Sampling circuit

Abstract

The utility model discloses a sampling circuit. The sampling circuit comprises an input module, a switch module, a channel selection module and a processor. The input module is connected with the switch module, and the input module is configured to convert the plurality of sampling signals into a plurality of voltage signals; the channel selection module is connected with the switch module; the switch module is connected with the processor; the switch module comprises a plurality of transmission channels, and the number of the transmission channels is greater than or equal to that of the voltage signals; the channel selection module is configured to sequentially gate a plurality of transmission channels of the switch module, so that the switch module sequentially transmits a plurality of voltage signals to the processor, and the processor is configured to convert the voltage signals into digital signals. According to the technical scheme of the utility model, the cost can be reduced, and transmission channel resources are sufficient.

Description

Technical Field

[0001] The utility model relates to the technical field of sampling, in particular to a sampling circuit. Background Art

[0002] In many scenarios, it is necessary to set up sensors to collect parameter information, such as temperature sensors to collect temperature information, DC parameter information, oil pressure and oil level information, etc. The parameter information collected by the sensor can be converted into current output. Therefore, it is necessary to collect current information through measuring equipment to obtain parameter information.

[0003] Current measurement equipment generally converts current values ​​into voltage values ​​through current conversion circuits, and then transmits the voltage values ​​to analog-to-digital conversion circuits through follower circuits, which convert the voltage values ​​into digital quantities. This method is costly and has the problem of insufficient number of channels for highly integrated devices. Utility Model Content

[0004] The utility model provides a sampling circuit to solve the problem that the cost of measuring equipment is high and the number of channels is insufficient for high-integration equipment.

[0005] The utility model provides a sampling circuit, which includes: an input module, a switch module, a channel selection module and a processor;

[0006] The input module is connected to the switch module, and the input module is configured to convert a plurality of sampling signals into a plurality of voltage signals;

[0007] The channel selection module is connected to the switch module, and the switch module is connected to the processor; the switch module includes multiple transmission channels, and the number of the transmission channels is greater than or equal to the number of the voltage signals; the channel selection module is configured to sequentially select the multiple transmission channels of the switch module so that the switch module transmits the multiple voltage signals to the processor in sequence, and the processor is configured to convert the voltage signals into digital signals.

[0008] Optionally, the sampling circuit further includes a voltage reference module;

[0009] The voltage reference module is connected to the switch module, and the switch module is configured to transmit the reference voltage output by the voltage reference module to the processor when the channel selection module selects the transmission channel corresponding to the voltage reference module; the processor is configured to calculate the difference between the received reference voltage and the voltage signal, convert the difference into the original value corresponding to the voltage signal, and convert the original value into the digital signal.

[0010] Optionally, the voltage reference module includes a first resistor, a second resistor, a third resistor and a voltage stabilizing diode;

[0011] The first end of the first resistor is connected to the first power supply, the second end of the first resistor is connected to the first end of the second resistor, the second end of the second resistor is connected to the first end of the third resistor, and the second end of the third resistor is grounded; the second end of the second resistor is also connected to the switch module;

[0012] The first end of the voltage-stabilizing diode is connected to the second end of the first resistor, the second end of the voltage-stabilizing diode is connected to the second end of the first resistor, and the third end of the voltage-stabilizing diode is grounded.

[0013] Optionally, the switch module includes a plurality of first switches and a second switch;

[0014] A first end of the first switch is connected to the input module, and a second end of the first switch is connected to the processor;

[0015] The first end of the second switch is connected to the voltage reference module, and the second end of the second switch is connected to the processor; the channel selection module is configured to control a plurality of the first switches and the second switches to be turned on in sequence.

[0016] Optionally, the channel selection module includes a timer and at least one optocoupler isolation unit;

[0017] The first end of the optocoupler isolation unit is connected to the second power supply, the second end of the optocoupler isolation unit is connected to the timer, the third end of the optocoupler isolation unit is connected to the channel selection end of the switch module, and the fourth end of the optocoupler isolation unit is connected to the first power supply; the timer is configured to output at least one square wave signal to the switch module through the optocoupler isolation unit so that the transmission channel of the switch module is turned on in sequence; wherein, when the timer outputs at least two square wave signals, the widths of different square wave signals are different.

[0018] Optionally, the sampling circuit further includes an isolation module;

[0019] The isolation module is connected between the switch module and the processor; the isolation module is configured to transmit the voltage signal transmitted by the switch module to the processor.

