High-bandwidth constant current source circuit and device

Abstract

The embodiment of the invention relates to the field of circuit design, in particular to a high-bandwidth constant current source circuit and device.The circuit comprises a man-machine interaction module, a microcontroller module, an adjustable reference voltage module, a direct current source module and an alternating current source module, the microcontroller module is connected with a digital-to-analog converter sub-module in the adjustable reference voltage module, receives a trigger signal through an I / O port, and determines a first output current according to the trigger signal; the microcontroller module is connected with the alternating current source module, the microcontroller module outputs a waveform signal to the alternating current source module, and the direct current source module is used for switching the first output current according to the trigger signal. And the alternating current source module is used for outputting a second output current according to the input waveform signal. The stability of alternating current and direct current is improved.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of circuit design, and in particular to a high-bandwidth constant current source circuit and device. Background Art

[0002] A constant current source is a power supply device that can output a constant current. It is widely used in electronic equipment manufacturing, testing, calibration, automation, and laboratories. Especially in cold atom experiments, the role of constant current sources is particularly critical. It needs to have the characteristics of wide bandwidth, high stability, fast response, fast jump, and long-term stable operation. However, existing commercial constant current sources often have problems such as high noise and low current stability, which makes it difficult to meet the needs of precision experiments. For example, in cold atom experiments, they need to provide a highly stable magnetic field for the experiment; in the fields of nuclear magnetic resonance of medical equipment and precise chemical reactions in electrochemical applications, the stability and accuracy of the current source are extremely high. In addition, many experiments require rapid changes in current, which requires the current source to have a fast jump response and sufficient bandwidth. For example, in different stages of cold atom experiments, magnetic fields of different sizes may be required, and the corresponding current requirements range from milliamperes to several amperes. This requires not only that the current can jump quickly, but sometimes it also needs to be able to switch on and off quickly, which places high demands on the circuit bandwidth.

[0003] Traditional constant current sources mostly use single-channel output. Increasing the bandwidth of the output current often increases noise and affects the stability of the DC output. Most products on the market are mainly single-function and cannot be controlled by external TTL signals. High-precision, high-current constant current sources are expensive, and experiments often require constant current sources with multiple functions, which makes the use of the equipment complicated and increases the cost of use. Summary of the invention

[0004] One purpose of the embodiments of the present application is to provide a high-bandwidth constant current source circuit and device to solve the technical problem that the constant current source cannot be controlled by an external signal.

[0005] In a first aspect, a high-bandwidth constant current source circuit is provided, the circuit comprising: a human-computer interaction module, a microcontroller module, an adjustable reference voltage module, a direct current source module, and an alternating current source module, the microcontroller module being connected to the human-computer interaction module via a serial port, the microcontroller module being connected to a digital-to-analog converter submodule in the adjustable reference voltage module, the microcontroller module receiving a trigger signal via an I / O port, and determining a first output current according to the trigger signal; the microcontroller module being connected to the alternating current source module, the microcontroller module outputting a waveform signal to the alternating current source module, the direct current source module being used to switch the first output current according to the trigger signal, the alternating current source module being used to output a second output current according to the input waveform signal, and outputting the first output current or the second output current in the high-bandwidth constant current source circuit.

[0006] Optionally, the adjustable reference voltage module includes a reference voltage submodule and a digital-to-analog converter submodule, the first output voltage in the reference voltage submodule is connected to the positive reference voltage input terminal in the digital-to-analog converter submodule, the second output voltage in the reference voltage submodule is connected to the negative reference voltage input terminal in the digital-to-analog converter submodule, the three signal connection terminals in the digital-to-analog converter submodule are all connected to the microcontroller module, and the three signal connection terminals transmit data according to the timing of the communication protocol corresponding to the serial peripheral device interface in the microcontroller module; the reference voltage submodule provides a reference voltage for the digital-to-analog converter submodule.

[0007] Optionally, the DC current source module includes an error amplifier submodule, a power amplifier submodule, and a sampling feedback circuit submodule; wherein one end of the error amplifier submodule is connected to one end of the power amplifier submodule, the other end of the error amplifier submodule is connected to one end of the sampling feedback circuit submodule, and the other end of the power amplifier submodule is connected to the other end of the sampling feedback circuit submodule.

[0008] Optionally, the error amplification submodule includes a first resistor, a second resistor, a first capacitor, a second capacitor and a first operational amplifier; wherein, the first end of the first resistor is connected to the digital-to-analog converter submodule in the adjustable reference voltage module, the second end of the first resistor is connected to the reverse end of the first operational amplifier, the first end of the first capacitor is connected to the reverse end of the first operational amplifier, the second end of the first capacitor is connected to the output end of the first operational amplifier, the second resistor is connected in parallel with the second capacitor to obtain a first parallel end and a second parallel end, the first parallel end is connected to the reverse end of the first operational amplifier, the second parallel end is connected to the feedback end of the sampling feedback circuit submodule, and the in-phase end of the first operational amplifier is grounded.

[0009] Optionally, the power amplifier submodule includes a first triode, a second triode, a third triode, a fourth triode, a third resistor, a first bias current source and a second bias current source; wherein the collector of the first triode is connected to a positive power supply, the base of the first triode is connected to the base of the second triode, the emitter of the first triode is connected to a first end of the second bias current source, the second end of the second bias current source is connected to a negative power supply, the third resistor is connected to the base of the first triode and the base of the second triode, and the emitter of the first triode is connected to a first end of the second bias current source, and the second end of the second bias current source is connected to a negative power supply. The collector of the second triode is connected to the negative power supply, the emitter of the second triode is connected to the first end of the first bias current source, the second end of the first bias current source is connected to the positive power supply, the collector of the third triode is connected to the positive power supply, the emitter of the third triode is connected to the collector of the fourth triode, the base of the third triode is connected to the emitter of the second triode, the emitter of the fourth triode is connected to the negative power supply, and the base of the fourth triode is connected to the emitter of the first triode.

