Constant current control circuit and device

Abstract

The utility model relates to a constant current control circuit and device. The constant current control circuit comprises a control module, a constant current module, a power supply module, a first isolation module and a second isolation module, the control module is used for controlling the size of the output signal, performing digital-to-analog conversion on the output signal and then outputting the output signal; the constant current module is used for providing constant output current for the load; the power module is used for supplying power to the control module and the constant-current module; the first isolation module is used for isolating the analog signal output by the control module and providing the analog signal to the constant current module; the second isolation module is used for isolating electrical connection between the power input loop and the power output loop. According to the constant-current control circuit, the isolation module is arranged, so that the anti-interference capability of the constant-current control circuit is improved, the stability of the output current is improved, and stable work of a load is facilitated.

Description

Technical Field

[0001] The present disclosure relates to the technical field of electronic circuits, and in particular to a constant current control circuit and device. Background Art

[0002] The constant current control circuit is a type of circuit currently used in many devices. The constant current control circuit requires the output current to remain constant, thereby providing a stable power supply current to the load.

[0003] When the constant current control circuit is working, it will use the device to feedback the current input to the load and dynamically adjust the power supply state of the circuit, so that the power supply current tends to be constant. However, the constant current control circuit widely used at present is easily disturbed and affected by the external environment, and has poor anti-interference ability. For example, if there are interference signals such as static electricity and electromagnetic waves in the external environment, it will affect the current output, resulting in unstable power supply current and affecting the operation of the load. Utility Model Content

[0004] In order to solve the above technical problem or at least partially solve the above technical problem, the present disclosure provides a constant current control circuit and a device.

[0005] In a first aspect, the present disclosure provides a constant current control circuit, comprising: a control module, a constant current module, a power module, a first isolation module and a second isolation module;

[0006] The first isolation module is electrically connected between the control module and the constant current module; the second isolation module is arranged in the power module; the power module is electrically connected to the control module and the constant current module respectively;

[0007] The control module is used to control the size of the output signal and output the output signal after digital-to-analog conversion; the constant current module is used to provide a constant output current for the load; the power module is used to power the control module and the constant current module; the first isolation module is used to isolate the analog signal output by the control module and provide it to the constant current module; the second isolation module is used to isolate the electrical connection between the power input circuit and the power output circuit.

[0008] In some embodiments, the control module includes a digital-to-analog conversion unit;

[0009] The input end of the first isolation module is electrically connected to the output end of the digital-to-analog conversion unit; the output end of the first isolation module is electrically connected to the input end of the constant current module;

[0010] The digital-to-analog conversion unit is integrated in the control module and is used to convert the output signal from a digital signal to an analog signal for output.

[0011] In some embodiments, the second isolation module includes a signal input side and a signal output side;

[0012] The signal input side includes a first input terminal and a second input terminal; the first input terminal is connected to an external power supply terminal to provide an analog power supply voltage; the second input terminal is connected to an analog ground; the circuit where the signal input side of the second isolation module is located constitutes a power input loop for powering the constant current module;

[0013] The signal output side includes a first output terminal and a second output terminal; the first output terminal provides a digital power supply voltage; the second output terminal is connected to a digital ground; the circuit where the signal output side of the second isolation module is located constitutes a power output loop for powering the control module.

[0014] In some embodiments, the first isolation module includes: a first operational amplifier, a linear optocoupler, and a second operational amplifier;

[0015] The first operational amplifier is electrically connected between the control module and the linear optocoupler; the second operational amplifier is electrically connected between the linear optocoupler and the constant current module;

[0016] The linear optocoupler is used to isolate the analog signal output by the control module; the first operational amplifier and the second operational amplifier are used to make the output signal of the first isolation module follow the change of the input signal of the first isolation module.

[0017] In some embodiments, the inverting input terminal of the first operational amplifier is electrically connected to the output terminal of the control module and the third pin of the linear optocoupler respectively; the output terminal of the first operational amplifier is electrically connected to the first pin of the linear optocoupler; the non-inverting input terminal of the first operational amplifier and the fourth pin of the linear optocoupler are connected to the digital ground; the second pin of the linear optocoupler is electrically connected to the power module;

[0018] The sixth pin of the linear optocoupler is electrically connected to the inverting input terminal and the output terminal of the second operational amplifier respectively; the fifth pin of the linear optocoupler and the non-inverting input terminal of the second operational amplifier are both connected to the analog ground; the output terminal of the second operational amplifier is also electrically connected to the output terminal of the constant current module.

