Current detection circuit capable of long-distance transmission

Abstract

The embodiment of the invention discloses a current detection circuit capable of long-distance transmission. According to the circuit, an obtained initial current signal is amplified through an amplification module and then sent to a PWM generation module, the PWM generation module converts the received current signal into PWM signals with different duty ratios in direct proportion to current, and the PWM signals are transmitted to a level conversion module; and after receiving the PWM signal, the level conversion module performs level conversion on the PWM signal according to the actual level requirement of the target load, further transmits the converted level signal to the alarm module, and finally performs real-time detection on the converted level signal according to the alarm module, thereby realizing current detection capable of long-distance transmission. According to the utility model, the purposes of long-distance stable transmission and accurate detection are achieved by utilizing the characteristics of strong anti-interference capability and long transmission distance of the PWM signal, and the requirements of timely alarming when an overcurrent fault occurs and preventing continuous damage of target load equipment by overcurrent are met through the arranged alarm module.

Description

Technical Field

[0001] One or more embodiments of this specification relate to the field of current detection technology, and more particularly, to a current detection circuit capable of long-distance transmission. Background Art

[0002] In fields such as industrial control, new energy equipment, and power monitoring, the accuracy, anti-interference capabilities, and real-time performance of current detection circuits directly determine the safety and reliability of the system. Existing current detection circuits generally use voltage transmission. However, due to the operating environment and transmission distance, various interferences during the transmission process often cause current transmission errors, making them unable to meet the requirements of accurate current detection. Summary of the Invention

[0003] To solve the problems existing in the prior art, one or more embodiments of this specification describe a current detection circuit capable of long-distance transmission.

[0004] The present application provides a current detection circuit that can be transmitted over long distances, characterized in that the circuit includes an amplification module, a filtering module, a PWM generation module, a level conversion module and an alarm module, the amplification module is electrically connected to the filtering module, the filtering module is electrically connected to the PWM generation module, the PWM generation module is electrically connected to the level conversion module, and the level conversion module is electrically connected to the alarm module.

[0005] Preferably, the amplification module includes an operational amplifier, an input resistor and a feedback resistor, the first end of the input resistor is electrically connected to the non-inverting input terminal of the operational amplifier U1A, the second end of the input resistor is electrically connected to the input current, the first end of the feedback resistor is electrically connected to the inverting input terminal of the operational amplifier, the second end of the feedback resistor is electrically connected to the output terminal of the operational amplifier, and the output terminal of the operational amplifier is electrically connected to the filtering module.

[0006] Preferably, the filtering module includes a filtering resistor and a first filtering capacitor, the first end of the filtering resistor is electrically connected to the amplification module, the second end of the filtering resistor is electrically connected to the first end of the first filtering capacitor, and the second end of the first filtering capacitor is grounded.

[0007] Preferably, the PWM generation module includes a PWM conversion chip and a timing capacitor, the first input end of the PWM conversion chip is electrically connected to the filtering module, the second input end of the PWM conversion chip is electrically connected to the first end of the timing capacitor, the second end of the timing capacitor is grounded, and the output end of the PWM conversion chip is electrically connected to the level conversion module.

[0008] Preferably, the level conversion module includes a capacitance chip and a second filter capacitor, the first input end of the capacitance chip is electrically connected to the PWM generation module, the second input end of the capacitance chip is electrically connected to the first end of the second filter capacitor, the second end of the second filter capacitor is grounded, and the output end of the capacitance chip is electrically connected to the detection module.

[0009] Preferably, the detection module includes a comparison module, an alarm module and a protection module, the input end of the comparison module is electrically connected to the level conversion module, and the output end of the comparison module is electrically connected to the alarm module and the protection module respectively.

[0010] Preferably, the comparison module includes a comparator and a voltage follower, a first input terminal of the comparator is electrically connected to an output terminal of the voltage follower, and a second input terminal of the comparator is electrically connected to an output terminal of the level conversion module.

[0011] Preferably, the alarm module includes a first transistor and a buzzer, the first end of the first transistor is electrically connected to the positive pole of the power supply, the second end of the first transistor is electrically connected to the output end of the comparison module, the third end of the first transistor is electrically connected to the first end of the buzzer, and the second end of the buzzer is grounded.