[0020] Optionally, the isolation module includes an isolation unit and a differential unit;

[0021] The input end of the isolation unit is connected to the switch module, and the isolation unit is configured to output a first sub-voltage signal and a second sub-voltage signal after differentiating the voltage signal;

[0022] The input end of the differential unit is respectively connected to the first output end and the second output end of the isolation unit, and the output end of the differential unit is connected to the processor. The differential unit is configured to output the difference between the first sub-voltage signal and the second sub-voltage signal to the processor so as to transmit the processed voltage signal to the processor.

[0023] Optionally, the isolation unit includes an isolation amplifier, a fourth resistor, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor and a fifth capacitor;

[0024] The fourth resistor is connected between the switch module and the input end of the isolation amplifier; the first output end of the isolation amplifier is connected to the first input end of the differential unit, and the second output end of the isolation amplifier is connected to the second input end of the differential unit;

[0025] The input terminal of the isolation amplifier is also grounded through the first capacitor;

[0026] The first power supply terminal of the isolation amplifier is connected to the first power supply, the first power supply terminal of the isolation amplifier is also grounded through the second capacitor, and the third capacitor is connected in parallel with the second capacitor;

[0027] The second power supply terminal of the isolation amplifier is connected to the third power supply, the second power supply terminal of the isolation amplifier is also grounded through the fourth capacitor, and the fifth capacitor is connected in parallel with the fourth capacitor.

[0028] Optionally, the differential unit includes a differential amplifier, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor and a sixth capacitor;

[0029] The first input end of the differential amplifier is connected to the first output end of the isolation unit through the fifth resistor, the second input end of the differential amplifier is connected to the second output end of the isolation unit through the sixth resistor, and the output end of the differential amplifier is connected to the processor;

[0030] The first input terminal of the differential amplifier is also grounded through the seventh resistor, and the first input terminal of the differential amplifier is also grounded through the sixth capacitor;

[0031] The eighth resistor is connected between the output terminal of the differential amplifier and the second input terminal of the differential amplifier.

[0032] Optionally, the input module includes a plurality of ninth resistors;

[0033] The first end of the ninth resistor is connected to the sampling signal, the second end of the ninth resistor is grounded, and the first end of the ninth resistor is also connected to the switch module.

[0034] The technical solution of the embodiment of the utility model, the sampling circuit includes: an input module, a switch module, a channel selection module and a processor, the channel selection module can output different selection signals to the switch module at a fixed time, can sequentially conduct different transmission channels, so that multiple transmission channels of the switch module can be sequentially selected to realize automatic switching of channels. In this way, the sampling circuit can transmit multi-channel voltage signals and realize the collection of multiple sampling signals. And through the switch module and the channel selection module, the collection of multiple voltage signals can be realized, which can reduce costs, and the transmission channel resources are sufficient.

[0035] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present utility model, nor are they intended to limit the scope of the present utility model. Other features of the present utility model will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0037] Figure 1 It is a structural schematic diagram of a sampling circuit provided by an embodiment of the utility model;

[0038] Figure 2 It is a structural schematic diagram of another sampling circuit provided by an embodiment of the utility model;

[0039] Figure 3 It is a structural schematic diagram of another sampling circuit provided by an embodiment of the utility model;

[0040] Figure 4 This is a schematic diagram of a timer output waveform provided by an embodiment of the utility model;

[0041] Figure 5 This is a structural diagram of another sampling circuit provided by an embodiment of the utility model. DETAILED DESCRIPTION

[0042] In order to enable those skilled in the art to better understand the solution of the utility model, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is only a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the utility model.

[0043] It should be noted that the terms "first", "second", etc. in the specification and claims of the utility model and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the utility model described here can be implemented in an order other than those illustrated or described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0044] The embodiment of the present application provides a sampling circuit, Figure 1 is a schematic diagram of a sampling circuit provided by an embodiment of the utility model, referring to Figure 1 , the sampling circuit includes: an input module 110, a switch module 120, a channel selection module 130 and a processor 140;

[0045] The input module 110 is connected to the switch module 120 , and the input module 110 is configured to convert a plurality of sampling signals V0 into a plurality of voltage signals;

[0046] The channel selection module 130 is connected to the switch module 120, and the switch module 120 is connected to the processor 140; the switch module 120 includes multiple transmission channels, and the number of transmission channels is greater than or equal to the number of voltage signals; the channel selection module 130 is configured to sequentially select the multiple transmission channels of the switch module 120 so that the switch module 120 transmits the multiple voltage signals to the processor 140 in sequence, and the processor 140 is configured to convert the voltage signals into digital signals.