[0010] Optionally, the sampling feedback circuit submodule includes a sampling resistor, a second operational amplifier, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor and a load resistor; wherein one end of the sampling resistor is connected to the collector of the fourth triode, one end of the fourth resistor is connected to a first node, the first node is a connection node between one end of the sampling resistor and the collector of the fourth triode, the other two ends of the sampling resistor are connected to one end of the load resistor, the other end of the load resistor is grounded, the other end of the fourth resistor is connected to one end of the fifth resistor, the other end of the fourth resistor is connected to the reverse end of the second operational amplifier, the other end of the fifth resistor is connected to the output end of the second operational amplifier, the output end of the second operational amplifier is a feedback end, the same direction end of the second operational amplifier is connected to one end of the sixth resistor, the other end of the sixth resistor is connected to a second node, the second node is a connection node between the other end of the sampling resistor and one end of the load resistor, one end of the seventh resistor is connected to one end of the sixth resistor, and the other end of the seventh resistor is grounded.

[0011] Optionally, the AC current source module includes a filter submodule, a compensation circuit submodule and a voltage-controlled current source submodule; wherein the filter submodule includes a first-order RC low-pass filter and a fourth-order Sallen-Key filter, the first-order RC low-pass filter is composed of an eighth resistor, a third operational amplifier and a third capacitor, the first-order RC low-pass filter is used to achieve low-pass filtering of the signal and isolation between the front and back stages, the fourth-order Sallen-Key filter is composed of two two-order Sallen-Key filters in cascade, the first two-order Sallen-Key filter is composed of a ninth resistor, a tenth resistor, a fourth capacitor, a fifth capacitor and a fourth operational amplifier, and the second two-order Sallen-Key filter is composed of an eleventh resistor, a twelfth resistor, a sixth capacitor, a seventh capacitor and a fifth operational amplifier; the fourth-order Sallen-Key filter is used to reduce high-frequency harmonic noise, and the filter submodule also includes a sixth operational amplifier and a thirteenth resistor.

[0012] Optionally, the compensation circuit submodule is an RC circuit composed of a fourteenth resistor and an eighth capacitor, one end of the compensation circuit submodule is connected to the input signal, and the other end of the compensation circuit submodule is grounded; the voltage-controlled current source submodule is a Howland current pump circuit, and the voltage-controlled current source submodule is composed of the seventh operational amplifier, the fourteenth resistor, the fifteenth resistor, the sixteenth resistor, the seventeenth resistor, the eighteenth resistor, the nineteenth resistor, the twentieth resistor, the twenty-first resistor, the twenty-second resistor and the ninth capacitor.

[0013] Optionally, the human-computer interaction module sends a digital signal to the microcontroller module through the serial port, and the digital signal is used to determine the output voltage of the adjustable voltage input module, the waveform output type, frequency and peak value of the microcontroller module.

[0014] In a second aspect, a high-bandwidth constant current source device is provided, wherein the high-bandwidth constant current source device is used to execute the method of the first aspect.

[0015] In the scheme implemented by the above-mentioned high-bandwidth constant current source circuit and device, the circuit independently controls the DC current source module and the AC current source module, that is, the DC output or AC output is selected according to the specific application requirements, which improves the flexibility and efficiency of the circuit. Further independent control of the DC and AC current source modules can reduce the complexity and potential safety risks of the circuit, because each current source is only activated when needed; through the serial port connection between the human-computer interaction module and the microcontroller module, the user can easily input precise control instructions, and the microcontroller module can perform precise current output control according to the control instructions; the microcontroller module receives the trigger signal through the I / O port and determines the first output current according to the signal, so that the DC current source module can flexibly switch the output current to adapt to different application requirements; the microcontroller module is connected to the AC current source module, and can output a variety of waveform signals to achieve complex AC current output to meet the needs of various tests and application scenarios; the circuit design can support high-bandwidth current output and is suitable for application scenarios that require fast response and high-frequency signals; therefore, the microcontroller module can automatically receive and process the trigger signal, make corresponding current output adjustments, realize automatic control, reduce human intervention, and improve work efficiency and accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0017] Figure 1 1 is a schematic diagram of the module structure of a high-bandwidth constant current source circuit in one embodiment of the present invention;

[0018] Figure 2 is a circuit diagram of a DC current source module 400 according to an embodiment of the present invention;

[0019] Figure 3 FIG. 5 is a circuit diagram of an AC current source module 500 according to an embodiment of the present invention. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0021] It should be noted that, if there is no conflict, the various features in the embodiments of the present application can be combined with each other, all within the scope of protection of the present application. In addition, although the functional module division is performed in the device schematic diagram and the logical order is shown in the flow chart, in some cases, the steps shown or described can be performed in a sequence different from the module division in the device or the flow chart. Furthermore, the words "first", "second", "third", etc. used in this application do not limit the data and execution order, but only distinguish the same items or similar items with basically the same functions and effects.

[0022] The present invention is described in detail below through specific embodiments.

[0023] In view of this, the present application proposes a high-bandwidth constant current source method to solve the above problems, which is described in detail below.

[0024] See also Figure 1 , Figure 1 A module schematic diagram of a high-bandwidth constant current source circuit provided by an embodiment of the present invention, the circuit includes: a human-computer interaction module, a microcontroller module, an adjustable reference voltage module, a direct current source module, and an alternating current source module; the microcontroller module is connected to the human-computer interaction module through a serial port, the microcontroller module is connected to a digital-to-analog converter submodule in the adjustable reference voltage module, the microcontroller module receives a trigger signal through an I / O port, and determines a first output current according to the trigger signal; the microcontroller module is connected to the alternating current source module, the microcontroller module outputs a waveform signal to the alternating current source module, the direct current source module is used to switch the first output current according to the trigger signal, the alternating current source module is used to output a second output current according to the input waveform signal, and the first output current or the second output current is output in the high-bandwidth constant current source circuit.

