A constant current output circuit dynamically adjusts voltage

Abstract

The application relates to the technical field of constant-current output control, and discloses a constant-current output circuit capable of dynamically adjusting voltage, which comprises a dynamic voltage regulating module, a constant-current output module, a detection module and a control module, wherein the dynamic voltage regulating module is used for regulating the power supply voltage output to the constant-current output module based on a control signal output by the control module; the constant-current output module is used for outputting stable direct-current based on a set current signal output by the control module; the detection module is used for sampling the output current and output voltage of the constant-current output module and then sending corresponding current detection signals and voltage detection signals to the control module; and the control module is used for calculating the lowest power supply voltage required for maintaining the current direct-current output and then controlling the dynamic voltage regulating module to output the lowest power supply voltage. The application dynamically adjusts the power supply voltage, so that the power supply voltage of the constant-current output module always follows the load change, the useless voltage drop and power consumption on the power tube are significantly reduced, and the heat generation is reduced.

Description

Technical Field

[0001] This invention relates to the field of constant current output control technology, and more specifically to a constant current output circuit with dynamically adjustable voltage. Background Technology

[0002] Currently, the 4~20mA output circuits widely used in industrial instruments mostly employ linear constant current schemes. Their power supply terminals are typically directly connected to a fixed 24V power supply, causing the linear regulating transistor to bear the entire residual voltage drop between the supply voltage and the loop load voltage. When the load resistance is small or the output current is large, the unwanted voltage difference across the regulating transistor increases significantly, leading to increased unwanted power consumption and severe heat generation. This not only reduces circuit efficiency but also affects the long-term stability of the instrument. The heat generation problem is particularly prominent in low-power instruments and high-temperature environments, limiting the reliability of the instrument in compact spaces or intrinsically safe explosion-proof scenarios. Summary of the Invention

[0003] In view of this, the present invention provides a constant current output circuit with dynamic voltage adjustment to solve the problems of high useless power consumption and severe heat generation of the linear regulating tube under the fixed voltage power supply method in the prior art.

[0004] This invention provides a dynamic voltage-adjustable constant current output circuit, comprising: a dynamic voltage adjustment module, a constant current output module, a detection module, and a control module. The dynamic voltage adjustment module has its input terminal connected to an external power supply, its output terminal connected to the power supply terminal of the constant current output module, and its control terminal connected to the first output terminal of the control module. The dynamic voltage adjustment module is used to adjust the supply voltage output to the constant current output module based on the control signal output by the control module. The constant current output module has its input terminal connected to the second output terminal of the control module and its output terminal connected to the input terminal of the detection module. The constant current output module is used to output a stable DC current based on a set current signal output by the control module. The detection module has its first and second output terminals connected to the first and second input terminals of the control module, respectively. The detection module is used to sample the output current and output voltage of the constant current output module and send the corresponding current detection signal and voltage detection signal to the control module. The control module is used to calculate the minimum supply voltage required to maintain the current DC current output based on the current detection signal and voltage detection signal, and then control the dynamic voltage adjustment module to output the minimum supply voltage.

[0005] The dynamic voltage-adjustable constant current output circuit provided by this invention calculates the minimum supply voltage required to maintain the current DC current output based on the output current and output voltage sampled in real time by the detection module, and controls the dynamic voltage adjustment module to output this minimum supply voltage, achieving real-time tracking of the supply voltage in response to load changes. Compared to traditional fixed voltage supply schemes, this invention automatically reduces the supply voltage when the load decreases or the output current is small, effectively compressing the useless voltage drop on the power transistor, significantly reducing circuit power consumption and heat generation, and improving power efficiency; when the load increases, it automatically raises the supply voltage to ensure that the constant current output is not affected, thus meeting the dual requirements of low power consumption and high-precision constant current output. At the same time, the reduction in power consumption directly alleviates the pressure of device temperature rise, improving the long-term stability and reliability of the circuit in high-temperature environments.

[0006] In one optional embodiment, the dynamic voltage regulation module includes: a voltage divider unit, a voltage conversion unit, and a filtering unit. The first terminal of the voltage divider unit is connected to the first output terminal of the control module, the second terminal of the voltage divider unit is grounded, the third terminal of the voltage divider unit is connected to the first terminal of the filtering unit and the power supply terminal of the constant current output module, and the fourth terminal of the voltage divider unit is connected to the control terminal of the voltage conversion unit. The voltage divider unit is used to divide the control signal output by the control module. The input terminal of the voltage conversion unit is connected to an external power supply, and the output terminal of the voltage conversion unit is connected to the second terminal of the filtering unit. The voltage conversion unit is used to convert the external power supply into a corresponding supply voltage based on the voltage divider signal output by the voltage divider unit. The filtering unit is used to filter the supply voltage.