[0047] Among them, after the sensor and other equipment collect parameter information, it is converted into a sampling signal V0 for output, and the sampling signal V0 is, for example, a current signal. The input module 110 can collect the sampling signal V0 and convert the sampling signal V0 into a voltage signal. The input module 110 may include multiple input terminals and multiple output terminals, which are convenient for inputting multiple sampling signals and outputting multiple voltage signals. The switch module 120 includes multiple transmission channels, and the channel selection module 130 can select the channels in the switch module 120, so that the voltage signal is transmitted to the processor 140 through the transmission channel in the switch module 120. The switch module 120 may include multiple input terminals, and multiple voltage signals may be input. The switch module 120 may include an output terminal to output multiple voltage signals in sequence.

[0048] The processor 140 may include an analog-to-digital conversion unit, which may be implemented by an analog-to-digital conversion chip. The processor 140 may be a single-chip microcomputer or other device, which is not limited in this embodiment. The processor 140 converts the voltage signal into a digital signal to facilitate subsequent transmission, display or processing of the digital signal, thereby intuitively displaying the collected value.

[0049] For example, the channel selection module 130 may select one transmission channel in the switch module 120 at a time, so that the corresponding voltage signal is transmitted to the processor 140 through the conductive transmission channel, and then select the next transmission channel in the switch module 120, so that the corresponding voltage signal is transmitted to the processor 140 through the conductive transmission channel, and repeat this process, sequentially select multiple transmission channels of the switch module 120, so that the switch module 120 sequentially transmits multiple voltage signals to the processor 140. The order in which the channel selection module 130 selects the transmission channels may be selected one by one, or every other channel, or in other ways, which is not limited in this embodiment.

[0050] Specifically, the channel selection module 130 can be implemented by a timer or a processor, and different transmission channels can be turned on in sequence by timing output of different selection signals to the switch module 120, so that multiple transmission channels of the switch module 120 can be selected in sequence to achieve automatic switching of channels. In this way, the sampling circuit can transmit multiple voltage signals and realize the collection of multiple sampling signals V0. And through the switch module 120 and the channel selection module 130, the collection of multiple voltage signals can be realized, which can reduce costs, and the transmission channel resources are sufficient.

[0051] The technical solution of this embodiment is that the sampling circuit includes: an input module, a switch module, a channel selection module and a processor. The channel selection module can output different selection signals to the switch module at a fixed time, and can sequentially conduct different transmission channels, so that multiple transmission channels of the switch module can be sequentially selected to realize automatic switching of channels. In this way, the sampling circuit can transmit multi-channel voltage signals and realize the collection of multiple sampling signals. And through the switch module and the channel selection module, the collection of multiple voltage signals can be realized, which can reduce costs, and the transmission channel resources are sufficient.

[0052] Based on the above technical solutions, Figure 2 is a schematic diagram of another sampling circuit provided by an embodiment of the utility model. Figure 2 , the sampling circuit also includes a voltage reference module 150;

[0053] The voltage reference module 150 is connected to the switch module 120, and the switch module 120 is configured to transmit the reference voltage output by the voltage reference module 150 to the processor 140 when the channel selection module 130 selects the transmission channel corresponding to the voltage reference module 150; the processor 140 is configured to calculate the difference between the received reference voltage and the voltage signal, and convert the difference into the original value corresponding to the voltage signal, and convert the original value into a digital signal.

[0054] The processor 140 may include a differential device, which calculates the difference between the received reference voltage and the voltage signal. The processor 140 may also include an operational amplifier device, which adds the difference to the voltage value corresponding to the reference voltage, or multiplies the difference by a preset coefficient to obtain the original value corresponding to the voltage signal. The processor 140 may also be a single-chip microcomputer or other device, which is not limited in this embodiment.

[0055] Specifically, by using the switch module 120 to transmit the reference voltage to the processor 140, the processor 140 calculates the difference between the reference voltage and the voltage signal, and common mode interference can be eliminated. Then the processor 140 adds the difference to the voltage value corresponding to the reference voltage, or multiplies the difference by a preset coefficient to obtain the original value corresponding to the voltage signal, that is, to obtain the voltage value corresponding to the voltage signal output by the input module 110, that is, to obtain the voltage value after eliminating the interference signal, so that the voltage value finally obtained by the processor 140 is closer to the value corresponding to the voltage signal output by the input module 110, which can improve the accuracy of signal transmission and improve the anti-interference ability of the sampling circuit. The processor 140 converts the original value into a digital signal, that is, obtains a digital signal of the voltage value corresponding to the sampling information, which is convenient for subsequent transmission, display or processing of digital signals, thereby intuitively displaying the collected values.

