A high-bandwidth constant current source circuit and device

Abstract

This application relates to the field of circuit design, specifically to a high-bandwidth constant current source circuit and device. The circuit includes: a human-machine interface 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-machine interface module via a serial port and is also connected to the 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 based on the trigger signal. The microcontroller module is connected to the AC current source module and outputs a waveform signal to the AC current source module. The DC current source module switches the first output current according to the trigger signal, and the AC current source module outputs a second output current based on the input waveform signal. This invention improves the stability of both AC and DC current.

Description

Technical Field

[0001] This application relates to the field of circuit design, and more particularly to a high-bandwidth constant current source circuit and device. Background Technology

[0002] A constant current source is a power supply device capable of outputting a constant current, widely used in electronic equipment manufacturing, testing, calibration, automation, and laboratories. Its role is particularly crucial in cold atom experiments, requiring wide bandwidth, high stability, fast response, rapid switching, and long-term stable operation. However, existing commercially available constant current sources often suffer from high noise and low current stability, making them unsuitable for the demands of precision experiments. For example, in cold atom experiments, they require a highly stable magnetic field; in fields such as nuclear magnetic resonance imaging in medical devices and precise chemical reactions in electrochemical applications, the stability and accuracy of the current source are extremely critical. Furthermore, many experiments require rapid changes in current, necessitating a current source with a fast switching response and sufficient bandwidth. For instance, different stages of a cold atom experiment may require magnetic fields of varying magnitudes, corresponding to current demands ranging from milliamps to several amps. This not only requires rapid current switching but also, sometimes, rapid on / off switching, placing high demands on circuit bandwidth.

[0003] Traditional constant current sources often employ a single 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 primarily single-function and cannot be timed via external TTL signals. High-precision, high-current constant current sources are expensive, and experiments often require constant current sources with multiple functions, which complicates the use of the equipment and increases operating costs. Summary of the Invention

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

[0005] In a first aspect, a high-bandwidth constant current source circuit is provided. The circuit includes: a human-machine interface 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-machine interface module via a serial port and to a 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 and outputs a waveform signal to the AC current source module. The DC current source module is used to switch the first output current according to the trigger signal, and the AC current source module is used to output a second output current according to the input waveform signal. The high-bandwidth constant current source circuit outputs either the first output current or the second output current.

[0006] Optionally, 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, and the data transmission of the three signal connection terminals is performed 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 to the digital-to-analog converter submodule.

[0007] Optionally, the DC current source module includes an error amplification submodule, a power amplification submodule, and a sampling feedback circuit submodule; wherein, one end of the error amplification submodule is connected to one end of the power amplification submodule, the other end of the error amplification submodule is connected to one end of the sampling feedback circuit submodule, and the other end of the power amplification 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 inverting terminal of the first operational amplifier, the first end of the first capacitor is connected to the inverting terminal of the first operational amplifier, the second end of the first capacitor is connected to the output terminal of the first operational amplifier, the second resistor and the second capacitor are connected in parallel to form a first parallel terminal and a second parallel terminal, the first parallel terminal is connected to the inverting terminal of the first operational amplifier, the second parallel terminal is connected to the feedback terminal of the sampling feedback circuit submodule, and the non-inverting terminal of the first operational amplifier is grounded.

[0009] Optionally, the power amplifier submodule 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 a 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 a first terminal of the second bias current source, the second terminal of the second bias current source is connected to a negative power supply, the third resistor is connected to the bases of the first transistor and the second transistor, and the third... The collector of the second transistor is connected to the negative power supply, the emitter of the second transistor is connected to the first terminal of the first bias current source, the second terminal 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.

[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 transistor, one end of the fourth resistor is connected to a first node, the first node being the 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 input of the second operational amplifier, the other end of the fifth resistor is connected to the output input of the second operational amplifier, the output input of the second operational amplifier is the feedback input, the non-inverting input 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 being the 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, and is used to achieve low-pass filtering and isolation between preceding and following stages of the signal; the fourth-order Sallen-Key filter is composed of two cascaded second-order Sallen-Key filters, the first second-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 second-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 the fourteenth resistor and the eighth capacitor. One end of the compensation circuit submodule is connected to the input signal, and the other end is grounded. The voltage-controlled current source submodule is a Howland current pump circuit, which 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-machine interaction module sends digital signals to the microcontroller module through the serial port. The digital signals are 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 for performing the method as described in the first aspect above.