[0007] In one optional embodiment, the constant current output module includes: a signal conversion unit, a constant current control unit, and a current amplification output unit. The first input terminal of the signal conversion unit is connected to the second output terminal of the control module, the output terminal of the signal conversion unit is connected to the control terminal of the constant current control unit, and the second input terminal of the signal conversion unit is connected to the feedback terminal of the constant current control unit. The signal conversion unit is used to convert the set signal output by the control module into a DC set voltage. The power supply terminal of the constant current control unit is connected to the output terminal of the dynamic voltage regulation module, and the output terminal of the constant current control unit is connected to the input terminal of the current amplification output unit. The constant current control unit is used to generate a constant current drive signal based on the DC set voltage. The input terminal of the current amplification output unit is connected to the output terminal of the dynamic voltage regulation module, and the output terminal of the current amplification output unit is connected to the input terminal of the detection module. The current amplification output unit is used to amplify the current based on the constant current drive signal and output a stable DC current.

[0008] In one optional embodiment, the signal conversion unit includes: an AND gate, a first resistor, a second resistor, a twelfth resistor, a first capacitor, a second capacitor, and a first operational amplifier. The input terminal of the AND gate is connected to the second output terminal of the control module, and the output terminal of the AND gate is connected to the first terminal of the first resistor. The second terminal of the first resistor is connected to the first terminal of the second resistor and grounded through the first capacitor. The second terminal of the second resistor is connected to the non-inverting input terminal of the first operational amplifier and grounded through the second capacitor. The inverting input terminal of the first operational amplifier is connected to the feedback terminal of the constant current control unit through the twelfth resistor, and the output terminal of the first operational amplifier is connected to the control terminal of the constant current control unit.

[0009] In one optional embodiment, the constant current control unit includes: a third resistor, a fourth resistor, a fifth resistor, and a first switch, wherein the first end of the third resistor is connected to the output end of the signal conversion unit, and the second end of the third resistor is connected to the control end of the first switch; the first end of the first switch is connected to the first end of the fourth resistor and the input end of the current amplification output unit, and the second end of the first switch is connected to the first end of the fifth resistor and the second input end of the signal conversion unit; the second end of the fourth resistor is connected to the output end of the dynamic voltage regulation module; and the second end of the fifth resistor is grounded.

[0010] In one optional embodiment, the current amplification output unit includes: an amplifier circuit and a current amplification circuit, wherein the first input terminal of the amplifier circuit is connected to the output terminal of the constant current control unit, the second input terminal of the amplifier circuit is connected to the first terminal of the current amplification circuit, and the output terminal of the amplifier circuit is connected to the control terminal of the current amplification circuit. The amplifier circuit is used to amplify the constant current drive signal. The power supply terminal of the current amplification circuit is connected to the output terminal of the dynamic voltage regulation module, and the output terminal of the current amplification circuit is connected to the input terminal of the detection module. The current amplification circuit is used to amplify the current based on the amplified constant current drive signal.

[0011] In one optional embodiment, the current amplification circuit includes: a sixth resistor, a seventh resistor, a second switch, and a third switch, wherein the first end of the sixth resistor is connected to the output terminal of the amplifier circuit, and the second end of the sixth resistor is connected to the control terminal of the second switch; the first end of the second switch is connected to the first end of the third switch, the first end of the seventh resistor, and the second input terminal of the amplifier circuit, and the second end of the second switch is connected to the control terminal of the third switch; the second end of the third switch is connected to the input terminal of the detection module; and the second end of the seventh resistor is connected to the output terminal of the dynamic voltage regulation module.

[0012] In one optional embodiment, the detection module includes: a sampling unit, a buffer unit, and a differential amplifier unit. The first terminal of the sampling unit is connected to the output terminal of the constant current output module, and its second terminal outputs a stable DC current. The first input terminal of the buffer unit is connected to the first terminal of the sampling unit, the second input terminal of the buffer unit is connected to the second terminal of the sampling unit, the first output terminal of the buffer unit is connected to the first input terminal of the differential amplifier unit, and the second output terminal of the buffer unit is connected to the second input terminal of the differential amplifier unit, outputting a voltage detection signal. The buffer unit is used to buffer and isolate the potentials across the sampling unit. The output terminal of the differential amplifier unit outputs a current detection signal, amplifying the voltage difference across the sampling unit before outputting it.

[0013] In one optional embodiment, the buffer unit includes a second operational amplifier and a third operational amplifier, wherein the non-inverting input of the second operational amplifier is connected to the first terminal of the sampling unit, and the output of the second operational amplifier is connected to the inverting input of the second operational amplifier and the first input of the differential amplifier; the non-inverting input of the third operational amplifier is connected to the second terminal of the sampling unit, and the output of the third operational amplifier is connected to the inverting input of the third operational amplifier and the second input of the differential amplifier; the output of the third operational amplifier also outputs a voltage detection signal.