[0056] In addition, after obtaining the value corresponding to the voltage signal, the processor 140 can multiply it by the sampling coefficient, which is the proportional relationship between the voltage value of the voltage signal output by the input module 110 and the sampling value corresponding to the sampling signal, so as to obtain the sampling value, and then convert the sampling value into a digital signal, and then transmit and display the digital signal corresponding to the sampling value, so as to display the value corresponding to the sampling signal.

[0057] Based on the above technical solutions, Figure 3 is a schematic diagram of a structure of another sampling circuit provided by an embodiment of the utility model. Figure 3 , the voltage reference module 150 includes a first resistor R1, a second resistor R2, a third resistor R3 and a voltage stabilizing diode D1;

[0058] A first end of the first resistor R1 is connected to the first power source V1, a second end of the first resistor R1 is connected to a first end of the second resistor R2, a second end of the second resistor R2 is connected to a first end of the third resistor R3, and a second end of the third resistor R3 is grounded; a second end of the second resistor R2 is also connected to the switch module 120;

[0059] A first end of the Zener diode D1 is connected to the second end of the first resistor R1 , a second end of the Zener diode D1 is connected to the second end of the first resistor R1 , and a third end of the Zener diode D1 is grounded.

[0060] The voltage corresponding to the first power source V1 is, for example, 5V, or other voltage values, which can be specifically determined according to the required reference voltage value, and is not limited in this embodiment.

[0061] Specifically, the first resistor R1 has a current limiting function. The reference voltage is obtained by voltage division of the second resistor R2 and the third resistor R3, and the value of the reference voltage can be adjusted by adjusting the resistance values ​​of the second resistor R2 and the third resistor R3 to meet different sampling requirements. The voltage stabilizing diode D1 has a voltage stabilizing function, stabilizing the voltage between the second end of the first resistor R1 and the ground, so that the voltage reference module 150 outputs a stable reference voltage.

[0062] Optionally, refer to Figure 3 , the switch module 120 includes a plurality of first switches 121 and a second switch 122;

[0063] A first end of the first switch 121 is connected to the input module 110 , and a second end of the first switch 121 is connected to the processor 140 ;

[0064] The first end of the second switch 122 is connected to the voltage reference module 150 , and the second end of the second switch 122 is connected to the processor 140 ; ​​the channel selection module 130 is configured to control the plurality of first switches 121 and second switches 122 to be turned on in sequence.

[0065] Specifically, each first switch 121 corresponds to a transmission channel, and each second switch 122 corresponds to a transmission channel. By sending a selection signal to the switch module 120 through the channel selection module 130, one of the multiple first switches 121 and one second switch 122 in the switch module 120 can be turned on, thereby transmitting a voltage signal or a reference voltage.

[0066] Exemplarily, for example, the switch module 120 includes seven first switches 121 and one second switch 122, that is, there are eight switches in total. When the selection signal sent by the channel selection module 130 to the switch module 120 is 100, the first first switch 121 is turned on. When the selection signal sent by the channel selection module 130 to the switch module 120 is 010, the second first switch 121 is turned on. When the selection signal sent by the channel selection module 130 to the switch module 120 is 111, the second switch 122 is turned on. In this way, by sending different selection signals to the switch module 120, different switches can be controlled to be turned on, that is, different transmission channels can be controlled to be turned on, so as to sequentially transmit multiple voltage signals and reference voltages.

[0067] Optionally, refer to Figure 3 The channel selection module 130 includes a timer 131 and at least one optocoupler isolation unit 132; a first end of the optocoupler isolation unit 132 is connected to the second power supply V2, a second end of the optocoupler isolation unit 132 is connected to the timer 131, a third end of the optocoupler isolation unit 132 is connected to the channel selection end of the switch module 120, and a fourth end of the optocoupler isolation unit 132 is connected to the first power supply V1; the timer 131 is configured to output at least one square wave signal to the switch module 120 through the optocoupler isolation unit 132, so that the transmission channels of the switch module 120 are turned on in sequence; wherein, when the timer 131 outputs at least two square wave signals, the widths of different square wave signals are different.

[0068] The power supply voltage provided by the second power supply V2 is, for example, 3.3V, or may be a power supply voltage of other values, such as 2.5V, etc., which is not limited in this embodiment.