[0019] In some embodiments, further comprising a communication module;

[0020] The communication module is electrically connected to the control module and the power module respectively; the communication module sends a corresponding electrical signal to the control module based on the received communication signal; the control module controls the size of the output signal based on the electrical signal, and outputs the output signal after digital-to-analog conversion; the power module supplies power to the communication module.

[0021] In some embodiments, the communication module further includes a network interface; the network interface is used to plug in an external control device and transmit a communication signal sent by the external control device.

[0022] In some embodiments, the constant current module includes a third operational amplifier, a switch element, a first resistor and a sampling resistor;

[0023] The control end of the switch element is connected to the output end of the third operational amplifier; the first end of the switch element is electrically connected to the inverting input end of the third operational amplifier through a first resistor; the first end of the sampling resistor is electrically connected between the first resistor and the first end of the switch element; the second end of the sampling resistor is connected to the analog ground; and the second end of the switch element is electrically connected to the load.

[0024] In some embodiments, the constant current module further includes a low-pass filtering unit;

[0025] The low-pass filtering unit includes a second resistor and a first capacitor;

[0026] The second resistor is connected in series between the output end of the third operational amplifier and the control end of the switching element; the first end of the first capacitor is electrically connected between the output end of the third operational amplifier and the first end of the second resistor; the second end of the first capacitor is electrically connected between the inverting input end of the third operational amplifier and the first end of the first resistor.

[0027] In a second aspect, the present disclosure further provides a constant current control device, comprising a constant current control circuit as described in any one of the first aspects.

[0028] Compared with the prior art, the technical solution provided by the present invention has the following advantages:

[0029] The constant current control circuit in the present disclosure includes: a control module, a constant current module, a power module, a first isolation module and a second isolation module; the control module is used to control the size of the output signal, and output the output signal after digital-to-analog conversion; the constant current module is used to provide a constant output current for the load; the power module is used to power the control module and the constant current module; the first isolation module is used to isolate the analog signal output by the control module and provide it to the constant current module; the second isolation module is used to isolate the electrical connection between the power input circuit and the power output circuit. Thus, the control module converts the signal to be output from a digital signal to an analog signal and inputs it into the first isolation module, the first isolation module isolates the signal, and outputs the isolated analog signal, which is provided to the constant current module, and the constant current module provides a constant output current to the load based on this signal. By isolating the output signal of the control module by the first isolation module, the anti-interference ability of the signal can be improved, and the stability of the constant current can be provided. A second isolation module is also provided in the power module to isolate the power input circuit and the output circuit of the power module, so as to avoid the circuit on one side being affected by the external interference signal, causing the circuit on the other side to be affected, thereby affecting the signal transmission stability of the circuit where the control circuit is located. The present disclosure improves the anti-interference capability of the constant current control circuit by setting an isolation module, thereby improving the stability of the output current, which is beneficial to the stable operation of the load. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0032] Figure 1 A structural schematic diagram of a constant current control circuit provided by an embodiment of the present disclosure;

[0033] Figure 2 A structural schematic diagram of another constant current control circuit provided in an embodiment of the present disclosure;

[0034] Figure 3 A structural schematic diagram of another constant current control circuit provided in an embodiment of the present disclosure;

[0035] Figure 4 A structural schematic diagram of another constant current control circuit provided in an embodiment of the present disclosure;

[0036] Figure 5A structural schematic diagram of another constant current control circuit provided in an embodiment of the present disclosure;

[0037] Figure 6 A structural schematic diagram of another constant current control circuit provided in an embodiment of the present disclosure;

[0038] Figure 7 A schematic diagram of the structure of an NMOS type switch element provided in an embodiment of the present disclosure.

[0039] Among them, 10, control module; 20, constant current module; 30, power module; 40, first isolation module; 50, second isolation module; 60, communication module; 11, digital-to-analog conversion unit; L1, first inductor; L2, second inductor; C1-C7, first capacitor-seventh capacitor; D1, diode; D2, anti-reverse diode; first resistor-seventh resistor, R1-R7; Rt, sampling resistor; F1, first fuse; F2, second fuse, U1, first operational amplifier; U2, second operational amplifier; U3, third operational amplifier; U4, linear optocoupler; Q1, switching element. DETAILED DESCRIPTION

[0040] In order to more clearly understand the above-mentioned objectives, features and advantages of the present disclosure, the scheme of the present disclosure will be further described below. It should be noted that the embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0041] In the following description, many specific details are set forth to facilitate a full understanding of the present disclosure, but the present disclosure may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present disclosure, rather than all of the embodiments.

[0042] Figure 1 A constant current control circuit is provided in an embodiment of the present disclosure. The constant current control circuit includes: a control module 10 , a constant current module 20 , a power module 30 , a first isolation module 40 and a second isolation module 50 .