[0014] In one optional embodiment, the differential amplifier unit includes: an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, and a fourth operational amplifier, wherein the first terminal of the eighth resistor is grounded, and the second terminal of the eighth resistor is connected to the first terminal of the ninth resistor and the non-inverting input terminal of the fourth operational amplifier; the second terminal of the ninth resistor is connected to the first output terminal of the buffer unit; the first terminal of the tenth resistor is connected to the inverting input terminal of the fourth operational amplifier and the first terminal of the eleventh resistor, and the second terminal of the tenth resistor is connected to the second output terminal of the buffer unit; the second terminal of the eleventh resistor is connected to the output terminal of the fourth operational amplifier; the output terminal of the fourth operational amplifier also outputs a current detection signal. Attached Figure Description

[0015] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of a constant current output circuit for dynamically adjustable voltage according to an embodiment of the present invention; Figure 2This is a detailed circuit diagram of the dynamic voltage regulation module according to an embodiment of the present invention; Figure 3 This is a specific circuit diagram of a constant current output circuit for dynamically adjusting voltage according to an embodiment of the present invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0019] In this invention, terms such as "connection," "linked," "connected," and "joined" that indicate electrical connection, unless otherwise specified, refer to direct or indirect electrical connections. A direct electrical connection refers to a direct connection between two or more objects without any intervening objects, while an indirect electrical connection refers to a connection between two or more objects with one or more intervening objects (such as electrical components or units like resistors, capacitors, inductors, switches, and filters).

[0020] In the field of industrial automation control, the 4~20mA analog signal transmission standard has become the main method for signal transmission between field instruments such as transmitters and actuators and control systems due to its strong anti-interference ability, long transmission distance, and disconnection detection capability. In this standard, 4mA represents the lower limit of the range (including the equipment operating current), and 20mA represents the upper limit of the range. The magnitude of the loop current linearly reflects the measured physical quantity, and its accuracy directly determines the accuracy and reliability of industrial process control. However, precisely because it is a precision analog signal transmission standard, it has extremely high requirements for the accuracy and stability of the output current. While traditional fixed voltage power supply schemes can guarantee accuracy requirements, they sacrifice power consumption. Therefore, this embodiment specifically optimizes the 4~20mA current output standard for low power consumption, achieving dynamic adjustment of the power supply voltage while ensuring the required current output accuracy of the standard, thus solving the problems of high power consumption and severe heat generation.

[0021] This embodiment provides a constant current output circuit with dynamically adjustable voltage, such as... Figure 1As shown, it includes: dynamic voltage regulation module 1, constant current output module 2, detection module 3 and control module 4.

[0022] Figure 1 In the middle, the dynamic voltage regulating module 1 has its input terminal connected to an external power supply, its output terminal connected to the power supply terminal of the constant current output module 2, and its control terminal connected to the first output terminal of the control module 4.

[0023] Specifically, Figure 1 In this module, the dynamic voltage regulation module 1 is used to adjust the supply voltage V_ADJ of the constant current output module 2 in real time based on the control signal MCU_DAC output by the control module 4. This allows the supply voltage V_ADJ to dynamically change according to the load (connected to the IOut terminal). Under light load or low current output, the supply voltage V_ADJ is automatically reduced, and under heavy load or high current output, the supply voltage V_ADJ is automatically increased. This enables the supply voltage V_ADJ to follow the load changes in real time, fundamentally reducing the useless voltage drop on the power transistor in the constant current output module 2, reducing the heat generation on the power transistor, and achieving low power consumption operation.

[0024] Figure 1 In the middle, the constant current output module 2 has its input terminal connected to the second output terminal of the control module 4, and its output terminal connected to the input terminal of the detection module 3.

[0025] Specifically, Figure 1 In the middle, the constant current output module 2 is used to control the output of a stable DC current IOut corresponding to the set value based on the set current signal MCU_PWM output by the control module 4 through internal closed-loop feedback. When the load changes and the output current fluctuates, the conduction degree is automatically adjusted to restore to the set value, ensuring that the high-precision constant current output characteristics can be maintained under different load conditions and supply voltages, and guaranteeing the stability and accuracy of the 4~20mA loop current.

[0026] Figure 1 In the middle, the detection module 3 has its first output terminal and second output terminal connected to the first input terminal and second input terminal of the control module 4, respectively.

[0027] Specifically, Figure 1 In the middle, the detection module 3 is used to sample the output current and output voltage of the constant current output module 2 in real time. It is connected to the output circuit in a high impedance buffer isolation manner, and hardly draws current from the current loop, so as to avoid the sampling process affecting the accuracy of the output current. At the same time, the weak differential voltage signal obtained by sampling is differentially amplified and output as the current detection signal Current_FB, and the load side potential is directly output as the voltage detection signal Voltage_FB, providing the control module 4 with accurate loop current and load voltage information, as the data basis for dynamic voltage regulation decision.