[0025] The module structure diagram of the high bandwidth constant current source circuit is as follows: Figure 1 As shown. Figure 1 In the embodiment, the circuit 10 includes: a human-computer interaction module 100, a microcontroller module 200, an adjustable reference voltage module 300, a DC current source module 400, and an AC current source module 500; the DC current source module 400 includes an error amplifier submodule 401, a power amplifier submodule 402, and a sampling feedback circuit submodule 403; the AC current source module 500 includes a filter submodule 501, a compensation circuit submodule 502, and a voltage-controlled current source submodule 503.

[0026] Optionally, in Figure 1The circuit also includes a power supply module 700 for providing working voltage for each module; the power supply module is electrically connected to the microcontroller module, the adjustable reference voltage module, the DC current source module and the AC current source module to ensure the normal operation of each module.

[0027] Specifically, the human-computer interaction module 100 is used for interaction between the user and the circuit system. The user can input control commands and parameters through the module, and the high-bandwidth constant current source circuit can display status information and feedback to the user through the module; the microcontroller module 200 is the core control unit of the circuit, which is connected to the human-computer interaction module 100 through a serial port to receive user instructions. The microcontroller module 200 is also connected to the digital-to-analog converter (DAC) submodule in the adjustable reference voltage module to generate an accurate reference voltage, so that the user can adjust the reference voltage through the software interface to further accurately control the current output; the microcontroller module receives a trigger signal through the I / O port, determines and controls the first output current according to the signal, and notifies the DC current source module 400 to perform corresponding current switching; the adjustable reference voltage module 300 includes a reference voltage submodule and a digital-to-analog converter (DAC) submodule, which are used to generate an adjustable reference voltage for use by the DC and AC current source modules; the microcontroller module 200 is connected to the AC current source module 500 to output a waveform signal to it to control the output of the AC current source module (second output current); the DC current source module 400 is used to output the first output current according to the trigger signal of the microcontroller, and the module includes the following submodules: the error amplifier submodule 401 is used to amplify the error of the feedback voltage of the adjustable reference voltage module 300 and the sampling feedback circuit submodule 403, and adjust the power amplifier submodule 402 to adjust the base current of the tube to output a high and stable output current; the power amplifier submodule 402: is used to amplify the output signal of the error amplifier submodule 401, and drive the current source to provide sufficient output current; the sampling feedback circuit submodule 403 is used to monitor the output current in real time, and send the feedback signal back to the error amplifier submodule to achieve closed-loop control; the AC current source module 500 is used to generate the second output current according to the waveform signal output by the microcontroller, and the module includes the following submodules: the filter submodule 501: is used to filter out the clutter in the waveform signal to ensure the purity of the output signal; the compensation circuit submodule 502: is used to compensate for the phase and gain errors in the system to ensure the stability of the output signal; the voltage-controlled current source submodule 503: generates the corresponding AC current according to the input waveform signal.

[0028] Among them, in the high-bandwidth constant current source circuit, the first output current or the second output current can be output as needed, which provides higher flexibility and application range for the current source.

[0029] It can be seen that in this embodiment, the circuit can meet various test and measurement requirements, provide stable and adjustable DC and AC current outputs, and has the characteristics of high bandwidth, fast response and user-friendliness.

[0030] The circuit independently controls the DC current source module and the AC current source module, that is, the DC output or the AC output is selected according to the specific application requirements, which improves the flexibility and efficiency of the circuit. Further independent control of the DC and AC current source modules can reduce the complexity and potential safety risks of the circuit, because each current source is activated only when needed; through the serial port connection between the human-computer interaction module and the microcontroller module, the user can easily input precise control instructions, and the microcontroller module can perform precise current output control according to the control instructions; the microcontroller module receives the trigger signal through the I / O port, and determines the first output current according to the signal, so that the DC current source module can flexibly switch the output current to adapt to different application requirements; the microcontroller module is connected to the AC current source module, and can output a variety of waveform signals to achieve complex AC current output to meet the needs of various tests and application scenarios; the circuit design can support high-bandwidth current output and is suitable for application scenarios that require fast response and high-frequency signals; therefore, the microcontroller module can automatically receive and process the trigger signal, make corresponding current output adjustments, realize automatic control, reduce human intervention, and improve work efficiency and accuracy.

[0031] In a possible example, the adjustable reference voltage module 300 includes a reference voltage submodule and a digital-to-analog converter submodule, the first output voltage in the reference voltage submodule is connected to the positive reference voltage input terminal in the digital-to-analog converter submodule, the second output voltage in the reference voltage submodule is connected to the negative reference voltage input terminal in the digital-to-analog converter submodule, the three signal connection terminals in the digital-to-analog converter submodule are all connected to the microcontroller module, and the three signal connection terminals transmit data according to the timing of the communication protocol corresponding to the serial peripheral device interface in the microcontroller module; the reference voltage submodule provides a reference voltage for the digital-to-analog converter submodule.

[0032] Among them, the above three signal connection terminals are SCLK, SDIN, where is chip selection, low level is effective, SCLK is the communication clock, SDIN is the digital control signal, that is, the digital control signal is transmitted by the communication protocol corresponding to the serial peripheral device interface in the microcontroller module to make the DAC output the set voltage.

[0033] Among them, the serial peripheral interface is SPI, which is a high-speed, full-duplex, synchronous communication protocol, usually used for data transmission between microcontrollers and peripheral devices.