[0043] The first isolation module 40 is electrically connected between the control module 10 and the constant current module 20 ; the second isolation module 50 is disposed in the power module 30 ; and the power module 30 is electrically connected to the control module and the constant current module respectively.

[0044] The control module 10 is used to control the size of the output signal and output the output signal after digital-to-analog conversion; the constant current module 20 is used to provide a constant output current for the load; the power module 30 is used to power the control module 10 and the constant current module 20; the first isolation module 40 is used to isolate the analog signal output by the control module 10 and provide it to the constant current module 20; the second isolation module 50 is used to isolate the electrical connection between the power input circuit and the power output circuit.

[0045] The output end of the control module 10 is electrically connected to the input end of the first isolation module 40, and the output end of the first isolation module 40 is electrically connected to the input end of the constant current module 20. The control module 10 can control the size of the output signal, and the output signal can determine the size of the output current of the constant current module 20, and the constant current module 20 is used to provide a constant output current for the load.

[0046] Since the output signal directly output by the control module 10 is a digital signal, and the constant current module needs to receive an analog signal, the control module 10 will also perform digital-to-analog conversion on the output signal before outputting the signal to the first isolation module 40, and output the analog output signal to the first isolation module 40. A digital circuit is provided in the control module 10, and the digital circuit is easily affected by external interference, resulting in unstable signal transmission. For example, external noise, electromagnetic waves, etc. will affect the signal transmission in the digital circuit, thereby affecting the output signal of the control module 10 and interfering with the stability of the final output current. Therefore, it is necessary to isolate the output signal of the control module 10, isolate the signal in the control module 10 from the signal in the constant current module 20, prevent the constant current module 20 from being affected by the external environment, and prevent the control module 10 from being affected, so as to avoid the circuits on both sides from interfering with each other or causing circuit failures, and affecting the stability of the constant current control circuit.

[0047] The power module 30 is electrically connected to the control module 10 and the constant current module 20 respectively to provide the power required for their work. However, the control module 10 is provided with a digital circuit, and the constant current module 20 is provided with an analog circuit. Similarly, in order to avoid external interference signals affecting the stability of the constant current control circuit during power supply, a second isolation module 50 is provided in the power module 30. The electrical connection between the power input circuit and the power output circuit is isolated by the second isolation module 50. The power input circuit and the power output circuit can provide the required power for modules with different needs, which can ensure that the circuits on both sides of the power module 30 will not interfere with each other, will not interfere with the signal transmission between the control module 10 and the constant current module 20, and can provide the stability of the constant current control circuit.

[0048] The control module in the embodiment of the present disclosure converts the signal to be output from a digital signal to an analog signal and then inputs it into the first isolation module. The first isolation module isolates the signal and outputs the isolated analog signal, which is provided to the constant current module. The constant current module provides a constant output current to the load based on this signal. By isolating the output signal of the control module by the first isolation module, the anti-interference ability of the signal can be improved and the stability of the constant current can be provided. A second isolation module is also provided in the power supply module to isolate the power input circuit and the output circuit of the power supply module to prevent the circuit on one side from being affected by external interference signals, causing the circuit on the other side to be affected, thereby affecting the signal transmission stability of the circuit where the control circuit is located. The present disclosure improves the anti-interference ability of the constant current control circuit by setting an isolation module, thereby improving the stability of the output current, which is conducive to stable operation of the load.

[0049] In some embodiments, Figure 2 FIG. 1 is a structural diagram of another constant current control circuit provided in an embodiment of the present disclosure, such as Figure 2 As shown, the control module 10 includes a digital-to-analog conversion unit 11 .

[0050] The input end of the first isolation module 40 is electrically connected to the output end of the digital-to-analog conversion unit 11; the output end of the first isolation module 40 is electrically connected to the input end of the constant current module 20; the digital-to-analog conversion unit 11 is integrated in the control module 10, and is used to convert the output signal from a digital signal to an analog signal and then output it.

[0051] Exemplarily, the control module 10 is integrated with a digital-to-analog conversion unit 11, and the output signal of the control module 10 is converted from a digital signal to an analog signal in the digital-to-analog conversion unit 11, and output to the first isolation module 40, and transmitted to the constant current module 20 after isolation by the first isolation module 40. For example, the control module 10 is an MCU (Microcontroller Unit), and a DAC (Digital-to-Analog Converter) is provided in the MCU. The MCU determines the size of the output signal according to the reference voltage, and performs digital-to-analog conversion on the output signal through the DAC, and converts the output signal from a digital signal to an analog signal. The output signals mentioned here can all be voltage signals. The digital-to-analog conversion unit is integrated in the control module, which can save space, reduce the volume of the circuit structure, and is conducive to circuit modularization and miniaturization.