[0028] Figure 1 In the middle, the control module 4 is used to calculate the minimum supply voltage required to maintain the current DC current output based on the current detection signal Current_FB and the voltage detection signal Voltage_FB, and then control the dynamic voltage regulation module 1 to output the minimum supply voltage.

[0029] Specifically, Figure 1 In this system, control module 4 calculates the loop current based on the received current detection signal Current_FB, obtains the load voltage based on the voltage detection signal Voltage_FB, and calculates the minimum supply voltage required to maintain the current DC current output based on the loop current and load voltage. Then, it outputs a corresponding control signal MCU_DAC to the dynamic voltage regulation module 1 through its first output terminal, controlling the dynamic voltage regulation module 1 to adjust the supply voltage V_ADJ to this minimum supply voltage. This control process is a real-time closed-loop control. Control module 4 continuously monitors the loop status and dynamically adjusts the supply voltage V_ADJ, ensuring that V_ADJ is always maintained at the minimum level required for constant current output. This guarantees that the 4~20mA current output accuracy is not affected, while minimizing useless power consumption and heat generation on the power transistor, achieving a balance between high-precision constant current output and low-power operation.

[0030] The dynamic voltage-adjustable constant current output circuit provided in this embodiment calculates the minimum supply voltage required to maintain the current DC current output based on the output current and output voltage sampled in real time by the detection module, and controls the dynamic voltage adjustment module to output this minimum supply voltage, achieving real-time tracking of the supply voltage in response to load changes. Compared to traditional fixed voltage supply schemes, this invention automatically reduces the supply voltage when the load decreases or the output current is small, effectively compressing the useless voltage drop on the power transistor, significantly reducing circuit power consumption and heat generation, and improving power efficiency; when the load increases, it automatically raises the supply voltage to ensure that the constant current output is not affected, thus meeting the dual requirements of low power consumption and high-precision constant current output. At the same time, the reduction in power consumption directly alleviates the pressure of device temperature rise, improving the long-term stability and reliability of the circuit in high-temperature environments.

[0031] In some alternative implementations, such as Figure 1As shown, the dynamic voltage regulation module 1 includes a voltage divider unit 11, a voltage conversion unit 12, and a filter unit 13. The first terminal of the voltage divider unit 11 is connected to the first output terminal of the control module 4, the second terminal of the voltage divider unit 11 is grounded, the third terminal of the voltage divider unit 11 is connected to the first terminal of the filter unit 13 and the power supply terminal of the constant current output module 2, and the fourth terminal of the voltage divider unit 11 is connected to the control terminal of the voltage conversion unit 12. The voltage divider unit 11 is used to divide the control signal MCU_DAC output by the control module 4. The input terminal of the voltage conversion unit 12 is connected to an external power supply, and the output terminal of the voltage conversion unit 12 is connected to the second terminal of the filter unit 13. The voltage conversion unit 12 is used to convert the external power supply into a corresponding supply voltage V_ADJ based on the voltage divider signal output by the voltage divider unit 11. The filter unit 13 is used to filter the supply voltage V_ADJ.

[0032] Specifically, Figure 1 In this circuit, control module 4 calculates the minimum required supply voltage based on the current detection signal Current_FB and the voltage detection signal Voltage_FB. Then, it outputs a control signal MCU_DAC corresponding to the voltage value to voltage divider unit 11 via its first output terminal. This control signal is processed by voltage divider unit 11 and sent to the control terminal of voltage conversion unit 12 to change the potential of the feedback node inside voltage conversion unit 12, thus changing its output voltage accordingly. The input terminal of voltage conversion unit 12 is connected to an external power supply to convert a higher external DC voltage into an adjustable supply voltage V_ADJ. Its output voltage value corresponds to the voltage divider signal received by the control terminal. When the control signal MCU_DAC changes, the supply voltage V_ADJ rises and falls synchronously, achieving programmed adjustment of the supply voltage. Voltage divider unit 11 also simultaneously feeds back the output supply voltage V_ADJ to the control terminal of voltage conversion unit 12, forming a closed-loop voltage regulation network to ensure that the output voltage remains stable at the set value. The filter unit 13 is connected to the output terminal of the voltage conversion unit 12 and is used to filter and smooth the power supply voltage V_ADJ to provide a stable, low-ripple DC power supply for the constant current output module 2.

[0033] Specifically, Figure 2 In the process, voltage divider unit 11 includes resistors R97, R102, and R104; voltage conversion unit 12 includes voltage conversion chip U26, resistor R101, and capacitors C71, C72, and C80; and filter unit 13 includes inductor L3 and capacitors C81 and C24.

