Current output control circuit and electronic device

Abstract

The present disclosure provides a current output control circuit and electronic equipment, the current output control circuit includes: a control module, a digital-to-analog conversion module, a current output module and a current detection module; the control module sends a control instruction to the digital-to-analog conversion module; the digital-to-analog conversion module outputs a DAC voltage to the current output module according to the control instruction; the current output module outputs current under the action of the DAC voltage; the current detection module detects the current output of the current output module to obtain a detection current value, and sends the detection current value to the control module; the control module also checks whether the detection current value is within a preset current range. The present disclosure adopts all general discrete domestic devices, can efficiently control the current output, and through the current output loop feedback monitoring, improves the overall reliability, reduces damage, reduces costs, and improves system safety. By adjusting some components, different ranges can be set, which increases scalability and expands the module application scenario.

Description

Technical Field

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

[0002] Analog quantity refers to a continuously changing physical quantity, which can be represented by a continuously changing numerical value. Unlike digital quantity (which can only take discrete values, such as 0 and 1), analog quantity can take any value within a certain range.

[0003] In the process of using analog quantity, some key equipment and technologies are involved, including:

[0004] Sensor: The sensor is the primary device for obtaining analog quantities. It can convert various physical quantities into measurable electrical signals. Commonly used sensors include temperature sensors, pressure sensors, humidity sensors, etc.

[0005] Transmitter: A transmitter is a device that converts the output signal of a sensor into a standard signal, such as 4-20mA (milliampere) current and 0-10V voltage. This makes the signal easier to transmit and process.

[0006] A / D converter (analog-to-digital converter): The function of an A / D converter is to convert analog signals into digital signals. In modern electronic systems, digital signal processing technology is more common and efficient, so it is often necessary to convert analog quantities into digital quantities for digital signal processing.

[0007] D / A converter (digital-to-analog converter): In some cases, it is also necessary to convert digital quantities into analog quantities in order to drive analog devices or output analog signals. A D / A converter is a device that realizes this function.

[0008] In the field of instrumentation, current output is often used for signal transmission and measurement. For example, 4-20mA current signals are widely used in industrial automation and process control to transmit data measured by sensors. Currently, there is a lack of current output control circuits that can both control current output and monitor the load current in real time online. Summary of the invention

[0009] The technical problem to be solved by the present disclosure is to overcome the defect in the prior art that there is a lack of a current output control circuit that can both control the current output and monitor the load end current in real time online, and to provide a current output control circuit and an electronic device.

[0010] The present invention solves the above technical problems through the following technical solutions:

[0011] The present disclosure provides a current output control circuit, which comprises: a control module, a digital-to-analog conversion module, a current output module and a current detection module;

[0012] The control module is used to send control instructions to the digital-to-analog conversion module;

[0013] The digital-to-analog conversion module is used to output a DAC voltage to the current output module according to the control instruction;

[0014] The current output module is used to output current under the action of the DAC voltage;

[0015] The current detection module is used to detect the current output by the current output module to obtain a detection current value, and send the detection current value to the control module;

[0016] The control module is also used to check whether the detected current value is within a preset current range.

[0017] Optionally, the control module is further configured to send the control instruction to the digital-to-analog conversion module to adjust the DAC voltage output by the digital-to-analog conversion module when the detection current value is outside a preset current range.

[0018] Optionally, the control module is further configured to send the control instruction to the digital-to-analog conversion module according to a host computer instruction sent by a host computer.

[0019] Optionally, the control module is implemented using a CPLD (Complex Programmable Logic Device) chip.