[0052] In some optional embodiments, the digital-to-analog conversion unit can also be set as a separate module, which is electrically connected to the control module. After the control module inputs the output signal to the separately set digital-to-analog conversion unit, the digital-to-analog conversion unit processes and outputs the analog signal. By using a separately set module, circuit structures of different types and parameters can be matched according to needs, and there are more choices in circuit connection. It should be noted that the embodiments of the present disclosure do not limit the specific position and structure of the digital-to-analog conversion unit. The above embodiments are only for example illustration and can be selected according to actual needs.

[0053] In some embodiments, the second isolation module includes a signal input side and a signal output side.

[0054] The signal input side includes a first input terminal and a second input terminal; the first input terminal is connected to an external power supply terminal to provide an analog power supply voltage; the second input terminal is connected to an analog ground; the circuit where the signal input side of the second isolation module is located constitutes a power input loop for powering the constant current module.

[0055] The signal output side includes a first output terminal and a second output terminal; the first output terminal provides a digital power supply voltage; the second output terminal is connected to a digital ground; the circuit where the signal output side of the second isolation module is located constitutes a power output loop for powering the control module.

[0056] For example, Figure 3 A schematic diagram of another display module selected for the embodiment of the present disclosure, referring to Figure 3 The first pin 1 to the third pin 3 of the second isolation module 50 is the signal input side, and the fifth pin 5 to the eighth pin 8 is the signal output side. The signal input side includes a first input terminal and a second input terminal. The first input terminal is the second pin 2, which is connected to the external power supply terminal and is used to provide an analog power supply voltage. Figure 5 In the example, a 5V voltage is provided, and the specific voltage value can be set according to actual needs. The second input end is the first pin 1, which is connected to the analog ground GND. Therefore, the circuit where the signal input side of the second isolation module 50 is located constitutes a power input loop, which can provide an analog voltage signal for the analog circuit. The constant current module 20 transmits an analog signal, so the power input loop is used to power the constant current module 20, that is, the device in the constant current module 20 that needs to be powered by the power module 30 can be electrically connected to the 5V analog voltage.

[0057] The signal output side includes a first output terminal and a second output terminal, wherein the first output terminal is the sixth pin 6, which isolates the input voltage signal and provides a digital power supply voltage, for example, outputs a 5V-A voltage, and the specific voltage value is determined according to the voltage on the signal input side, and the second output terminal is the seventh pin 7, which is connected to the digital ground GND-A. Therefore, the circuit where the signal output side of the second isolation module 50 is located constitutes a power supply output loop, which can provide a digital power supply voltage for the digital circuit. The control module 10 transmits a digital signal, so the power supply output loop can supply power to the digital circuit part in the control module 10, that is, the device in the control module 10 that needs to be powered by the power module 30 can be electrically connected to the 5V-A digital voltage. In the disclosed embodiment, the second isolation module 50 includes an isolation chip U5, which isolates the electrical connection between the power input loop and the power output loop through the isolation chip U5, so as to prevent the external power supply from being disturbed and affecting one side of the power output loop, thereby affecting the circuit part that needs to be powered by the power output loop, that is, affecting the digital signal transmission of the control module 10.

[0058] In some optional embodiments, continue to refer to Figure 3 , the power module 30 also includes a first fuse F1, a first inductor L1, a second inductor L2, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a third resistor R3 and a diode D1. Among them, a pair of input and output ports of the first fuse F1, the second inductor L2 and the first inductor L1 (common mode inductor) are sequentially connected in series between the external power supply terminal and the first input terminal of the second isolation module 50, one end of the second capacitor C2 is electrically connected between the first inductor L1 and the first input terminal of the second isolation module 50, one end of the third capacitor C3 and one end of the fourth capacitor C4 are respectively electrically connected between the first fuse F1 and the second inductor L2, and one end of the fifth capacitor C5 is electrically connected between the second inductor L2 and the first inductor L1; the other end of the second capacitor C2, the other end of the third capacitor C3, the other end of the fourth capacitor C4, the other end of the fifth capacitor C5 and the other pair of input and output ports of the first inductor L1 are all electrically connected to the analog ground GND. The third resistor R3 and the first diode D1 are sequentially connected in series between the first output terminal of the second isolation module 50 and the digital ground GND-A. For example, the third resistor R3 is 1KΩ, the second capacitor C2, the fourth capacitor CA and the fifth capacitor C5 are 10μF, and the third capacitor C3 is 1000μF. By setting multiple capacitors, inductors and resistors, the circuit is filtered and current limited to reduce interference signals in the circuit and avoid circuit damage.