[0069] Specifically, the square wave signal includes a low level and a high level, and the width of the square wave signal is, for example, the duration of the square wave signal being at a high level. When the timer 131 starts timing, for example, a low level is output by default, and when the timing reaches a preset duration, a high level is output. In this way, the timer 131 can output a selection signal of different signals to the switch module 120 through the optical coupling isolation unit 131, so that different first switches 121 or second switches 122 in the switch module 120 are turned on, thereby turning on the transmission channel of the corresponding switch module 120.

[0070] When the switch module 120 includes a first switch 121 and a second switch 122, an output terminal of the timer 131 is connected to the channel selection terminal of the switch module 120 through an optocoupler isolation unit 132. For example, when the timer 131 outputs a low level, the first switch 121 is turned on, and after the timer 131 counts for a period of time, it outputs a high level, and the second switch 122 is turned on.

[0071] When the switch module 120 includes three first switches 121 and one second switch 122, the two output ends of the timer 131 are respectively connected to the channel selection end of the switch module 120 through two optical coupling isolation units 132. By timing the output of different square wave signals to the switch module 120, different square wave signals can form different selection signals, so that the switch module 120 controls the first switch 121 or the second switch 122 to be turned on according to different selection signals.

[0072] Exemplarily, the switch module 120 includes, for example, 7 first switches 121 (the 7 first switches 121 are numbered from 0 to 6) and 1 second switch 122 (the second switch 122 is numbered 7), and the three output ends of the timer 131 are connected to the channel selection end of the switch module 120 through three optical coupling isolation units 132. The period of the square wave signal output by the first output end of the timer 131 is, for example, 2a, the period of the square wave signal output by the second output end of the timer 131 is, for example, 4a, and the period of the square wave signal output by the third output end of the timer 131 is, for example, 8a. Wherein, a is, for example, 5 microseconds, 10 microseconds, or 1 microsecond, which is not limited in this embodiment.

[0073] For example, Figure 4 Schematic diagram of a timer output waveform provided by an embodiment of the utility model, such as Figure 4As shown, the square wave signals outputted by the three output terminals of the timer 131 are respectively the first square wave signal S1, the second square wave signal S2 and the third square wave signal S3. When the timer 131 is turned on, the three output terminals of the timer 131 all output low levels, and the signal received by the channel selection terminal of the switch module 120 is "000", and the switch module 120 controls the 0th first switch 121 to be turned on, and the 0th first switch 121 transmits a voltage signal to the processor 140. When the timer 131 reaches a, the first output terminal of the timer 131 outputs a high level, and the second and third output terminals of the timer 131 output low levels, and the signal received by the channel selection terminal of the switch module 120 is "100", and the switch module 120 controls the 1st first switch 121 to be turned on, and the 1st first switch 121 transmits a voltage signal to the processor 140. When the timer 131 reaches 2a, the second output terminal of the timer 131 outputs a high level, and the first output terminal and the third output terminal of the timer 131 output a low level, then the signal received by the channel selection terminal of the switch module 120 is "010", and the switch module 120 controls the second first switch 121 to be turned on, and the second first switch 121 transmits a voltage signal to the processor 140. When the timer 131 reaches 3a, the first output terminal and the second output terminal of the timer 131 both output a high level, and the third output terminal of the timer 131 outputs a low level, then the signal received by the channel selection terminal of the switch module 120 is "110", and the switch module 120 controls the third first switch 121 to be turned on, and the third first switch 121 transmits a voltage signal to the processor 140. When the timer 131 reaches 4a, the third output terminal of the timer 131 outputs a high level, and the first output terminal and the second output terminal of the timer 131 both output a low level, then the signal received by the channel selection terminal of the switch module 120 is "001", and the switch module 120 controls the fourth first switch 121 to be turned on, and the fourth first switch 121 transmits a voltage signal to the processor 140. When the timer 131 reaches 5a, the first output terminal and the third output terminal of the timer 131 output a high level, and the second output terminal of the timer 131 outputs a low level, then the signal received by the channel selection terminal of the switch module 120 is "101", and the switch module 120 controls the fifth first switch 121 to be turned on, and the fifth first switch 121 transmits a voltage signal to the processor 140. When the timer 131 reaches 6a, the second output terminal and the third output terminal of the timer 131 output a high level, and the first output terminal of the timer 131 outputs a low level, then the signal received by the channel selection terminal of the switch module 120 is "011", and the switch module 120 controls the sixth first switch 121 to turn on, then the sixth first switch 121 transmits a voltage signal to the processor 140.When the timer 131 reaches 7a, the third output terminal of the timer 131 outputs a high level, and the signal received by the channel selection terminal of the switch module 120 is "111". The switch module 120 controls the second switch 122 to be turned on, and the second switch 122 transmits the reference voltage to the processor 140. When the timer 131 reaches 8a, the transmission of the next cycle begins. In this way, the multiple first switches 121 and the second switches 122 of the switch module 120 are turned on in sequence, and the channels are automatically switched, thereby realizing multi-channel transmission.