[0012] Preferably, the protection module includes a second transistor and a relay, the first end of the second transistor is electrically connected to the positive electrode of the power supply, the second end of the second transistor is electrically connected to the output end of the comparison module, the third end of the second transistor is electrically connected to the first end of the relay, and the second end of the relay is electrically connected to the target load.

[0013] Preferably, the circuit also includes a first pull-up resistor and a second pull-up resistor, the first end of the first pull-up resistor is electrically connected to the positive pole of the power supply, the second end of the first pull-up resistor is electrically connected to the input end of the comparison module, the first end of the second pull-up resistor is electrically connected to the positive pole of the power supply, and the second end of the second pull-up resistor is electrically connected to the input end of the alarm module.

[0014] The beneficial effects of the present invention are: The current detection circuit capable of long-distance transmission provided in the embodiments of this specification first amplifies the initial current signal obtained by the amplification module and then sends it to the PWM generation module. The PWM generation module converts the received current signal into a PWM signal with a different duty cycle proportional to the current and transmits it to the level conversion module. After receiving the PWM signal, the level conversion module performs level conversion on the PWM signal according to the actual level requirement of the target load, further transmits the converted level signal to the alarm module, and finally performs real-time detection of the converted level signal according to the alarm module, thereby realizing long-distance current detection. By utilizing the characteristics of the PWM signal with strong anti-interference ability and long transmission distance, the purpose of long-distance stable transmission and accurate detection is achieved. The alarm module is provided to meet the requirements of timely alarm in the event of an overcurrent fault and prevent the overcurrent from continuously damaging the target load equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0016] Figure 1 This is a schematic diagram of the architecture of a current detection circuit capable of long-distance transmission in a specific implementation of this specification; Figure 2 This is a schematic diagram of a current detection circuit capable of long-distance transmission in the specific implementation of this specification; Figure 3 This is a schematic diagram of a detection flow of a current detection circuit capable of long-distance transmission in the specific implementation of this specification. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application.

[0018] In the following introduction, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. The following introduction provides multiple embodiments of the present application. Different embodiments can be replaced or combined, so the present application can also be considered to include all possible combinations of the same and / or different embodiments described. Therefore, if one embodiment includes features A, B, and C, and another embodiment includes features B and D, then the present application should also be considered to include embodiments containing one or more of all other possible combinations of A, B, C, and D, even though the embodiment may not be clearly described in the following text.

[0019] The following description provides examples and does not limit the scope, applicability, or examples set forth in the claims. Changes may be made to the function and arrangement of the elements described without departing from the scope of the present application. Various examples may appropriately omit, replace, or add various processes or components. For example, the described method may be performed in an order different from the order described, and various steps may be added, omitted, or combined. In addition, features described in some examples may be combined in other examples.

[0020] See also Figure 1 and Figure 2 , Figure 1 FIG1 shows a schematic diagram of the architecture of a current detection circuit capable of long-distance transmission provided by an embodiment of this specification. Figure 2 A schematic diagram of an implementation of a current detection circuit capable of long-distance transmission provided in an embodiment of this specification is shown.

[0021] like Figure 1 、 Figure 2 As shown, the current detection circuit capable of long-distance transmission includes an amplifier module, a filter module, a PWM generation module, a level conversion module, and an alarm module. The amplifier module is electrically connected to the filter module, which is electrically connected to the PWM generation module. The PWM generation module is electrically connected to the level conversion module, which is electrically connected to the alarm module. The amplifier module obtains the initial current signal to be transmitted, amplifies the initial current signal, and sends it to the filter module. The filter module filters and de-noises the received amplified current signal, and then sends the de-noised current signal to the PWM generation module. The PWM generation module converts the received de-noised current signal into a PWM signal with a different duty cycle proportional to the current and transmits it to the level conversion module. After receiving the PWM signal, the level conversion module performs level conversion on the PWM signal according to the actual level requirement of the target load and transmits the converted level signal to the alarm module. The alarm module performs real-time detection of the converted level signal according to a preset level threshold. When the converted level signal does not meet the preset requirement, an alarm is issued and the circuit is isolated, achieving anti-interference long-distance transmission and real-time current detection to protect the downstream target load circuit.