[0059] It should be noted that the embodiments of the present disclosure do not limit the specific circuit structures of the power module and the second isolation module, which can be set according to actual needs. The above embodiments are only for illustration.

[0060] In some embodiments, Figure 4A structural diagram of another constant current control circuit provided in an embodiment of the present disclosure is shown in FIG. Figure 4 As shown, the first isolation module 40 includes: a first operational amplifier U1 , a linear optocoupler U4 , and a second operational amplifier U2 .

[0061] The first operational amplifier U1 is electrically connected between the control module 10 and the linear optocoupler U4 ; the second operational amplifier U2 is electrically connected between the linear optocoupler U4 and the constant current module 20 .

[0062] The linear optocoupler U4 is used to isolate the analog signal output by the control module 10 ; the first operational amplifier U1 and the second operational amplifier U2 are used to make the output signal of the first isolation module 40 change in accordance with the input signal of the first isolation module 40 .

[0063] Exemplarily, the control module 10 transmits the output signal after digital-to-analog conversion to the inverting input terminal of the first operational amplifier U1, and then transmits it to the linear optocoupler U4, and isolates it in the linear optocoupler U4. The linear optocoupler U4 outputs the isolated analog signal to the second operational amplifier U2, and the second operational amplifier outputs it to the constant current module 20. By setting the linear optocoupler U4, the analog signal output by the control module 10 is isolated, and the stability and anti-interference ability of the circuit are improved. Since the embodiment of the present disclosure is only for isolating the signal, there is no need to change the size of the output signal. Therefore, the first operational amplifier U1 and the second operational amplifier U2 are also provided to form a voltage follower unit, so that the size of the output signal of the second operational amplifier U2 changes with the size of the input signal of the first operational amplifier U1, even if the output signal of the first isolation module 40 changes with the input signal of the first isolation module 40. For example, the output signal of the control module 10 is Vin, and the signal output to the constant current module 20 is Vout, where Vout=Vin.

[0064] In some embodiments, continue to refer to Figure 4 , the inverting input terminal of the first operational amplifier U1 is electrically connected to the output terminal of the control module 10 and the third pin of the linear optocoupler U4 respectively; the output terminal of the first operational amplifier U1 is electrically connected to the first pin of the linear optocoupler U4; the non-inverting input terminal of the first operational amplifier U1 and the fourth pin of the linear optocoupler U4 are connected to the digital ground; the second pin of the linear optocoupler U4 is electrically connected to the power module;

[0065] The sixth pin of the linear optocoupler U4 is electrically connected to the inverting input and output of the second operational amplifier U2 respectively; the fifth pin of the linear optocoupler U4 and the non-inverting input of the second operational amplifier U2 are both connected to the analog ground; the output of the second operational amplifier U2 is also electrically connected to the output of the constant current module 20.

[0066] Exemplarily, the output signal of the control module 10 is transmitted from the inverting input terminal of the first operational amplifier U1 to the third pin of the linear optocoupler U4, and the sine input terminal of the first operational amplifier U1 is connected to the digital ground. The output signal is isolated in the linear optocoupler U4 to avoid mutual influence of the signals on both sides. The sixth pin of the linear optocoupler U4 is electrically connected to the inverting input terminal and the output terminal of the second operational amplifier U2, respectively, so the linear optocoupler U4 transmits the isolated output signal from the inverting input terminal of the second operational amplifier U2 to the constant current module 20.

[0067] Continue to refer Figure 4 , the first isolation module 40 also includes a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7 and a sixth capacitor C6, wherein the fourth resistor is arranged between the output end of the control module 10 and the inverting input end of the first operational amplifier U1, the fifth resistor R5 is arranged between the output end of the first operational amplifier U1 and the linear optocoupler U4, the sixth resistor R6 is arranged between the inverting input end and the output end of the second operational amplifier U2, the seventh resistor R7 is arranged between the output end of the second operational amplifier U2 and the constant current module 20, one end of the sixth capacitor C6 is electrically connected between the output end of the control module and the first end of the fourth resistor R4, and the other end is connected to the digital ground. For example, the fourth resistor R4 and the sixth resistor R6 are 32KΩ, the fifth resistor R5 is 200Ω, the seventh resistor R7 is 470Ω, and the sixth capacitor C6 is 10μF. Among them, the output signal (voltage signal) of the control module is Vin, and the signal (voltage signal) transmitted to the constant current module 20 is Vout, Vout = K*(R6 / R4)*Vin, K is the proportional coefficient of the linear optocoupler U4, which is a known number, and the typical value is K=1. The purpose of the embodiment of the present disclosure is only isolation, and there is no need to change the signal value, so the fourth resistor R4 and the sixth resistor R6 are combined with the first operational amplifier U1 and the second operational amplifier U2 to achieve the purpose of voltage following. The remaining resistors and capacitors can be used to filter clutter and limit current.