[0020] Optionally, the current output module includes: a first resistor, a second resistor, a third resistor, a fourth resistor, an operational amplifier and a MOS (metal oxide semiconductor) tube;

[0021] The first end of the first resistor is connected to the DAC voltage, the second end of the first resistor is electrically connected to the first end of the second resistor and the non-inverting input end of the operational amplifier, and the inverting input end of the operational amplifier is electrically connected to the first end of the fourth resistor and the source of the MOS tube;

[0022] The output end of the operational amplifier is electrically connected to the first end of the third resistor, and the second end of the third resistor is electrically connected to the gate of the MOS tube;

[0023] The second end of the second resistor and the second end of the fourth resistor are both grounded;

[0024] The drain of the MOS tube is used as the current output positive terminal, and the second end of the fourth resistor is used as the current output negative terminal.

[0025] Optionally, different current output ranges are achieved by adjusting the resistance values ​​of the first resistor, the second resistor and the fourth resistor;

[0026] And / or, the MOS tube is an NMOS (N-channel metal oxide semiconductor) tube.

[0027] Optionally, the current output module adopts a current loop transmitter.

[0028] Optionally, the control instruction controls a register inside the digital-to-analog conversion module to output a DAC voltage of an analog quantity corresponding to a voltage value indicated by the control instruction with reference to a reference voltage.

[0029] Optionally, the current detection module includes a sampling resistor;

[0030] The sampling resistor is arranged in the current output loop of the current output module;

[0031] The current detection module is also used to convert the detection current value according to the voltage across the sampling resistor.

[0032] The present disclosure also provides an electronic device, which includes the above-mentioned current output control circuit.

[0033] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present disclosure.

[0034] The positive progressive effect of the present disclosure lies in that all components in the present disclosure are domestic devices, and all are general discrete devices, which can efficiently control the current output, and through the current output loop feedback monitoring, the overall reliability is improved, the damage is reduced, it is beneficial to save costs, and the safety of the system is guaranteed. By replacing and adjusting some components of the current output circuit, different measuring ranges can be set, which increases the scalability and expands the application scenarios of the module. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A module schematic diagram of a current output control circuit provided in Embodiment 1 of the present disclosure;

[0036] Figure 2 A circuit structure diagram of a current output module of a current output control circuit provided in Example 1 of the present disclosure. DETAILED DESCRIPTION

[0037] The present disclosure is further described below by way of examples, but the present disclosure is not limited to the scope of the examples.

[0038] Prefixes such as "first" and "second" are used in the embodiments of the present disclosure only to distinguish different description objects, and have no limiting effect on the position, order, priority, quantity or content of the described objects. The use of prefixes such as ordinal numbers to distinguish description objects in the embodiments of the present disclosure does not constitute a limitation on the described objects. For the statement of the described objects, please refer to the description in the context of the claims or embodiments, and no unnecessary limitation should be constituted due to the use of such prefixes. In addition, in the description of the present embodiment, unless otherwise specified, the meaning of "plurality" is two or more.

[0039] Example 1

[0040] This embodiment provides a current output control circuit. Figure 1 , the current output control circuit includes: a control module 1, a digital-to-analog conversion module 2, a current output module 3 and a current detection module 4;

[0041] The control module 1 is used to send control instructions to the digital-to-analog conversion module 2 .

[0042] The digital-to-analog conversion module 2 is used to output a DAC voltage to the current output module 3 according to a control instruction.

[0043] The current output module 3 is used to output current under the action of the DAC voltage.

[0044] The current detection module 4 is used to detect the current output by the current output module 3 to obtain a detected current value, and send the detected current value to the control module 1 .

[0045] The control module 1 is also used to check whether the detection current value is within a preset current range.

[0046] Among them, analog quantities are usually used to represent various physical quantities, such as voltage, current, temperature, pressure, speed, flow, etc. These physical quantities change continuously in nature, so they need to be represented by analog quantities.

[0047] In signal processing, analog signals refer to signals that change continuously over time. These signals can be audio signals, video signals, sensor signals, etc. The processing of analog signals requires the use of analog circuits and analog electronic devices such as amplifiers, filters, modulators, etc.

[0048] The current output control circuit in this embodiment can control the output of a current signal within a preset current range (e.g., the commonly used 4-20mA), and can monitor the load end current in real time online. This design does not require any components to be replaced after an overload occurs at the load end. The circuit can be restored by re-powering on or re-sending a control command.