[0074] Among them, the start of timer 131 can be controlled by processor 140, or by turning on a switch. For example, a switch is connected to the power supply end of timer 131, and the switch is pressed, and timer 131 is powered on and starts timing. Timer 131 can also be turned on by other methods, which is not limited in this embodiment.

[0075] On the basis of the above technical solutions, Figure 5 is a schematic diagram of a structure of another sampling circuit provided by an embodiment of the utility model. Figure 5 , the sampling circuit further includes an isolation module 160;

[0076] The isolation module 160 is connected between the switch module 120 and the processor 140 ; ​​the isolation module 160 is configured to transmit the voltage signal transmitted by the switch module 120 to the processor 140 .

[0077] Specifically, by setting up the isolation module 160, the analog signal and the digital signal are isolated, which can avoid mutual interference between the analog signal and the digital signal, which is conducive to further improving the anti-interference ability and stability of the sampling circuit, improving the stability of the subsequent circuit, and improving the accuracy of sampling. In addition, the switch module 120 has only one output terminal, so only one isolation module 160 is needed to realize signal transmission, which is conducive to further reducing costs.

[0078] Optionally, refer to Figure 5 , the isolation module 160 includes an isolation unit 161 and a differential unit 162;

[0079] The input end of the isolation unit 161 is connected to the switch module 120, and the isolation unit 161 is configured to output a first sub-voltage signal and a second sub-voltage signal after differentiating the voltage signal;

[0080] The input end of the differential unit 162 is respectively connected to the first output end and the second output end of the isolation unit 161, and the output end of the differential unit 162 is connected to the processor 140. The differential unit 162 is configured to output the difference between the first sub-voltage signal and the second sub-voltage signal to the processor 140 so as to transmit the processed voltage signal to the processor 140.

[0081] Specifically, the isolation unit 161 outputs a first sub-voltage signal and a second sub-voltage signal after differentiating the voltage signal, that is, the difference between the first sub-voltage signal and the second sub-voltage signal is a voltage signal, so that the differential unit 162 calculates the first sub-voltage signal and the second sub-voltage signal to obtain a voltage signal, and common-mode interference can be eliminated, thereby transmitting a more accurate voltage signal to the processor 140, which is beneficial to improving the accuracy of signal transmission.

[0082] Optionally, refer to Figure 5 , the isolation unit 161 includes an isolation amplifier U1, a fourth resistor R4, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4 and a fifth capacitor C5;

[0083] The fourth resistor R4 is connected between the switch module 120 and the input terminal of the isolation amplifier U1; the first output terminal of the isolation amplifier U1 is connected to the first input terminal of the differential unit 162, and the second output terminal of the isolation amplifier U1 is connected to the second input terminal of the differential unit 162;

[0084] The input terminal of the isolation amplifier U1 is also grounded via the first capacitor C1;

[0085] The first power supply terminal of the isolation amplifier U1 is connected to the first power supply V1, the first power supply terminal of the isolation amplifier U1 is also grounded through the second capacitor C2, and the third capacitor C3 is connected in parallel with the second capacitor C2;

[0086] The second power supply terminal of the isolation amplifier U1 is connected to the third power supply V3. The second power supply terminal of the isolation amplifier U1 is also grounded through the fourth capacitor C4. The fifth capacitor C5 is connected in parallel with the fourth capacitor C4.

[0087] Specifically, by setting the fourth resistor R4 and the first capacitor C1, the voltage signal input to the isolation amplifier U1 can be filtered, thereby eliminating clutter and further improving the accuracy and reliability of signal transmission. The power supply voltage provided by the first power supply V1 is, for example, 5V, and the first power supply V1 is, for example, a standard power supply. The power supply voltage provided by the third power supply V3 is, for example, 5V, and the third power supply V3 is, for example, an analog power supply. By setting the second capacitor C2 and the third capacitor C3, the power supply voltage provided by the first power supply V1 can be filtered; by setting the fourth capacitor C4 and the fifth capacitor C5, the power supply voltage provided by the third power supply V1 can be filtered, thereby improving the reliability of power supply.

[0088] In addition, the first ground terminal of the isolation amplifier U1 is grounded, and the second ground terminal of the isolation amplifier U1 is grounded. For example, the first ground terminal of the isolation amplifier U1 is connected to the standard ground, and the second ground terminal of the isolation amplifier U1 is connected to the analog ground.