[0034] In some alternative implementations, such as Figure 1As shown, the constant current output module 2 includes: a signal conversion unit 21, a constant current control unit 22, and a current amplification output unit 23. The first input terminal of the signal conversion unit 21 is connected to the second output terminal of the control module 4, the output terminal of the signal conversion unit 21 is connected to the control terminal of the constant current control unit 22, and the second input terminal of the signal conversion unit 21 is connected to the feedback terminal of the constant current control unit 22. The signal conversion unit 21 is used to convert the set signal output by the control module 4 into a DC set voltage. The power supply terminal of the constant current control unit 22 is connected to the output terminal of the dynamic voltage regulation module 1, and the output terminal of the constant current control unit 22 is connected to the input terminal of the current amplification output unit 23. The constant current control unit 22 is used to generate a constant current drive signal based on the DC set voltage. The input terminal of the current amplification output unit 23 is connected to the output terminal of the dynamic voltage regulation module 1, and the output terminal of the current amplification output unit 23 is connected to the input terminal of the detection module 3. The current amplification output unit 23 is used to amplify the current based on the constant current drive signal and output a stable DC current.

[0035] Specifically, Figure 1 In the control module 4, the set current signal MCU_PWM (such as a PWM pulse signal) output is filtered and smoothed by the signal conversion unit 21, and then converted into a smooth DC set voltage, which is sent to the constant current control unit 22 as the reference value for current output. The constant current control unit 22 compares this DC set voltage with the feedback signal of the output loop. When the feedback signal deviates from the set value, the constant current control unit 22 automatically adjusts its output drive signal so that the output current always follows the change of the set value. Under the control of the drive signal, the current amplification output unit 23 amplifies the power supply current provided by the dynamic voltage regulation module 1 and outputs it to meet the high current output requirements under different load conditions in the 4~20mA loop. When the load change causes the output current to fluctuate, the constant current control unit 22 detects the change of output current in real time through the feedback terminal. Its internal negative feedback loop automatically adjusts the amplitude of the drive signal, so that the conduction degree of the current amplification output unit 23 changes accordingly, and the output current is quickly restored to the set value, forming a closed-loop constant current control. Since the power supply voltage V_ADJ of the current amplification output unit 23 is adjusted in real time by the dynamic voltage regulation module 1 according to the current load conditions, the voltage drop across the current amplification output unit 23 is always maintained at the minimum required operating level, thereby minimizing the useless power consumption and heat generation on the current amplification output unit 23 while ensuring constant current accuracy.

[0036] Specifically, Figure 3In the signal conversion unit 21, there are: AND gate U32, first resistor R115, second resistor R116, twelfth resistor R122, first capacitor C86, second capacitor C87, and first operational amplifier U33B. The input terminal of AND gate U32 is connected to the second output terminal of control module 4, and the output terminal of AND gate U32 is connected to the first terminal of first resistor R115. The second terminal of first resistor R115 is connected to the first terminal of second resistor R116 and grounded through first capacitor C86. The second terminal of second resistor R116 is connected to the non-inverting input terminal of first operational amplifier U33B and grounded through second capacitor C87. The inverting input terminal of first operational amplifier U33B is connected to the feedback terminal of constant current control unit 22 through twelfth resistor R122, and the output terminal of first operational amplifier U33B is connected to the control terminal of constant current control unit 22.

[0037] Specifically, Figure 3 In the constant current control unit 22, there are: a third resistor R117, a fourth resistor R111, a fifth resistor R123, and a first switch M3. The first end of the third resistor R117 is connected to the output end of the signal conversion unit 21, and the second end of the third resistor R117 is connected to the control end of the first switch M3. The first end of the first switch M3 is connected to the first end of the fourth resistor R111 and the input end of the current amplification output unit 23. The second end of the first switch M3 is connected to the first end of the fifth resistor R123 and the second input end of the signal conversion unit 21. The second end of the fourth resistor R111 is connected to the output end of the dynamic voltage regulation module 1. The second end of the fifth resistor R123 is grounded.

[0038] The DC setting voltage output by signal conversion unit 21 is transmitted to the control terminal of the first switch M3 via the third resistor R117 to control the conduction level of the first switch M3. The first terminal of the first switch M3 is connected to the output terminal V_ADJ of the dynamic voltage regulation module 1 via the fourth resistor R111 to provide it with operating current; the second terminal of the first switch M3 is grounded via the fifth resistor R123, which converts the current flowing through the first switch M3 into a feedback voltage and sends it back to the second input terminal of signal conversion unit 21. When the output current changes due to load changes or supply voltage fluctuations, the current flowing through the fifth resistor R123 changes accordingly, and the feedback voltage on it changes accordingly. Signal conversion unit 21 adjusts its output DC setting voltage according to the feedback voltage, causing the conduction level of the first switch M3 to change in the opposite direction to offset the output current deviation, quickly restoring the output current to the set value, forming a closed-loop constant current control. The fourth resistor R111 is connected between the supply voltage V_ADJ and the first terminal of the first switch M3 to provide a bias voltage for the first switch M3 and limit its operating current. Therefore, the constant current control unit 22 controls the output current of the subsequent current amplification output unit 23 by controlling the conduction degree of the first switch M3, so that it is always equal to the set value, ensuring that high-precision constant current output can be maintained under different load and power supply voltage conditions.