[0034] The reference voltage submodule is used to generate a stable reference voltage for use by the digital-to-analog converter (DAC) submodule. The reference voltage submodule has two output voltages, the first output voltage is connected to the positive reference voltage input terminal of the digital-to-analog converter submodule (DAC) as the positive reference voltage of the DAC; the second output voltage is connected to the negative reference voltage input terminal of the digital-to-analog converter submodule (DAC) as the negative reference voltage of the DAC.

[0035] The digital-to-analog converter (DAC) submodule converts digital signals into analog voltage outputs. Its input signal is transmitted by the microcontroller module through a serial communication protocol; the DAC submodule has three signal connection terminals connected to the microcontroller module.

[0036] Specifically, chip select Used to select the DAC submodule for communication, low level is effective, that is, the low level is effective signal, used to select the DAC and make it ready to receive data. When low level, the DAC is activated and can receive data from the microcontroller; Communication clock (SCLK): a clock signal used to synchronize data transmission, that is, it provides a clock pulse for data transmission. In each clock cycle, the microcontroller sends one bit of data through the SDIN line, and the DAC captures these data bits at the rising or falling edge of SCLK; Digital control signal (SDIN): used to transmit digital control signals, that is, digital data used to transmit microcontroller modules to DAC. The microcontroller sends the digital control signal to the DAC through the SPI communication protocol to set the output voltage.

[0037] It can be seen that in this embodiment, the microcontroller module can accurately control the analog voltage output by the DAC, and further achieve accurate control of the current source module in the entire circuit system by adjusting the output of the adjustable reference voltage module 300.

[0038] In a possible example, the DC current source module 400 includes an error amplification submodule 401, a power amplification submodule 402, and a sampling feedback circuit submodule 403; wherein one end of the error amplification submodule 401 is connected to one end of the power amplification submodule 402, the other end of the error amplification submodule 401 is connected to one end of the sampling feedback circuit submodule 403, and the other end of the power amplification submodule 402 is connected to the other end of the sampling feedback circuit submodule 403.

[0039] The circuit diagram of the DC current source module 400 is as follows: Figure 2 As shown, in Figure 2 , the circuit connections between the error amplification submodule 401, the power amplification submodule 402, and the sampling feedback circuit submodule 403 and the component connections of each submodule are described.

[0040] The main function of the error amplifier submodule 401 is to compare the difference between the reference voltage and the feedback voltage provided by the sampling feedback circuit submodule 403, and to amplify the difference. One of its input terminals is connected to one end of the power amplifier submodule 402, and the other input terminal is connected to one end of the sampling feedback circuit submodule 403. The function of the error amplifier submodule 401 is to ensure the accuracy of the output current, and to drive the power amplifier submodule 402 by amplifying the error signal to adjust the output current to be close to the set target value.

[0041] The power amplifier submodule 402 is responsible for providing sufficient power to drive the load. It receives the amplified signal from the error amplifier submodule 401 and amplifies it to a level sufficient to drive the load. One end of the power amplifier submodule 402 is connected to one end of the error amplifier submodule 401, and the other end is connected to the other end of the sampling feedback circuit submodule 403.

[0042] The sampling feedback circuit submodule 403 is used to monitor the output current and convert the current into a voltage signal, which is fed back to the error amplification submodule 401. One terminal of the sampling feedback circuit submodule 403 is connected to the other end of the error amplification submodule 401, and the other terminal is connected to the other end of the power amplification submodule 402. Through this connection, the sampling feedback circuit submodule 403 can provide a closed-loop control system to ensure the stability and accuracy of the output current.

[0043] In a specific implementation, the DC current source module 400 realizes the jump between the two currents according to the trigger signal 600. The TTL level of the external signal is connected to the I / O port of the microcontroller module for high and low level judgment. The user sets the current value 1 and the current value 2 through the human-computer interaction module. According to the judgment result, the microcontroller module transmits the digital control signal of setting the current value 1 to the DAC at a low level, and transmits the digital control signal of setting the current value 2 to the DAC at a high level. Furthermore, the numerical control information of the two current values ​​is stored in the allocated array. When the external trigger signal changes in real time, the microcontroller module can quickly extract the corresponding digital information, that is, the current value can be jumped accordingly in real time according to the external changes.

[0044] Specifically, the trigger signal 600 is a TTL (Transistor-Transistor Logic) level signal, which can be a high level (usually 5V) or a low level (usually 0V). This signal is connected to the I / O (input / output) port of the microcontroller module, and the microcontroller module determines the state of the external trigger signal by detecting the level state of this port.

[0045] The array stores digital control information for storing digital control signals of current value 1 and current value 2. In this way, when the external trigger signal changes, the microcontroller module can quickly extract the corresponding digital information from the array and send it to the DAC immediately.

[0046] Specifically, when the external trigger signal is at a low level, the microcontroller module recognizes this state and transmits a digital control signal corresponding to a current value of 1 to a digital-to-analog converter (DAC). After receiving this signal, the DAC converts it into an analog voltage, and then sets the current source to output a current value of 1 through the circuit system; when the external trigger signal is at a high level, the microcontroller module also recognizes this state, but this time transmits a digital control signal corresponding to a current value of 2 to the DAC. The DAC converts it into an analog voltage again, and sets the current source to output a current value of 2.

[0047] Therefore, since the microcontroller module can quickly respond to changes in the external trigger signal and has pre-stored the required digital control signal, the current source can jump between the current value 1 and the current value 2 in real time under the action of the external trigger signal.

[0048] It can be seen that the DC current source module 400 in this embodiment can provide a high-precision and high-stability DC current for the circuit system, meeting the requirements of various application scenarios.