[0089] Optionally, refer to Figure 5 , the differential unit 162 includes a differential amplifier U2, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8 and a sixth capacitor C6;

[0090] The first input terminal of the differential amplifier U2 is connected to the first output terminal of the isolation unit 161 through the fifth resistor R5, the second input terminal of the differential amplifier U2 is connected to the second output terminal of the isolation unit 161 through the sixth resistor R6, and the output terminal of the differential amplifier U2 is connected to the processor 140;

[0091] The first input terminal of the differential amplifier U2 is also grounded through a seventh resistor R7, and the first input terminal of the differential amplifier U2 is also grounded through a sixth capacitor C6;

[0092] The eighth resistor R8 is connected between the output terminal of the differential amplifier U2 and the second input terminal of the differential amplifier U2.

[0093] Specifically, the differential amplifier U2 can amplify the difference between the input first sub-voltage signal and the second sub-voltage signal and output it. The amplification factor is the gain of the differential amplifier U2. The gain of the differential amplifier U2 is related to the feedback resistor (the eighth resistor R8), the input resistor (the fifth resistor R5 and the sixth resistor R6) and the output resistor. Therefore, by adjusting the resistance values ​​of the fifth resistor R5, the sixth resistor R6 and the eighth resistor R8, the amplification factor of the differential amplifier U2 can be limited, so as to facilitate the restoration of the voltage signal output by the switch module 120.

[0094] Optionally, refer to Figure 5 , the input module 110 includes a plurality of ninth resistors R9;

[0095] A first end of the ninth resistor R9 is connected to the sampling signal, a second end of the ninth resistor R9 is grounded, and a first end of the ninth resistor R9 is also connected to the switch module 120 .

[0096] Specifically, the ninth resistor R9 can convert the current value corresponding to the sampling signal into a voltage value, thereby transmitting the voltage signal to the switch module 120. By setting a plurality of ninth resistors R9, a plurality of sampling signals can be converted simultaneously, and each ninth resistor R9 can correspond to a transmission channel of the switch module 120, thereby facilitating multi-channel transmission. Moreover, the cost of the ninth resistor R9 is low, and the volume of the ninth resistor R9 is small. When the integration is high, a plurality of ninth resistors R9 can be set to realize multi-channel transmission, thereby ensuring the number of transmission channels.

[0097] Optionally, refer to Figure 5The optocoupler isolation unit 132 includes an optocoupler isolator U3, a tenth resistor R10 and an eleventh resistor R11, the tenth resistor R10 is connected between the first end of the optocoupler isolator U3 and the second power supply V2, the second end of the optocoupler isolation unit 132 is connected to the timer 131, the third end of the optocoupler isolation unit 132 is connected to the channel selection end of the switch module 120, and the eleventh resistor R11 is connected between the fourth end of the optocoupler isolation unit 132 and the first power supply V1. In this way, when the timer 131 outputs a low level, the third end of the optocoupler isolator U3 is a low level, and when the timer 131 outputs a high level, the third end of the optocoupler isolator U3 is a high level, thereby realizing signal transmission and isolation.

[0098] The technical solution of this embodiment, by setting multiple ninth resistors R9 as input modules 110, can simultaneously convert the current values ​​corresponding to multiple sampling signals into voltage values, thereby transmitting multiple voltage signals to the switch module 120. By outputting a square wave signal to the switch module 120 through the timer 131, multiple first switches 121 and second switches 122 can be sequentially selected, so that the transmission channels of the switch module 120 are sequentially turned on, thereby sequentially transmitting multiple voltage signals and reference voltages, and realizing multi-channel transmission. In addition, by setting an isolation module 160, signal isolation and transmission can be realized, and the isolation module 160 includes an isolation amplifier U1 and a differential amplifier U2. After differential calculation, common-mode interference can be eliminated, and the accuracy and reliability of signal transmission can be improved.

[0099] The above specific implementations do not constitute a limitation on the protection scope of the present utility model. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present utility model shall be included in the protection scope of the present utility model.

Claims

1. A sampling circuit, characterized in that: include: Input module, switch module, channel selection module and processor; The input module is connected to the switch module, and the input module is configured to convert a plurality of sampling signals into a plurality of voltage signals; The channel selection module is connected to the switch module, and the switch module is connected to the processor; the switch module includes multiple transmission channels, and the number of the transmission channels is greater than or equal to the number of the voltage signals; the channel selection module is configured to sequentially select the multiple transmission channels of the switch module so that the switch module transmits the multiple voltage signals to the processor in sequence, and the processor is configured to convert the voltage signals into digital signals.