[0039] Specifically, Figure 3 In the above, the current amplification output unit 23 includes an amplifier circuit 231 and a current amplification circuit 232. The first input terminal of the amplifier circuit 231 is connected to the output terminal of the constant current control unit 22, the second input terminal of the amplifier circuit 231 is connected to the first terminal of the current amplification circuit 232, and the output terminal of the amplifier circuit 231 is connected to the control terminal of the current amplification circuit 232. The amplifier circuit 231 is used to amplify the constant current drive signal. The power supply terminal of the current amplification circuit 232 is connected to the output terminal of the dynamic voltage regulation module 1, and the output terminal of the current amplification circuit 232 is connected to the input terminal of the detection module 3. The current amplification circuit 232 is used to amplify the current based on the amplified constant current drive signal.

[0040] Specifically, Figure 3In the above circuit, amplifier circuit 231 includes: operational amplifier U33A, resistor R120, resistor R114 and capacitor C91; current amplification circuit 232 includes: sixth resistor R118, seventh resistor R98, second switch Q4 and third switch Q16, wherein the first end of the sixth resistor R118 is connected to the output terminal of amplifier circuit 231, and the second end of the sixth resistor R118 is connected to the control terminal of second switch Q4; the first end of the second switch Q4 is connected to the first end of third switch Q16, the first end of seventh resistor R98 and the second input terminal of amplifier circuit 231, and the second end of second switch Q4 is connected to the control terminal of third switch Q16; the second end of third switch Q16 is connected to the input terminal of detection module 3; the second end of seventh resistor R98 is connected to the output terminal (i.e. V_ADJ) of dynamic voltage regulation module 1. The drive signal output by amplifier circuit 231 is transmitted to the control terminal of second switch Q4 via the sixth resistor R188. Second switch Q4 and third switch Q16 form a composite amplifier structure. Second switch Q4 pre-amplifies the drive signal and directly drives third switch Q16. Third switch Q16 then amplifies the current and outputs it to detection module 3. The seventh resistor R98 introduces the supply voltage V_ADJ into the feedback node of the composite amplifier structure, allowing changes in the output current to be reflected in real time at the feedback terminal of amplifier circuit 231. Amplifier circuit 231 automatically adjusts the amplitude of its output drive signal based on the feedback signal, ensuring that the output current always follows the set value, thus ensuring that the current amplification circuit 232 can still output a high-precision, stable DC current under dynamic voltage regulation power supply conditions.

[0041] In some alternative implementations, such as Figure 1 As shown, the detection module 3 includes a sampling unit 31, a buffer unit 32, and a differential amplifier unit 33. The first end of the sampling unit 31 is connected to the output end of the constant current output module 2, and its second end outputs a stable DC current. The first input end of the buffer unit 32 is connected to the first end of the sampling unit 31, the second input end of the buffer unit 32 is connected to the second end of the sampling unit 31, the first output end of the buffer unit 32 is connected to the first input end of the differential amplifier unit 33, and the second output end of the buffer unit 32 is connected to the second input end of the differential amplifier unit 33, and outputs a voltage detection signal Voltage_FB. The buffer unit 32 is used to buffer and isolate the potential across the sampling unit 31. The output end of the differential amplifier unit 33 outputs a current detection signal Current_FB, and the differential amplifier unit 33 is used to amplify the voltage difference across the sampling unit 31 before outputting it.

[0042] Specifically, Figure 3In the sample unit, the sampling unit includes a sampling resistor R99, and the buffer unit 32 includes a second operational amplifier U99B and a third operational amplifier U97B. The non-inverting input of the second operational amplifier U99B is connected to the first terminal of the sample unit 31, and the output of the second operational amplifier U99B is connected to the inverting input of the second operational amplifier U99B and the first input terminal (i.e., the right end of R95) of the differential amplifier unit 33. The non-inverting input of the third operational amplifier U97B is connected to the second terminal of the sample unit 31, and the output of the third operational amplifier U97B is connected to the inverting input of the third operational amplifier U97B and the second input terminal (i.e., the right end of R94) of the differential amplifier unit 33. The output of the third operational amplifier U97B also outputs a voltage detection signal Voltage_FB.