[0022] In one embodiment, the amplification module includes an operational amplifier U1A, input resistors R2 and R4, and feedback resistors R1 and R5. The first end of input resistor R2 is electrically connected to the inverting input of operational amplifier U1A, the second end of input resistor R2 is grounded, the first end of input resistor R4 is electrically connected to the non-inverting input of the operational amplifier, and the second end of input resistor R4 is electrically connected to the input current. The first end of feedback resistor R1 is electrically connected to the inverting input of operational amplifier U1A and feedback resistor R5, respectively. The second end of feedback resistor R1 is electrically connected to the output of operational amplifier U1A. The first end of feedback resistor R5 is electrically connected to the non-inverting input of the operational amplifier, and the second end of feedback resistor R5 is electrically connected to the power supply. Specifically, a capacitor C2 may be connected between feedback resistor R1 and feedback resistor R5. The operational amplifier U1A, input resistors R2 and R4, and feedback resistors R1 and R5 are used to amplify the input current input through the non-inverting input terminal. The feedback resistors R1 and R5 are used to determine the amplification factor. The input resistors R2 and R4 are used to improve the common-mode rejection ratio. The capacitor C2 is used to filter out high-frequency noise and stabilize the power supply.

[0023] In one embodiment, the filter module includes a filter resistor R3 and a first filter capacitor C3, wherein the first end of the filter resistor R3 is electrically connected to the amplifier module, the second end of the filter resistor R3 is electrically connected to the first end of the first filter capacitor C3, and the second end of the first filter capacitor C3 is grounded. The filter resistor R3 is provided to suppress noise, reduce interference between current signals, improve circuit stability, and optimize signal detection accuracy. The first filter capacitor C3 is provided to filter out high-frequency noise, smooth the signal waveform, and improve circuit stability. The amplified current signal transmitted by the amplifier module is filtered and denoised by the filter module to reduce interference for subsequent PWM signal conversion.

[0024] In one embodiment, the PWM generation module includes a PWM conversion chip U1 and a timing capacitor C1. A first input terminal of the PWM conversion chip U1 is electrically connected to the filtering module, a second input terminal of the PWM conversion chip U1 is electrically connected to the first terminal of the timing capacitor C1, and a second terminal of the timing capacitor C1 is grounded. An output terminal of the PWM conversion chip U1 is electrically connected to the level conversion module. The PWM conversion chip U1 converts a received current signal into a PWM signal with a varying duty cycle proportional to the current. The timing capacitor C1 is provided to stabilize the oscillator frequency and output a stable PWM signal.

[0025] Among them, the PWM conversion chip U1 can adopt the LTC6992 chip.

[0026] In one embodiment, the level conversion module includes a capacitance isolation chip U3 and a second filter capacitor C4, C5, the first input end of the capacitance isolation chip U3 is electrically connected to the PWM generation module, the second input end pin 1 of the capacitance isolation chip U3 is electrically connected to the first end of the filter capacitor C4, the second input end pin 8 of the capacitance isolation chip U3 is electrically connected to the first end of the filter capacitor C5, the second ends of the filter capacitors C4 and C5 are grounded respectively, and the output end pin 6 of the capacitance isolation chip U3 is electrically connected to the detection module. The PWM signal is level-converted by the capacitance isolation chip U3 to protect the target load low-voltage device that is subsequently electrically connected. For example, the PWM output of the PWM conversion chip U1 is 5V. If the power supply required by the subsequent single-chip microcomputer system is 3.3V, it is necessary to perform level conversion through the capacitance isolation chip U3 to convert the 5V signal into a 3.3V signal with the same duty cycle. The filter capacitors C4 and C5 are provided to filter out the switching noise during the level conversion process to ensure lossless transmission of the signal between different voltage systems.

[0027] Among them, the isolation chip U3 can use the TXB0104 model chip.

[0028] In one embodiment, the detection module includes a comparison module, an alarm module, and a protection module. The input of the comparison module is electrically connected to the level conversion module, and the output of the comparison module is electrically connected to the alarm module and the protection module, respectively. The comparison module is configured to compare the conversion level transmitted by the level conversion module with a preset level and transmit the comparison result to the alarm module and the protection module, respectively. The alarm module determines whether to issue an alarm based on the received comparison result. The protection module is configured to control the triggering of a relay to disconnect the load circuit when the comparison result indicates that the conversion level exceeds the preset level, thereby preventing continued damage to the equipment due to overcurrent.