[0049] In a possible example, the error amplification submodule 401 includes a first resistor, a second resistor, a first capacitor, a second capacitor and a first operational amplifier; wherein the first end of the first resistor is connected to the digital-to-analog converter submodule in the adjustable reference voltage module, the second end of the first resistor is connected to the reverse end of the first operational amplifier, the first end of the first capacitor is connected to the reverse end of the first operational amplifier, the second end of the first capacitor is connected to the output end of the first operational amplifier, the second resistor is connected in parallel with the second capacitor to obtain a first parallel end and a second parallel end, the first parallel end is connected to the reverse end of the first operational amplifier, the second parallel end is connected to the feedback end of the sampling feedback circuit submodule, and the in-phase end of the first operational amplifier is grounded.

[0050] Among them, Figure 2 As shown in the block diagram 401 in FIG. 1 , a first resistor R1, a second resistor R9, a first capacitor C1, a second capacitor C2 and a first operational amplifier U3.

[0051] Specifically, the error amplifier circuit 401 is composed of resistors R1, R9, C1 and an operational amplifier U3 to form an addition amplifier circuit, wherein R1=R9, which is used to obtain the difference between the input and feedback signals, and U3 is used as an error amplifier to amplify the tiny difference, thereby adjusting the base current of the adjustment tube. The first end of R1 is connected to the DAC output, and the second end is connected to the inverting end of the operational amplifier U3. The two ends of C1 are respectively connected to the inverting end and the output end of U3 to prevent the parasitic capacitance of the operational amplifier from affecting the stability of the circuit. R9 and C2 are respectively connected to the inverting end of U3 and the feedback end of the sampling feedback circuit submodule, and the feedback end can send a feedback signal V s , C2 is used for slight phase compensation to prevent the circuit from oscillating, and the in-phase end of U3 is grounded.

[0052] It can be seen that the error amplification submodule 401 in this embodiment ensures the stability and accuracy of the output current of the DC current source module 400, and at the same time, through closed-loop control, quickly responds to and compensates for load changes and environmental interference.

[0053] In a possible example, the power amplifier submodule includes a first triode, a second triode, a third triode, a fourth triode, a third resistor, a first bias current source and a second bias current source; wherein the collector of the first triode is connected to a positive power supply, the base of the first triode is connected to the base of the second triode, the emitter of the first triode is connected to a first end of the second bias current source, the second end of the second bias current source is connected to a negative power supply, and the third resistor is connected to the base of the first triode and the base of the second triode. The collector of the second transistor is connected to the negative power supply, the emitter of the second transistor is connected to the first end of the first bias current source, the second end of the first bias current source is connected to the positive power supply, the collector of the third transistor is connected to the positive power supply, the emitter of the third transistor is connected to the collector of the fourth transistor, the base of the third transistor is connected to the emitter of the second transistor, the emitter of the fourth transistor is connected to the negative power supply, and the base of the fourth transistor is connected to the emitter of the first transistor.

[0054] Among them, Figure 2 As shown in the block diagram 402 in FIG. 4 , the power amplifier module 402 includes a first transistor Q1 , a second transistor Q2 , a third transistor Q3 , a fourth transistor Q4 , a third resistor R2 , a first bias current source I1 , and a second bias current source I2 .

[0055] Specifically, the power amplifier circuit 402 adopts a complementary power amplifier structure, which outputs bipolar current according to the input voltage, including a symmetrical adjustment tube structure composed of Q1, Q2, Q3, and Q4, I1 and I2 are bias current sources, so that Q3 and Q4 are both in critical conduction or micro-conduction state.

[0056] The first transistor Q1 and the second transistor Q2 form a pair of complementary transistors, wherein Q1 is an NPN transistor and Q2 is a PNP transistor. The collector of Q1 is connected to the positive power supply, while the collector of Q2 is connected to the negative power supply, so that a bipolar current output can be achieved.

[0057] The base of Q1 and the base of Q2 are connected together through a third resistor R2. The function of R2 is to provide base bias and ensure that the base voltages of the two transistors are the same.

[0058] The third triode and the fourth triode also form a pair of complementary transistors, the collector of the third triode is connected to the positive power supply, and the collector of the fourth triode is connected to the collector of the third triode through the emitter of the third triode, forming a push-pull amplifier structure. The base of the third triode is connected to the emitter of the second triode, and the base of the fourth triode is connected to the emitter of the first triode. This connection method enables the third triode and the fourth triode to amplify the input signal according to the change of the emitter current of the first triode and the second triode.

[0059] It can be seen that in this circuit, by precisely controlling the bias current sources I1 and I2, it can be ensured that the power amplifier submodule can maintain high efficiency and stable performance under different working conditions.

[0060] In a possible example, the sampling feedback circuit submodule includes a sampling resistor, a second operational amplifier, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor and a load resistor; wherein one end of the sampling resistor is connected to the collector of the fourth transistor, one end of the fourth resistor is connected to a first node, the first node is a connection node between one end of the sampling resistor and the collector of the fourth transistor, the other two ends of the sampling resistor are connected to one end of the load resistor, the other end of the load resistor is grounded, the other end of the fourth resistor is connected to one end of the fifth resistor, the other end of the fourth resistor is connected to the reverse end of the second operational amplifier, the other end of the fifth resistor is connected to the output end of the second operational amplifier, the output end of the second operational amplifier is a feedback end, the same direction end of the second operational amplifier is connected to one end of the sixth resistor, the other end of the sixth resistor is connected to a second node, the second node is a connection node between the other end of the sampling resistor and one end of the load resistor, one end of the seventh resistor is connected to one end of the sixth resistor, and the other end of the seventh resistor is grounded.

[0061] Among them, Figure 2 As shown in the block diagram 402 in FIG. 1 , the sampling feedback circuit submodule 403 includes a sampling resistor R s , a second operational amplifier U4, a fourth resistor R4, a fifth resistor R8, a sixth resistor R6, a seventh resistor R7 and a load resistor R L .