[0043] Specifically, Figure 3 In the differential amplifier unit 33, there are: an eighth resistor R96, a ninth resistor R95, a tenth resistor R94, an eleventh resistor R93, and a fourth operational amplifier U98B. The first terminal of the eighth resistor R96 is grounded, and the second terminal of the eighth resistor R96 is connected to the first terminal of the ninth resistor R95 and the non-inverting input terminal of the fourth operational amplifier U98B. The second terminal of the ninth resistor R95 is connected to the first output terminal of the buffer unit 32 (i.e., the output terminal of U99B). The first terminal of the tenth resistor R94 is connected to the inverting input terminal of the fourth operational amplifier U98B and the first terminal of the eleventh resistor R93. The second terminal of the tenth resistor R94 is connected to the second output terminal of the buffer unit 32 (i.e., the output terminal of U97B). The second terminal of the eleventh resistor R93 is connected to the output terminal of the fourth operational amplifier U98B. The output terminal of the fourth operational amplifier U98B also outputs a current detection signal Current_FB.

[0044] Specifically, Figure 3In the sampling module, buffer unit 32 uses two voltage followers to buffer the potential across the sampling resistor R99 with high impedance. Their extremely high input impedance draws almost no current from the current loop, avoiding any impact on the 4~20mA current accuracy during sampling. The buffered potentials are then fed into differential amplifier unit 33 for differential amplification. Differential amplifier unit 33 outputs a voltage signal proportional to the loop current based on the voltage difference across the sampling resistor R99, which is sent to control module 4 as the current detection signal Current_FB. Simultaneously, buffer unit 32 also directly outputs the potential at the second terminal of the sampling resistor R99 as the voltage detection signal Voltage_FB, which is sent to control module 4. This potential represents the true voltage on the load side, excluding the voltage drop across the sampling resistor R99, thus eliminating the measurement offset caused by the current sensing resistor. Therefore, detection module 3 synchronously outputs the current detection signal Current_FB and the voltage detection signal Voltage_FB, enabling control module 4 to simultaneously acquire loop current and load voltage information, providing a complete data foundation for dynamic voltage regulation.

[0045] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A constant current output circuit with dynamically adjustable voltage, characterized in that, include: The system comprises a dynamic voltage regulation module, a constant current output module, a detection module, and a control module. The dynamic voltage regulation module has its input terminal connected to an external power supply, its output terminal connected to the power supply terminal of the constant current output module, and its control terminal connected to the first output terminal of the control module. The dynamic voltage regulation module is used to adjust the power supply voltage output to the constant current output module based on the control signal output by the control module. The constant current output module has its input terminal connected to the second output terminal of the control module and its output terminal connected to the input terminal of the detection module. The constant current output module is used to output a stable DC current based on the set current signal output by the control module. The detection module has its first output terminal and second output terminal connected to the first input terminal and second input terminal of the control module, respectively. The detection module is used to sample the output current and output voltage of the constant current output module and then send the corresponding current detection signal and voltage detection signal to the control module. The control module is used to calculate the minimum supply voltage required to maintain the current DC current output based on the current detection signal and the voltage detection signal, and then control the dynamic voltage regulation module to output the minimum supply voltage.

2. The circuit according to claim 1, characterized in that, The dynamic voltage regulation module includes: a voltage divider unit, a voltage conversion unit, and a filtering unit, wherein... The first terminal of the voltage divider unit is connected to the first output terminal of the control module, the second terminal of the voltage divider unit is grounded, the third terminal of the voltage divider unit is connected to the first terminal of the filter unit and the power supply terminal of the constant current output module, and the fourth terminal of the voltage divider unit is connected to the control terminal of the voltage conversion unit. The voltage divider unit is used to divide the control signal output by the control module. The input terminal of the voltage conversion unit is connected to an external power supply, and the output terminal of the voltage conversion unit is connected to the second terminal of the filter unit. The voltage conversion unit is used to convert the external power supply into a corresponding supply voltage according to the voltage divider signal output by the voltage divider unit. The filtering unit is used to filter the power supply voltage.

3. The circuit according to claim 1, characterized in that, The constant current output module includes: a signal conversion unit, a constant current control unit, and a current amplification output unit, wherein... The first input terminal of the signal conversion unit is connected to the second output terminal of the control module, the output terminal of the signal conversion unit is connected to the control terminal of the constant current control unit, and the second input terminal of the signal conversion unit is connected to the feedback terminal of the constant current control unit. The signal conversion unit is used to convert the set signal output by the control module into a DC set voltage. The power supply terminal of the constant current control unit is connected to the output terminal of the dynamic voltage regulation module, and the output terminal of the constant current control unit is connected to the input terminal of the current amplification output unit. The constant current control unit is used to generate a constant current drive signal according to the DC set voltage. The input terminal of the current amplification output unit is connected to the output terminal of the dynamic voltage regulation module, and the output terminal of the current amplification output unit is connected to the input terminal of the detection module. The current amplification output unit is used to amplify the current according to the constant current drive signal and output a stable DC current.