[0029] In one embodiment, the comparison module includes a comparator U3A and a voltage follower U2A, wherein a first input terminal of the comparator U3A is electrically connected to an output terminal of the voltage follower U2A, and a second input terminal of the comparator U3A is electrically connected to an output terminal of the level conversion module. Specifically, the comparison module may further include a resistor R13, wherein a preset level is set by the voltage follower U2A and the resistor R13, and the preset level is transmitted to the comparator U3A. The comparator U3A compares the conversion level transmitted by the level conversion module with the preset level transmitted by the voltage follower U2A. When the conversion level exceeds the preset level, the comparator U3A outputs a high level and transmits the comparison result, i.e., a high level signal, to the alarm module and the protection module, respectively.

[0030] In one embodiment, the alarm module includes a first transistor Q1 and a buzzer P1. The first end, i.e., the emitter, of the first transistor Q1 is electrically connected to the positive electrode of the power supply. The second end, i.e., the base, of the first transistor Q1 is electrically connected to the output of the comparison module. The third end, i.e., the collector, of the first transistor Q1 is electrically connected to the first end of the buzzer P1. The second end of the buzzer P1 is grounded. When the output of the comparison module is at a high level, the base of the first transistor Q1 is at a high level, the transistor conducts, and the buzzer P1 turns on, emitting a buzzing sound. The configuration of the first transistor Q1 and the buzzer P1 ensures a hardware-driven operation without software delay, ensuring an immediate alarm as soon as the output of the comparison module is at a high level.

[0031] In one embodiment, the protection module includes a second transistor Q2 and a relay UN. The first end, i.e., the emitter, of the second transistor Q2 is electrically connected to the positive electrode of the power supply. The second end, i.e., the base, of the second transistor Q2 is electrically connected to the output of the comparison module. The third end, i.e., the collector, of the second transistor Q2 is electrically connected to the first end of the relay UN. The second end of the relay UN is electrically connected to the target load P2. Due to the configuration of the second transistor Q2 and relay UN, when the output of the comparison module is at a high level, the base of the second transistor Q2 is at a high level, the transistor conducts, and the relay UN closes, disconnecting the load circuit and preventing continued damage to the device due to overcurrent.

[0032] In one embodiment, the circuit further includes a first pull-up resistor R1 and a second pull-up resistor R6. The first end of the first pull-up resistor R12 is electrically connected to the positive electrode of the power supply, the second end of the first pull-up resistor R1 is electrically connected to the input terminal of the comparison module, the first end of the second pull-up resistor R6 is electrically connected to the positive electrode of the power supply, and the second end of the second pull-up resistor R6 is electrically connected to the input terminal of the alarm module. The first pull-up resistor R1 is provided to prevent false triggering caused by the input terminal being left floating, and the second pull-up resistor R6 is provided to ensure that the comparison result corresponds to a fault signal output at a high level.

[0033] Optionally, R7, R8, R9, R10, R11 and R13 may be provided in the circuit to protect the circuit from short circuit.

[0034] See next Figure 3 , Figure 3 A detection flow diagram of a current detection circuit capable of long-distance transmission provided in an embodiment of this specification is shown.

[0035] See Figure 3 , current detection methods that can be transmitted over long distances include: S301, the amplification module obtains an initial current signal to be transmitted, and transmits the amplified current signal after current amplification of the initial current signal to the filtering module; S302, the filtering module filters and removes noise from the received initial current signal, and transmits the removed noise current signal to the PWM generation module; S303, the PWM generation module converts the de-noised current signal and transmits the converted PWM signal to the level conversion module; S304: The level conversion module generates a conversion level signal based on the received PWM signal and transmits it to the alarm module. The alarm module generates an alarm and disconnects the circuit according to the preset level threshold and the conversion level signal.

[0036] In an embodiment of the present specification, an amplification module obtains an initial current signal to be transmitted, amplifies the initial current signal, and then sends it to a filtering module. The filtering module filters and de-noises the received amplified current signal, and then sends the de-noised current signal to a PWM generation module. The PWM generation module converts the received de-noised current signal into a PWM signal with a different duty cycle that is proportional to the current and transmits it to a level conversion module. After receiving the PWM signal, the level conversion module performs level conversion on the PWM signal according to the actual level requirement of the target load and transmits the converted level signal to an alarm module. The alarm module performs real-time detection of the converted level signal based on a preset level threshold. When the conversion level exceeds the preset level threshold, an alarm is issued and the circuit is isolated, thereby achieving anti-interference long-distance transmission and real-time current detection to protect the subsequent target load circuit. When the conversion level does not exceed the preset level threshold, the alarm module does not generate a fault signal, does not alarm, and the subsequent circuit is closed.