[0062] The sampling resistor is used to detect the current flowing through the load; the second operational amplifier forms an inverting amplifier circuit for converting the voltage signal on the sampling resistor into a feedback voltage.

[0063] The sampling feedback circuit submodule converts the output current into a feedback voltage through an inverting amplifier composed of U4, R4, R6, R7, and R8, and sums the feedback voltage with the input voltage of the error amplifier circuit 401 to achieve a closed-loop current stabilization effect.

[0064] Among them, the current output formula is as follows:

[0065]

[0066] Among them, V ref is the DAC output voltage signal, R s The sampling resistor is 0.1Ω, that is, the output current is controlled by the program-controlled voltage.

[0067] In a specific implementation, when current flows through the sampling resistor, a voltage drop is generated at both ends thereof, and this voltage is proportional to the current flowing through the load; the second operational amplifier and its peripheral resistors constitute an inverting amplifier, which amplifies the voltage signal on the sampling resistor and converts it into a feedback voltage; the feedback voltage is sent back to the input end of the error amplifier circuit 401 and compared with the reference voltage; by comparing the reference voltage and the feedback voltage, the error amplifier circuit 401 adjusts its output to control the power amplifier submodule 402, thereby maintaining the stability of the output current. This closed-loop control mechanism ensures that the output current remains constant even when external conditions change.

[0068] It can be seen that the sampling feedback circuit submodule in this embodiment can effectively convert the change of the output current into a voltage signal, and realize the steady current control through the closed-loop feedback system, thereby improving the performance and reliability of the entire circuit system.

[0069] In a possible example, the AC current source module 500 includes a filter submodule 501, a compensation circuit submodule 502 and a voltage-controlled current source submodule 503; wherein the filter submodule includes a first-order RC low-pass filter and a fourth-order Sallen-Key filter, the first-order RC low-pass filter is composed of an eighth resistor, a third operational amplifier and a third capacitor, the first-order RC low-pass filter is used to achieve low-pass filtering of the signal and isolation between the front and back stages, the fourth-order Sallen-Key filter is composed of two two-order Sallen-Key filters in cascade, the first two-order Sallen-Key filter is composed of a ninth resistor, a tenth resistor, a fourth capacitor, a fifth capacitor and a fourth operational amplifier, and the second two-order Sallen-Key filter is composed of an eleventh resistor, a twelfth resistor, a sixth capacitor, a seventh capacitor and a fifth operational amplifier; the fourth-order Sallen-Key filter is used to reduce high-frequency harmonic noise, and the filter submodule also includes a sixth operational amplifier and a thirteenth resistor.

[0070] Among them, Figure 3 As shown in the block diagram 501 in FIG. 1 , the first-order RC low-pass filter is composed of an eighth resistor R1, a third operational amplifier U1 and a third capacitor C1.

[0071] Among them, Figure 3 As shown in the block diagram 501 in FIG. 1 , the first two-order Sallen-Key filter is composed of a ninth resistor R2, a tenth resistor R3, a fourth capacitor C2, a fifth capacitor C3 and a fourth operational amplifier U2; the second two-order Sallen-Key filter is composed of an eleventh resistor R4, a twelfth resistor R5, a sixth capacitor C4, a seventh capacitor C5 and a fifth operational amplifier U3.

[0072] Among them, Figure 3The filter submodule 501 further includes a sixth operational amplifier U4 and a thirteenth resistor R6.

[0073] In a specific implementation, the filter circuit 501 is composed of a first-order RC low-pass filter and a fourth-order Sallen-Key filter, wherein R1, C1 and U1 constitute an RC low-pass filter and front-end and back-end isolation, and R2, R3, C2, C3, U2 and R4, R5, C4, C5, U3 respectively constitute two two-order Sallen-Key filters, the purpose of which is to reduce high-frequency harmonic noise. The operational amplifier U4 is designed as a follower, and one end of the resistor R6 is connected to the input signal and the other end is grounded, that is, the AC signal impedance to the ground, which is used to match the impedance with the front-end signal source.

[0074] In a possible example, the compensation circuit submodule is an RC circuit composed of a fourteenth resistor and an eighth capacitor, one end of the compensation circuit submodule is connected to the input signal, and the other end of the compensation circuit submodule is grounded; the voltage-controlled current source submodule is a Howland current pump circuit, and the voltage-controlled current source submodule is composed of the seventh operational amplifier, the fourteenth resistor, the fifteenth resistor, the sixteenth resistor, the seventeenth resistor, the eighteenth resistor, the nineteenth resistor, the twentieth resistor, the twenty-first resistor, the twenty-second resistor and the ninth capacitor.

[0075] Among them, Figure 3 As shown in the block diagram 502 in FIG. 1 , the compensation circuit submodule is an RC circuit composed of a fourteenth resistor R7 and an eighth capacitor C6. One end of the compensation circuit submodule is connected to the input signal, and the other end of the compensation circuit submodule is grounded to perform lead-lag compensation on the entire loop and adjust the dynamic response and stability of the circuit. The main function of the lead compensator is to increase the phase margin of the circuit, improve the response speed of the circuit, reduce overshoot, and thus increase the stability of the circuit. The lag compensator is used to improve the steady-state accuracy of the circuit and improve the low-frequency gain. The combined use of the two compensation effects effectively optimizes the overall performance of the circuit. When the input is a signal rich in high-order harmonics, such as a rectangular wave, the compensation can reduce overshoot by selecting appropriate RC parameters.

[0076] In the specific implementation, the zero point added to the loop after compensation is assumed to be z, and the pole is assumed to be p, and the transfer function is in the form of:

[0077]

[0078] Where |z|<|p|, the phase margin of the circuit is increased in this way.