4. The circuit according to claim 3, characterized in that, The signal conversion unit includes: an AND gate, a first resistor, a second resistor, a twelfth resistor, a first capacitor, a second capacitor, and a first operational amplifier, wherein... The input terminal of the AND gate is connected to the second output terminal of the control module, and the output terminal of the AND gate is connected to the first terminal of the first resistor; The second end of the first resistor is connected to the first end of the second resistor, and is grounded through the first capacitor; The second end of the second resistor is connected to the non-inverting input of the first operational amplifier and is grounded through the second capacitor; The inverting input terminal of the first operational amplifier is connected to the feedback terminal of the constant current control unit through the twelfth resistor, and the output terminal of the first operational amplifier is connected to the control terminal of the constant current control unit.

5. The circuit according to claim 3, characterized in that, The constant current control unit includes: a third resistor, a fourth resistor, a fifth resistor, and a first switch, wherein, The first end of the third resistor is connected to the output end of the signal conversion unit, and the second end of the third resistor is connected to the control end of the first switch. The first terminal of the first switch is connected to the first terminal of the fourth resistor and the input terminal of the current amplification output unit, and the second terminal of the first switch is connected to the first terminal of the fifth resistor and the second input terminal of the signal conversion unit. The second end of the fourth resistor is connected to the output end of the dynamic voltage regulation module; The second terminal of the fifth resistor is grounded.

6. The circuit according to claim 3, characterized in that, The current-amplifying output unit includes: an amplifier circuit and a current-amplifying circuit, wherein... The first input terminal of the amplifier circuit is connected to the output terminal of the constant current control unit, the second input terminal of the amplifier circuit is connected to the first terminal of the current amplification circuit, and the output terminal of the amplifier circuit is connected to the control terminal of the current amplification circuit. The amplifier circuit is used to amplify the constant current drive signal. The power supply terminal of the current amplification circuit is connected to the output terminal of the dynamic voltage regulation module, and the output terminal of the current amplification circuit is connected to the input terminal of the detection module. The current amplification circuit is used to amplify the current based on the amplified constant current drive signal.

7. The circuit according to claim 6, characterized in that, The current-amplifying circuit includes: a sixth resistor, a seventh resistor, a second switch, and a third switch, wherein, The first end of the sixth resistor is connected to the output end of the amplifier circuit, and the second end of the sixth resistor is connected to the control end of the second switch. The first terminal of the second switch is connected to the first terminal of the third switch, the first terminal of the seventh resistor, and the second input terminal of the amplifier circuit; the second terminal of the second switch is connected to the control terminal of the third switch. The second terminal of the third switch is connected to the input terminal of the detection module; The second end of the seventh resistor is connected to the output end of the dynamic voltage regulation module.

8. The circuit according to claim 1, characterized in that, The detection module includes: a sampling unit, a buffer unit, and a differential amplification unit, wherein, The first end of the sampling unit is connected to the output end of the constant current output module, and its second end outputs a stable DC current. The first input terminal of the buffer unit is connected to the first terminal of the sampling unit, the second input terminal of the buffer unit is connected to the second terminal of the sampling unit, the first output terminal of the buffer unit is connected to the first input terminal of the differential amplifier unit, the second output terminal of the buffer unit is connected to the second input terminal of the differential amplifier unit, and outputs a voltage detection signal. The buffer unit is used to buffer and isolate the potentials at both ends of the sampling unit. The differential amplifier unit outputs a current detection signal at its output terminal. The differential amplifier unit is used to amplify the voltage difference across the sampling unit and then output it.

9. The circuit according to claim 8, characterized in that, The buffer unit includes a second operational amplifier and a third operational amplifier, wherein... The non-inverting input of the second operational amplifier is connected to the first terminal of the sampling unit, and the output of the second operational amplifier is connected to the inverting input of the second operational amplifier and the first input of the differential amplifier unit. The non-inverting input of the third operational amplifier is connected to the second terminal of the sampling unit, and the output of the third operational amplifier is connected to the inverting input of the third operational amplifier and the second input of the differential amplifier unit. The output of the third operational amplifier also outputs a voltage detection signal.

10. The circuit according to claim 8, characterized in that, The differential amplifier unit includes: an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, and a fourth operational amplifier, wherein, The first terminal of the eighth resistor is grounded, and the second terminal of the eighth resistor is connected to the first terminal of the ninth resistor and the non-inverting input terminal of the fourth operational amplifier. The second end of the ninth resistor is connected to the first output end of the buffer unit; The first end of the tenth resistor is connected to the inverting input terminal of the fourth operational amplifier and the first end of the eleventh resistor, and the second end of the tenth resistor is connected to the second output terminal of the buffer unit. The second terminal of the eleventh resistor is connected to the output terminal of the fourth operational amplifier; The output of the fourth operational amplifier also outputs a current detection signal.

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