[0049] In this embodiment, all components are domestically produced and all are general discrete devices, which can efficiently control the current output. Through the current output loop feedback monitoring, the overall reliability is improved, damage is reduced, cost is saved, and the safety of the system is guaranteed. By replacing and adjusting some components of the current output circuit, different measuring ranges can be set, which increases the scalability and expands the application scenarios of the module.

[0050] In one embodiment, the control module 1 is further configured to send a control instruction to the digital-to-analog conversion module 2 to adjust the DAC voltage output by the digital-to-analog conversion module 2 when the detected current value is outside a preset current range.

[0051] In one embodiment, the control module 1 is further configured to send control instructions to the digital-to-analog conversion module 2 according to the host computer instructions sent by the host computer.

[0052] In one embodiment, the control module 1 is implemented using a CPLD chip.

[0053] In one embodiment, referring to Figure 2 The current output module 3 includes: a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, an operational amplifier U1 and a MOS tube Q1.

[0054] The first end of the first resistor R1 is connected to the DAC voltage, the second end of the first resistor R1 is electrically connected to the first end of the second resistor R2 and the non-inverting input end of the operational amplifier U1, and the inverting input end of the operational amplifier U1 is electrically connected to the first end of the fourth resistor R4 and the source of the MOS tube Q1.

[0055] The output end of the operational amplifier U1 is electrically connected to the first end of the third resistor R3 , and the second end of the third resistor R3 is electrically connected to the gate of the MOS transistor Q1 .

[0056] A second end of the second resistor R2 and a second end of the fourth resistor R4 are both grounded.

[0057] The drain of the MOS tube Q1 is used as a current output positive terminal, and the second end of the fourth resistor R4 is used as a current output negative terminal.

[0058] Among them, after the DAC voltage is input into the current output module 3, it is divided by the first resistor R1 and the second resistor R2 as the positive phase (positive end) input of the operational amplifier U1, and the loop current of the current output loop passes through the fourth resistor R4 to generate voltage feedback as the negative phase (negative end) input of the operational amplifier U1. By utilizing the characteristics of the operational amplifier, the positive phase (positive end) and negative phase (negative end) voltages of the operational amplifier are equal, and the output of the operational amplifier U1 controls the MOS tube Q1 after passing through R3, thereby realizing current output control.

[0059] The current output by the current output module 3 is the loop current in the current output loop.

[0060] The current output module 3 is constructed by combining discrete components, and the overall cost is lower than that of the current loop transmitter.

[0061] In one embodiment, different current output ranges are achieved by adjusting the resistance values ​​of the first resistor R1 , the second resistor R2 , and the fourth resistor R4 .

[0062] Among them, the current output by the current output module 3 = the detection current value, based on the following formula: R4*detection current value=DAC voltage*R2 / (R1+R2).

[0063] When the resistance values ​​of the first resistor R1 , the second resistor R2 and the fourth resistor R4 are set, the current output range can be controlled to be 4-20 mA by setting the output range of the DAC voltage.

[0064] Similarly, when setting the output range of the DAC voltage, different current output ranges can be achieved by adjusting the resistance values ​​of the first resistor R1 , the second resistor R2 , and the fourth resistor R4 .

[0065] In one embodiment, the MOS transistor Q1 is an NMOS transistor.

[0066] In one embodiment, the current output module 3 is a current loop transmitter.

[0067] In one embodiment, the control instruction controls the register inside the digital-to-analog conversion module 2 to output a DAC voltage of an analog quantity corresponding to the voltage value indicated by the control instruction, with the reference voltage as a reference.

[0068] Among them, the implementation of the digital-to-analog conversion module is a prior art and can adopt existing devices, which will not be described in detail here.

[0069] In one embodiment, the current detection module 4 includes a sampling resistor.

[0070] The sampling resistor is arranged in the current output loop in the current output module 3 .

