier is connected to the output terminal of the acquisition unit, and the output terminal of the operational amplifier is connected to the input terminal of the control unit; a sixth resistor, one end of the sixth resistor being connected to the negative input terminal of the operational amplifier and having a second node, and the other end of the sixth resistor being connected to the output terminal of the operational amplifier; a seventh resistor, one end of the seventh resistor being connected to the second node, and the other end of the seventh resistor being grounded; A first capacitor is connected in parallel with the sixth resistor.

14. The signal acquisition circuit according to claim 13, characterized in that: The second filtering module includes: a second capacitor, and the second capacitor is arranged between the positive input terminal of the operational amplifier and the negative input terminal of the operational amplifier.

15. The signal acquisition circuit according to claim 1, characterized in that: Also includes: A protection unit, wherein the input end of the protection unit is suitable for inputting the signal to be collected, the output end of the protection unit is connected to the collection unit, and the protection unit is configured to perform overcurrent protection and overvoltage protection on the collection unit.

16. The signal acquisition circuit according to claim 15, characterized in that: The protection unit comprises: A thermistor, one end of which is suitable for connecting to the positive electrode of the signal to be collected; a first diode, one end of which is connected to the other end of the thermistor, and the other end of which is grounded and suitable for connecting to the cathode of the signal to be collected; A third capacitor is connected in parallel with the first diode.

17. A signal acquisition method, characterized in that: Applied to a signal acquisition circuit, the signal acquisition circuit includes an acquisition unit, a filtering unit and a voltage generating unit, the voltage division mode of the acquisition unit is adjustable, the acquisition unit is configured to perform voltage division processing on the signal to be acquired to obtain a first voltage signal, the filtering unit is connected to the acquisition unit, the filtering unit is configured to perform filtering processing on the first voltage signal to obtain a second voltage signal, and the voltage generating unit is configured to output a first reference voltage with adjustable amplitude, the method includes: The voltage division mode is adjusted according to the signal type of the signal to be collected, so that the collection unit performs voltage division processing on the signal to be collected according to the corresponding voltage division mode; Sampling the second voltage signal according to the reference voltage to obtain an initial sampling value; The first reference voltage is adjusted according to the initial sampling value, and the second voltage signal is collected according to the adjusted first reference voltage to obtain a target sampling value.

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