[0068] It should be noted that the embodiments of the present disclosure do not limit the specific circuit structure of the first isolation module, which can be set according to actual needs. The above embodiments are only examples, and the above embodiments may also include other circuit structures constituting the first isolation module, or select electronic components with other parameters.

[0069] In some embodiments, Figure 5 A structural diagram of another constant current control circuit provided in the embodiment of the present disclosure, referring to Figure 5 , the constant current control circuit also includes a communication module 60.

[0070] The communication module 60 is electrically connected to the control module 10 and the power module 30 respectively; the communication module 60 sends a corresponding electrical signal to the control module 10 based on the received communication signal; the control module 10 controls the size of the output signal based on the electrical signal, and outputs the output signal after digital-to-analog conversion; the power module 30 supplies power to the communication module 60.

[0071] Since the prior art mostly determines the size of the output signal of the control module 10 by a fixed reference voltage, thereby determining the output current of the constant current module 20, the application scenario is relatively single and cannot match a variety of different types of loads. Therefore, the embodiment of the present disclosure further provides a communication module 60 in the constant current control circuit, which changes the size of the output current by communication so as to be applicable to a variety of devices.

[0072] Specifically, the communication module is electrically connected to the control module 10, and the communication module 60 sends a corresponding electrical signal to the control module 10 based on the received communication signal. The control module 10 controls the size of the output signal according to the received electrical signal. When the output current of the constant current module 20 needs to be changed, different communication signals can be sent. The communication module 60 sends a corresponding electrical signal to the control module 10 based on different communication signals, thereby changing the size of the output signal of the control module 10 and changing the output current of the constant current module 20. The communication module 60 can be connected to an electronic device, such as a computer or a switch, and the user can send a communication signal through the computer or switch interface, or the communication module 60 can access a network, such as Ethernet, and send a communication signal through a remote communication method. The communication module 60 is also electrically connected to the power module 30, and the power module 30 supplies power to the communication module 60.

[0073] In some embodiments, the communication module also includes a network interface; the network interface is used to plug in an external control device and transmit the communication signal sent by the external control device. The communication module is provided with a network interface, and the network interface can be plugged into an external control device. The external control device sends a communication signal to the communication module and transmits it to the control module through the network interface. For example, the interface can be RJ45, so that a computer or a switch is connected to the communication module through RJ45 to send a signal to the control module. In some other embodiments, the network interface can also be other types of interfaces, and the above RJ45 is only for example, and the specific interface type can match the device that sends the communication signal.

[0074] In some embodiments, Figure 6 A structural diagram of another constant current control circuit provided in an embodiment of the present disclosure; Figure 6 The constant current module 20 includes a third operational amplifier U3, a switch element Q1, a first resistor R1 and a sampling resistor Rt.

[0075] The control end of the switch element Q1 is connected to the output end of the third operational amplifier U3; the first end of the switch element Q1 is electrically connected to the inverting input end of the third operational amplifier U3 through the first resistor R1; the first end of the sampling resistor Rt is electrically connected between the first resistor R1 and the first end of the switch element Q1; the second end of the sampling resistor Rt is connected to the analog ground; and the second end of the switch element Q1 is electrically connected to the load.

[0076] Exemplarily, in the constant current module 20, the in-phase input terminal of the third operational amplifier U3 is electrically connected to the output terminal of the first isolation module 40 to receive the isolated analog signal, the output terminal of the third operational amplifier is electrically connected to the control terminal of the switch element Q1, and the signal output by the third operational amplifier is used to control the on and off of the switch element Q1. The inverting input terminal of the third operational amplifier U3 is electrically connected to the output terminal of the third operational amplifier U3, and the inverting input terminal of the third operational amplifier U3 is also electrically connected to the first end of the switch element Q1 through the first resistor R1, and the second end of the switch element Q1 is electrically connected to the load, and the switch element Q1 is connected in series in the circuit loop where the load is located. The first end of the sampling resistor Rt is electrically connected between the first resistor R1 and the first end of the switch element Q1; the second end of the sampling resistor Rt is connected to the analog ground, and the output signal of the third operational amplifier U3 is automatically adjusted by detecting the voltage of the sampling resistor Rt and feeding it back to the inverting input terminal of the third operational amplifier U3.