[0071] The current detection module 4 is also used to convert the detection current value according to the voltage across the sampling resistor.

[0072] The current output by the current output module 3 is the loop current in the current output loop, and the loop current flows through the fourth resistor R4. When there is current in the current output loop, a voltage will be generated across the sampling resistor, and the loop current (i.e., the detection current value) will be calculated based on the voltage across the sampling resistor.

[0073] The control module 1 detects whether the current output circuit is normal, that is, whether the output current is normal, by checking whether the detection current value is within the preset current range according to the preset current range set by the host computer.

[0074] Example 2

[0075] This embodiment provides an electronic device, and the electronic device includes the current output control circuit in Embodiment 1.

[0076] In this embodiment, all components of the current output control circuit are domestic devices, and all are general discrete devices, which can efficiently control the current output. Through the current output loop feedback monitoring, the overall reliability is improved, the damage is reduced, it is beneficial to save costs, and the safety of the system is guaranteed. By replacing and adjusting some components of the current output circuit, different measuring ranges can be set, which increases the scalability and expands the application scenarios of the module.

[0077] Although the specific embodiments of the present disclosure are described above, those skilled in the art should understand that this is only an example, and the protection scope of the present disclosure is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present disclosure, but these changes and modifications all fall within the protection scope of the present disclosure.

Claims

1. A current output control circuit, characterized in that: The current output control circuit comprises: a control module, a digital-to-analog conversion module, a current output module and a current detection module; The control module is used to send control instructions to the digital-to-analog conversion module; The digital-to-analog conversion module is used to output a DAC voltage to the current output module according to the control instruction; The current output module is used to output current under the action of the DAC voltage; The current detection module is used to detect the current output by the current output module to obtain a detection current value, and send the detection current value to the control module; The control module is also used to check whether the detected current value is within a preset current range.

2. The current output control circuit according to claim 1, characterized in that: The control module is further configured to send the control instruction to the digital-to-analog conversion module to adjust the DAC voltage output by the digital-to-analog conversion module when the detection current value is outside a preset current range.

3. The current output control circuit according to claim 1, characterized in that: The control module is also used to send the control instruction to the digital-to-analog conversion module according to the host computer instruction sent by the host computer.

4. The current output control circuit according to claim 1, characterized in that: The control module is implemented by using a CPLD chip.

5. The current output control circuit according to claim 1, characterized in that: The current output module includes: a first resistor, a second resistor, a third resistor, a fourth resistor, an operational amplifier and a MOS tube; The first end of the first resistor is connected to the DAC voltage, the second end of the first resistor is electrically connected to the first end of the second resistor and the non-inverting input end of the operational amplifier, and the inverting input end of the operational amplifier is electrically connected to the first end of the fourth resistor and the source of the MOS tube; The output end of the operational amplifier is electrically connected to the first end of the third resistor, and the second end of the third resistor is electrically connected to the gate of the MOS tube; The second end of the second resistor and the second end of the fourth resistor are both grounded; The drain of the MOS tube is used as the current output positive terminal, and the second end of the fourth resistor is used as the current output negative terminal.

6. The current output control circuit according to claim 5, characterized in that: By adjusting the resistance values ​​of the first resistor, the second resistor and the fourth resistor, different current output ranges are achieved; And / or, the MOS tube is an NMOS tube.

7. The current output control circuit according to claim 1, characterized in that: The current output module adopts a current loop transmitter.

8. The current output control circuit according to claim 1, characterized in that: The control instruction controls the register inside the digital-to-analog conversion module to output a DAC voltage of an analog quantity corresponding to a voltage value indicated by the control instruction, with reference to a reference voltage.

9. The current output control circuit according to claim 1, characterized in that: The current detection module includes a sampling resistor; The sampling resistor is arranged in the current output loop of the current output module; The current detection module is also used to convert the detection current value according to the voltage across the sampling resistor.

10. An electronic device, characterized in that: The electronic device comprises the current output control circuit according to any one of claims 1 to 9.

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