[0079] Among them, Figure 3 As shown in the block diagram 502 in FIG. 1 , the voltage-controlled current source submodule is composed of the seventh operational amplifier U6, the fourteenth resistor R8, the fifteenth resistor R9, the sixteenth resistor R 10 17th resistor R11 , Eighteenth resistance R 16 , 19th resistor R 12 、The 20th resistor R 13 , the second resistor R 14 , the second resistor R 15 and a ninth capacitor C7.

[0080] In a specific implementation, the structure of the voltage-controlled current source submodule 503 is a Howland current pump circuit with a power amplifier as the core. The Howland current pump circuit is composed of U6, R8, R9, R 10 , R 11 , R 16 , R 12 , R 13 , R 14 , R 15 , C7. Among them, R8 / R 11 The ratio of R9 / R 10 If R0=R 12 / / R 13 / / R 14 / / R 15 C7 is connected in parallel with the inverting feedback resistor, and usually a smaller capacity of 1pF to several tens of pF is selected to play the role of a differential circuit and improve the circuit's anti-interference ability. 11 Introducing positive feedback, through R 10 Introducing negative feedback, when the load impedance decreases during transient state, I L Increase, while u p Down, u o Descending, I L Reduce to achieve the circuit current stabilization effect.

[0081] It can be seen that the voltage-controlled current source submodule can provide a precisely controllable AC current output according to the change of the input signal, while the compensation circuit submodule 502 ensures the stability and response performance of the entire current source module, and thus the circuit configuration is suitable for applications requiring a high-precision and high-stability current source.

[0082] In a possible example, the human-computer interaction module 100 sends a digital signal to the microcontroller module 200 through the serial port, and the digital signal is used to determine the output voltage of the adjustable voltage input module 300, the waveform output type, frequency and peak value of the microcontroller module 200.

[0083] The digital signal may be a parameter set by a user through a graphical user interface (GUI), key input or other input devices.

[0084] Optionally, the user can set the output voltage value of the adjustable voltage input module 300 through the human-computer interaction module 100. These settings are sent to the microcontroller module 200 in the form of digital signals through the serial port, and the microcontroller module 200 then adjusts the output voltage through the digital-to-analog converter (DAC) submodule according to these parameters.

[0085] Optionally, the user can also set the waveform type generated by the microcontroller module 200 through the human-computer interaction module 100, such as a sine wave, a square wave, a triangle wave, etc. The human-computer interaction module 100 sends the waveform type selected by the user to the microcontroller module 200 in the form of a digital signal, and the microcontroller module 200 generates a corresponding waveform through its internal or external waveform generator according to these instructions.

[0086] Optionally, the user can set the frequency of the output waveform through the human-computer interaction module 100. This frequency parameter is also sent to the microcontroller module 200 in the form of a digital signal, and the microcontroller module 200 adjusts the output frequency of the waveform generator accordingly.

[0087] Optionally, the user can also set the peak value of the output waveform, that is, the maximum voltage value of the waveform, through the human-computer interaction module 100. The human-computer interaction module 100 sends this peak parameter to the microcontroller module 200, and the microcontroller module 200 adjusts the size of its output signal to meet the peak requirement set by the user.

[0088] It can be seen that the design of the human-computer interaction module in this embodiment allows the user to flexibly configure and control the system so that the circuit can be adjusted according to different testing and measurement requirements.

[0089] It should be noted that in Figure 2-Figure 3 There are different components with the same symbols. For details, please refer to the drawings to which each component belongs and the modules in the drawings.

[0090] It should be noted that, in each of the above-mentioned embodiments, there is not necessarily a certain order between the above-mentioned steps. A person skilled in the art can understand, based on the description of the embodiments of the present application, that in different embodiments, the above-mentioned steps may have different execution orders, that is, they may be executed in parallel, may be executed interchangeably, and so on.

[0091] As another aspect of the embodiment of the present application, the embodiment of the present application provides a high-bandwidth constant current source device. Wherein, the high-bandwidth constant current source device can be a software module, and the software module includes a number of instructions, which are stored in a memory, and the processor can access the memory and call the instructions for execution to complete the high-bandwidth constant current source method described in each of the above embodiments.

[0092] To achieve the above object, the present invention further proposes a high-bandwidth constant current source device, the high-bandwidth constant current source device comprising the high-bandwidth constant current source circuit as described above. The specific structure of the high-bandwidth constant current source circuit refers to the above embodiment. Since the high-bandwidth constant current source device adopts all the technical solutions of all the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be repeated here one by one.

[0093] A person skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium, and when the program is executed, it can include the processes of the embodiments of the above-mentioned methods. The storage medium can be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc.

[0094] The above disclosure is only the preferred embodiment of the present application, which certainly cannot be used to limit the scope of rights of the present application. Therefore, equivalent changes made according to the claims of the present application are still within the scope covered by the present application.

Claims

1. A high-bandwidth constant current source circuit, characterized in that: The circuit includes: a human-computer interaction module, a microcontroller module, an adjustable reference voltage module, a DC current source module, and an AC current source module; the microcontroller module is connected to the human-computer interaction module via a serial port, the microcontroller module is connected to the digital-to-analog converter submodule in the adjustable reference voltage module, the microcontroller module receives a trigger signal via an I / O port, and determines a first output current based on the trigger signal; the microcontroller module is connected to the AC current source module, the microcontroller module outputs a waveform signal to the AC current source module, the DC current source module is used to switch the first output current based on the trigger signal, the AC current source module is used to output a second output current based on the input waveform signal, and the first output current or the second output current is output in the high-bandwidth constant current source circuit.