[0077] Specifically, Figure 7 A schematic diagram of the structure of an NMOS type switch element provided in an embodiment of the present disclosure, referring to Figure 6 and Figure 7 , the switch element Q1 is an NMOS switch element, the sampling resistor Rt is 10Ω, and the first resistor R1 is 220Ω. The MOS tube uses the voltage between the gate (control terminal) and the source (first terminal) to control the current passing through the load. For NMOS, when the gate-source voltage Vgs>Vgs(th), the NMOS tube is turned on, and Vgs(th) is the conduction proximity value of the NMOS tube. If a certain voltage is added between the D pole and the S pole, the load will have a current Id. Under a certain source-drain voltage Vds, the D pole current Id is related to the G pole voltage Vgs, and the output end of the third operational amplifier U3 is electrically connected to the control end of Q1, which is equivalent to the output end of the third operational amplifier U3 controlling the drain current Id of the switch element Q1. Based on the characteristics of the operational amplifier, the non-inverting input end of the third operational amplifier U3 controls the magnitude of its output terminal voltage, so by adjusting the input signal of the non-inverting input end of the third operational amplifier U3, the magnitude of the output terminal voltage can be controlled to control the conduction and shutdown of the switch element Q1.

[0078] The inverting input terminal of the third operational amplifier U3 is electrically connected to the sampling resistor Rt through the first resistor R1, and the first terminal (source) of the switch element Q1 is electrically connected between the first resistor R1 and the sampling resistor Rt. The voltage of the sampling resistor Rt can be fed back to the inverting input terminal of the third operational amplifier U3 through the first resistor R1. When the voltage signal of the in-phase input terminal of the third operational amplifier U3 remains unchanged, the negative feedback circuit composed of the first resistor R1, the switch element Q1 and the sampling resistor Rt will automatically adjust so that the voltage on the sampling resistor Rt remains unchanged, and the current remains unchanged, so that the current Id passing through the load also remains unchanged, achieving the purpose of constant current. Specifically, it can be combined with the virtual short and virtual break principles of the operational amplifier. When the operational amplifier is dynamically balanced, the voltage Vin+ of the in-phase input terminal and the voltage Vin- of the inverting input terminal of the operational amplifier will be stable and equal, that is, Vin+=Vin-=Vs, Vs is the sampling resistor voltage, so that the sampling resistor is the current Is stable, and the load current Id will also keep the temperature unchanged, achieving the effect of constant current. Therefore, the purpose of changing the output signal size of the first isolation module 40 can be achieved by changing the size of the output signal of the control module 10, thereby changing the size of the voltage Vs on the sampling resistor Rt and adjusting the load current Id to match the current requirements of different devices. The output signals mentioned here are all voltage signals, and the same is true for the above text, so they will not be repeated.

[0079] In some embodiments, continue to refer to Figure 6 The constant current module 20 also includes a low-pass filtering unit; the low-pass filtering unit includes a second resistor R2 and a first capacitor C1.

[0080] The second resistor R2 is connected in series between the output end of the third operational amplifier U3 and the control end of the switch element Q1; the first end of the first capacitor C1 is electrically connected between the output end of the third operational amplifier U3 and the first end of the second resistor R2; the second end of the first capacitor C1 is electrically connected between the inverting input end of the third operational amplifier U3 and the first end of the first resistor R1.

[0081] By setting the second resistor R2 and the first capacitor C1 to form a low-pass filter unit, the signal output by the third operational amplifier U3 will be filtered before being input into the switching element Q1, filtering out specific frequency signals in the signal to interfere with the circuit, and preventing self-excitation and avoiding component damage.

[0082] In some optional embodiments, the constant current module further includes a second fuse F2, a seventh capacitor C7 and an anti-reverse diode D2. The second fuse F2 is connected in series with the load to prevent the circuit from burning, the anti-reverse diode D2 is connected in parallel to the load to prevent current backflow, and the seventh capacitor C7 is a bypass capacitor for filtering interference signals. It should be noted that the embodiments of the present disclosure do not limit the specific structure of the constant current module, the above embodiments are only for example illustration, and other circuit structures may also be included.

[0083] The present disclosure also provides a constant current control device, including the constant current control circuit as described in any of the above embodiments. Therefore, it has the same or corresponding beneficial effects as the constant current control circuit described in the above embodiments. It should be noted that the constant current control device provided in the present disclosure may also include other circuits and devices for supporting its normal operation, and this embodiment does not specifically limit this.