2. The sampling circuit according to claim 1, characterized in that: The sampling circuit also includes a voltage reference module; The voltage reference module is connected to the switch module, and the switch module is configured to transmit the reference voltage output by the voltage reference module to the processor when the channel selection module selects the transmission channel corresponding to the voltage reference module; The processor is configured to calculate a difference between the received reference voltage and the voltage signal, convert the difference into an original value corresponding to the voltage signal, and convert the original value into the digital signal.

3. The sampling circuit according to claim 2, characterized in that: The voltage reference module includes a first resistor, a second resistor, a third resistor and a voltage stabilizing diode; The first end of the first resistor is connected to the first power supply, the second end of the first resistor is connected to the first end of the second resistor, the second end of the second resistor is connected to the first end of the third resistor, and the second end of the third resistor is grounded; the second end of the second resistor is also connected to the switch module; The first end of the voltage-stabilizing diode is connected to the second end of the first resistor, the second end of the voltage-stabilizing diode is connected to the second end of the first resistor, and the third end of the voltage-stabilizing diode is grounded.

4. The sampling circuit according to claim 2, characterized in that: The switch module includes a plurality of first switches and a second switch; A first end of the first switch is connected to the input module, and a second end of the first switch is connected to the processor; The first end of the second switch is connected to the voltage reference module, and the second end of the second switch is connected to the processor; the channel selection module is configured to control a plurality of the first switches and the second switches to be turned on in sequence.

5. The sampling circuit according to claim 1, characterized in that: The channel selection module includes a timer and at least one optocoupler isolation unit; The first end of the optocoupler isolation unit is connected to the second power supply, the second end of the optocoupler isolation unit is connected to the timer, the third end of the optocoupler isolation unit is connected to the channel selection end of the switch module, and the fourth end of the optocoupler isolation unit is connected to the first power supply; the timer is configured to output at least one square wave signal to the switch module through the optocoupler isolation unit so that the transmission channels of the switch module are turned on in sequence; wherein, when the timer outputs at least two square wave signals, the widths of different square wave signals are different.

6. The sampling circuit according to claim 1, characterized in that: The sampling circuit also includes an isolation module; The isolation module is connected between the switch module and the processor; the isolation module is configured to transmit the voltage signal transmitted by the switch module to the processor.

7. The sampling circuit according to claim 6, characterized in that: The isolation module includes an isolation unit and a differential unit; The input end of the isolation unit is connected to the switch module, and the isolation unit is configured to output a first sub-voltage signal and a second sub-voltage signal after differentiating the voltage signal; The input end of the differential unit is respectively connected to the first output end and the second output end of the isolation unit, the output end of the differential unit is connected to the processor, and the differential unit is configured to output the difference between the first sub-voltage signal and the second sub-voltage signal to the processor.

8. The sampling circuit according to claim 7, characterized in that: The isolation unit includes an isolation amplifier, a fourth resistor, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor and a fifth capacitor; The fourth resistor is connected between the switch module and the input terminal of the isolation amplifier; The input terminal of the isolation amplifier is also grounded through the first capacitor; The first power supply terminal of the isolation amplifier is connected to the first power supply, the first power supply terminal of the isolation amplifier is also grounded through the second capacitor, and the third capacitor is connected in parallel with the second capacitor; The second power supply terminal of the isolation amplifier is connected to the third power supply, the second power supply terminal of the isolation amplifier is also grounded through the fourth capacitor, and the fifth capacitor is connected in parallel with the fourth capacitor.

9. The sampling circuit according to claim 7, characterized in that: The differential unit includes a differential amplifier, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor and a sixth capacitor; The first input end of the differential amplifier is connected to the first output end of the isolation unit through the fifth resistor, the second input end of the differential amplifier is connected to the second output end of the isolation unit through the sixth resistor, and the output end of the differential amplifier is connected to the processor; The first input terminal of the differential amplifier is also grounded through the seventh resistor, and the first input terminal of the differential amplifier is also grounded through the sixth capacitor; The eighth resistor is connected between the output terminal of the differential amplifier and the second input terminal of the differential amplifier.

10. The sampling circuit according to claim 1, characterized in that: The input module includes a plurality of ninth resistors; The first end of the ninth resistor is connected to the sampling signal, the second end of the ninth resistor is grounded, and the first end of the ninth resistor is also connected to the switch module.

Images