2. The circuit according to claim 1, wherein: The adjustable reference voltage module includes a reference voltage submodule and a digital-to-analog converter submodule. The first output voltage of the reference voltage submodule is connected to the positive reference voltage input terminal of the digital-to-analog converter submodule, and the second output voltage of the reference voltage submodule is connected to the negative reference voltage input terminal of the digital-to-analog converter submodule. The three signal connection terminals of the digital-to-analog converter submodule are all connected to the microcontroller module. The three signal connection terminals perform data transmission according to the timing of the communication protocol corresponding to the serial peripheral device interface in the microcontroller module; the reference voltage submodule provides a reference voltage for the digital-to-analog converter submodule.

3. The circuit according to claim 1, wherein: The DC current source module includes an error amplifier submodule, a power amplifier submodule, and a sampling feedback circuit submodule; wherein, one end of the error amplifier submodule is connected to one end of the power amplifier submodule, the other end of the error amplifier submodule is connected to one end of the sampling feedback circuit submodule, and the other end of the power amplifier submodule is connected to the other end of the sampling feedback circuit submodule.

4. The circuit according to claim 3, characterized in that The error amplification submodule includes a first resistor, a second resistor, a first capacitor, a second capacitor and a first operational amplifier; wherein, the first end of the first resistor is connected to the digital-to-analog converter submodule in the adjustable reference voltage module, the second end of the first resistor is connected to the reverse end of the first operational amplifier, the first end of the first capacitor is connected to the reverse end of the first operational amplifier, the second end of the first capacitor is connected to the output end of the first operational amplifier, the second resistor and the second capacitor are connected in parallel to obtain a first parallel end and a second parallel end, the first parallel end is connected to the reverse end of the first operational amplifier, the second parallel end is connected to the feedback end of the sampling feedback circuit submodule, and the non-inverting end of the first operational amplifier is grounded.

5. The circuit according to claim 3, characterized in that The power amplifier module includes a first transistor, a second transistor, a third transistor, a fourth transistor, a third resistor, a first bias current source and a second bias current source; wherein the collector of the first transistor is connected to the positive power supply, the base of the first transistor is connected to the base of the second transistor, the emitter of the first transistor is connected to the first end of the second bias current source, the second end of the second bias current source is connected to the negative power supply, the third resistor is connected to the base of the first transistor and the base of the second transistor, and the emitter of the first transistor is connected to the first end of the second bias current source, and the second end of the second bias current source is connected to the negative power supply. The collector of the first transistor is connected to the negative power supply, the emitter of the second transistor is connected to the first end of the first bias current source, the second end of the first bias current source is connected to the positive power supply, the collector of the third transistor is connected to the positive power supply, the emitter of the third transistor is connected to the collector of the fourth transistor, the base of the third transistor is connected to the emitter of the second transistor, the emitter of the fourth transistor is connected to the negative power supply, and the base of the fourth transistor is connected to the emitter of the first transistor.

6. The circuit according to claim 3, characterized in that The sampling feedback circuit submodule includes a sampling resistor, a second operational amplifier, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, and a load resistor; wherein one end of the sampling resistor is connected to the collector of the fourth transistor, one end of the fourth resistor is connected to a first node, which is a connection node between one end of the sampling resistor and the collector of the fourth transistor, the other two ends of the sampling resistor are connected to one end of the load resistor, the other end of the load resistor is grounded, the other end of the fourth resistor is connected to one end of the fifth resistor, the other end of the fourth resistor is connected to the inverting terminal of the second operational amplifier, the other end of the fifth resistor is connected to the output terminal of the second operational amplifier, the output terminal of the second operational amplifier is a feedback terminal, the non-inverting terminal of the second operational amplifier is connected to one end of the sixth resistor, the other end of the sixth resistor is connected to a second node, which is a connection node between the other end of the sampling resistor and one end of the load resistor, one end of the seventh resistor is connected to one end of the sixth resistor, and the other end of the seventh resistor is grounded.

7. The circuit according to claim 1, wherein: The AC current source module includes a filter submodule, a compensation circuit submodule and a voltage-controlled current source submodule; wherein, the filter submodule includes a first-order RC low-pass filter and a fourth-order Sallen-Key filter, the first-order RC low-pass filter is composed of an eighth resistor, a third operational amplifier and a third capacitor, the first-order RC low-pass filter is used to achieve low-pass filtering of the signal and isolation of the front and back stages, the fourth-order Sallen-Key filter is composed of two two-order Sallen-Key filters in cascade, the first two-order Sallen-Key filter is composed of a ninth resistor, a tenth resistor, a fourth capacitor, a fifth capacitor and a fourth operational amplifier, and the second two-order Sallen-Key filter is composed of an eleventh resistor, a twelfth resistor, a sixth capacitor, a seventh capacitor and a fifth operational amplifier; the fourth-order Sallen-Key filter is used to reduce high-frequency harmonic noise, and the filter submodule also includes a sixth operational amplifier and a thirteenth resistor.

8. The circuit according to claim 7, characterized in that The compensation circuit submodule is an RC circuit consisting of a fourteenth resistor and an eighth capacitor, one end of the compensation circuit submodule is connected to the input signal, and the other end of the compensation circuit submodule is grounded; the voltage-controlled current source submodule is a Howland current pump circuit, and the voltage-controlled current source submodule is composed of the seventh operational amplifier, the fourteenth resistor, the fifteenth resistor, the sixteenth resistor, the seventeenth resistor, the eighteenth resistor, the nineteenth resistor, the twentieth resistor, the twenty-first resistor, the twenty-second resistor and the ninth capacitor.

9. The circuit according to claim 1, wherein: The human-computer interaction module sends a digital signal to the microcontroller module through the serial port, and the digital signal is used to determine the output voltage of the adjustable voltage input module, the waveform output type, frequency and peak value of the microcontroller module.

10. A high-bandwidth constant current source device, characterized in that: The high-bandwidth constant current source device comprises the high-bandwidth constant current source circuit according to any one of claims 1 to 9.

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