[0037] The above is only an exemplary embodiment of the present disclosure and cannot be used to limit the scope of the present disclosure. That is, any equivalent changes and modifications made according to the teachings of the present disclosure are still within the scope of the present disclosure. After considering the specification and practicing the disclosure herein, those skilled in the art will easily think of the implementation scheme of the present disclosure. This application is intended to cover any variation, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary technical means in the art that are not recorded in the present disclosure. The description and examples are to be regarded as exemplary only, and the scope and spirit of the present disclosure are defined by the claims.

Claims

1. A current detection circuit capable of long-distance transmission, characterized in that: The circuit includes an amplification module, a filtering module, a PWM generation module, a level conversion module and an alarm module. The amplification module is electrically connected to the filtering module, the filtering module is electrically connected to the PWM generation module, the PWM generation module is electrically connected to the level conversion module, and the level conversion module is electrically connected to the alarm module.

2. The circuit according to claim 1, wherein: The amplification module includes an operational amplifier, an input resistor and a feedback resistor. The first end of the input resistor is electrically connected to the non-inverting input terminal of the operational amplifier U1A, the second end of the input resistor is electrically connected to the input current, the first end of the feedback resistor is electrically connected to the inverting input terminal of the operational amplifier, the second end of the feedback resistor is electrically connected to the output terminal of the operational amplifier, and the output terminal of the operational amplifier is electrically connected to the filtering module.

3. The circuit according to claim 1, wherein: The filtering module includes a filtering resistor and a first filtering capacitor, a first end of the filtering resistor is electrically connected to the amplifying module, a second end of the filtering resistor is electrically connected to a first end of the first filtering capacitor, and a second end of the first filtering capacitor is grounded.

4. The circuit according to claim 1, wherein: The PWM generation module includes a PWM conversion chip and a timing capacitor. The first input end of the PWM conversion chip is electrically connected to the filtering module, the second input end of the PWM conversion chip is electrically connected to the first end of the timing capacitor, the second end of the timing capacitor is grounded, and the output end of the PWM conversion chip is electrically connected to the level conversion module.

5. The circuit according to claim 1, wherein: The level conversion module includes a capacitance chip and a second filter capacitor, the first input end of the capacitance chip is electrically connected to the PWM generation module, the second input end of the capacitance chip is electrically connected to the first end of the second filter capacitor, the second end of the second filter capacitor is grounded, and the output end of the capacitance chip is electrically connected to the detection module.

6. The circuit according to claim 1, wherein: The detection module includes a comparison module, an alarm module and a protection module. The input end of the comparison module is electrically connected to the level conversion module, and the output end of the comparison module is electrically connected to the alarm module and the protection module respectively.

7. The circuit according to claim 6, characterized in that The comparison module includes a comparator and a voltage follower, a first input terminal of the comparator is electrically connected to an output terminal of the voltage follower, and a second input terminal of the comparator is electrically connected to an output terminal of the level conversion module.

8. The circuit according to claim 6, characterized in that The alarm module includes a first transistor and a buzzer, the first end of the first transistor is electrically connected to the positive pole of the power supply, the second end of the first transistor is electrically connected to the output end of the comparison module, the third end of the first transistor is electrically connected to the first end of the buzzer, and the second end of the buzzer is grounded.

9. The circuit according to claim 6, characterized in that The protection module includes a second transistor and a relay, wherein the first end of the second transistor is electrically connected to the positive electrode of the power supply, the second end of the second transistor is electrically connected to the output end of the comparison module, the third end of the second transistor is electrically connected to the first end of the relay, and the second end of the relay is electrically connected to the target load.

10. The circuit according to claim 6, characterized in that The circuit also includes a first pull-up resistor and a second pull-up resistor, the first end of the first pull-up resistor is electrically connected to the positive pole of the power supply, the second end of the first pull-up resistor is electrically connected to the input end of the comparison module, the first end of the second pull-up resistor is electrically connected to the positive pole of the power supply, and the second end of the second pull-up resistor is electrically connected to the input end of the alarm module.

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