[0084] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0085] The above description is only a specific embodiment of the present disclosure, so that those skilled in the art can understand or implement the present disclosure. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure will not be limited to the embodiments described herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A constant current control circuit, characterized in that: include: A control module, a constant current module, a power module, a first isolation module and a second isolation module; The first isolation module is electrically connected between the control module and the constant current module; the second isolation module is arranged in the power module; the power module is electrically connected to the control module and the constant current module respectively; The control module is used to control the size of the output signal and output the output signal after digital-to-analog conversion; the constant current module is used to provide a constant output current for the load; the power module is used to power the control module and the constant current module; the first isolation module is used to isolate the analog signal output by the control module and provide it to the constant current module; the second isolation module is used to isolate the electrical connection between the power input circuit and the power output circuit.

2. The constant current control circuit according to claim 1, characterized in that: The control module includes a digital-to-analog conversion unit; The input end of the first isolation module is electrically connected to the output end of the digital-to-analog conversion unit; the output end of the first isolation module is electrically connected to the input end of the constant current module; The digital-to-analog conversion unit is integrated in the control module and is used to convert the output signal from a digital signal to an analog signal for output.

3. The constant current control circuit according to claim 1, characterized in that: The second isolation module includes a signal input side and a signal output side; The signal input side includes a first input terminal and a second input terminal; the first input terminal is connected to an external power supply terminal to provide an analog power supply voltage; the second input terminal is connected to an analog ground; the circuit where the signal input side of the second isolation module is located constitutes a power input loop for powering the constant current module; The signal output side includes a first output terminal and a second output terminal; the first output terminal provides a digital power supply voltage; the second output terminal is connected to a digital ground; the circuit where the signal output side of the second isolation module is located constitutes a power output loop for powering the control module.

4. The constant current control circuit according to claim 1, characterized in that: The first isolation module includes: a first operational amplifier, a linear optocoupler, and a second operational amplifier; The first operational amplifier is electrically connected between the control module and the linear optocoupler; the second operational amplifier is electrically connected between the linear optocoupler and the constant current module; The linear optocoupler is used to isolate the analog signal output by the control module; the first operational amplifier and the second operational amplifier are used to make the output signal of the first isolation module change in accordance with the input signal of the first isolation module.

5. The constant current control circuit according to claim 4, characterized in that: The inverting input terminal of the first operational amplifier is electrically connected to the output terminal of the control module and the third pin of the linear optocoupler respectively; the output terminal of the first operational amplifier is electrically connected to the first pin of the linear optocoupler; the non-inverting input terminal of the first operational amplifier and the fourth pin of the linear optocoupler are connected to the digital ground; the second pin of the linear optocoupler is electrically connected to the power supply module; The sixth pin of the linear optocoupler is electrically connected to the inverting input terminal and the output terminal of the second operational amplifier respectively; the fifth pin of the linear optocoupler and the non-inverting input terminal of the second operational amplifier are both connected to the analog ground; the output terminal of the second operational amplifier is also electrically connected to the output terminal of the constant current module.

6. The constant current control circuit according to claim 1, characterized in that: Also includes a communication module; The communication module is electrically connected to the control module and the power module respectively; the communication module sends a corresponding electrical signal to the control module based on the received communication signal; the control module controls the size of the output signal based on the electrical signal, and outputs the output signal after digital-to-analog conversion; the power module supplies power to the communication module.

7. The constant current control circuit according to claim 6, characterized in that: The communication module also includes a network interface; the network interface is used to plug in an external control device and transmit a communication signal sent by the external control device.

8. The constant current control circuit according to claim 1, characterized in that: The constant current module includes a third operational amplifier, a switch element, a first resistor and a sampling resistor; The control end of the switch element is connected to the output end of the third operational amplifier; the first end of the switch element is electrically connected to the inverting input end of the third operational amplifier through a first resistor; the first end of the sampling resistor is electrically connected between the first resistor and the first end of the switch element; the second end of the sampling resistor is connected to the analog ground; and the second end of the switch element is electrically connected to the load.

9. The constant current control circuit according to claim 8, characterized in that: The constant current module also includes a low-pass filtering unit; The low-pass filtering unit includes a second resistor and a first capacitor; The second resistor is connected in series between the output end of the third operational amplifier and the control end of the switching element; the first end of the first capacitor is electrically connected between the output end of the third operational amplifier and the first end of the second resistor; the second end of the first capacitor is electrically connected between the inverting input end of the third operational amplifier and the first end of the first resistor.

10. A constant current control device, characterized in that: Comprising a constant current control circuit as described in any one of claims 1-9.

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