[0015] In the above-described high-bandwidth constant current source circuit and device, the circuit independently controls the DC current source module and the AC current source module. This allows for selection of either DC or AC output based on specific application requirements, improving the circuit's flexibility and efficiency. Furthermore, independent control of the DC and AC current source modules reduces circuit complexity and potential safety risks, as each current source is only activated when needed. Through the serial port connection between the human-machine interface module and the microcontroller module, users can easily input precise control commands, which the microcontroller module can then use to precisely control the current output. The microcontroller module receives trigger signals via I / O ports and determines the first output current based on these signals, enabling the DC current source module to flexibly switch output currents to adapt to different application requirements. The microcontroller module, connected to the AC current source module, can output various waveform signals to achieve complex AC current outputs, meeting the needs of various testing and application scenarios. The circuit design supports high-bandwidth current output, making it suitable for applications requiring fast response and high-frequency signals. Therefore, the microcontroller module can automatically receive and process trigger signals, adjusting the current output accordingly to achieve automated control, reducing human intervention and improving work efficiency and accuracy. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This 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 This is a circuit diagram of a DC current source module 400 in one embodiment of the present invention;

[0019] Figure 3 This is a circuit diagram of an AC current source module 500 in one embodiment of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0021] It should be noted that, unless there is a conflict, the various features in the embodiments of this application can be combined with each other, all of which are within the protection scope of this application. Furthermore, although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than the module division in the device or the order in the flowchart. Moreover, the terms "first," "second," and "third" used in this application do not limit the data or execution order, but only distinguish identical or similar items with essentially the same function and effect.

[0022] The present invention will now be described in detail through specific embodiments.

[0023] In view of this, this application proposes a high-bandwidth constant current source method to solve the above problems. The details are described below.

[0024] Please see Figure 1 , Figure 1 This is a schematic diagram of a high-bandwidth constant current source circuit provided in an embodiment of the present invention. The circuit includes: a human-machine interface 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-machine interface module via a serial port and to the 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 based on the trigger signal. The microcontroller module is connected to the AC current source module and outputs a waveform signal to the AC current source module. The DC current source module is used to switch the first output current according to the trigger signal, and the AC current source module is used to output a second output current according to the input waveform signal. The circuit outputs either the first output current or the second output current 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. In Figure 1 In this circuit 10, the components include: a human-machine 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 amplification submodule 401, a power amplification 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, which provides operating voltage to 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 that each module works normally.

[0027] Specifically, the human-machine interface module 100 is used for interaction between the user and the circuit system. The user can input control commands and parameters through this module, and the high-bandwidth constant current source circuit can display status information and feedback to the user through this module. The microcontroller module 200 is the core control unit of the circuit. It is connected to the human-machine interface module 100 via a serial port to receive user commands. The microcontroller module 200 is also connected to the digital-to-analog converter (DAC) submodule in the adjustable reference voltage module to generate a precise reference voltage, allowing the user to adjust the reference voltage through a software interface for further precise control of the current output. The microcontroller module receives a trigger signal through an I / O port, determines and controls the first output current based on this signal, and notifies the DC current source module 400 to perform the corresponding current switching. The adjustable reference voltage module 300 includes a reference voltage submodule and a digital-to-analog converter (DAC) submodule 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, outputting waveform signals to it to control the output of the AC current source module. (Second Output Current); DC current source module 400 is used to output a first output current according to the trigger signal of the microcontroller. This module includes the following sub-modules: error amplification sub-module 401 is used to amplify the feedback voltage of the adjustable reference voltage module 300 and the sampling feedback circuit sub-module 403, and adjust the base current of the adjusting transistor of the power amplification sub-module 402 to output a highly stable output current; power amplification sub-module 402: is used to amplify the output signal of error amplification sub-module 401 and drive the current source to provide sufficient output current; sampling feedback circuit sub-module 403 is used to monitor the output current in real time and send the feedback signal back to the error amplification sub-module to realize closed-loop control; AC current source module 500 is used to generate a second output current according to the waveform signal output by the microcontroller. This module includes the following sub-modules: filter sub-module 501: is used to filter out noise in the waveform signal to ensure the purity of the output signal; compensation circuit sub-module 502: is used to compensate for phase and gain errors in the system to ensure the stability of the output signal; voltage-controlled current source sub-module 503: generates a corresponding AC current according to the input waveform signal.

[0028] In particular, in the high-bandwidth constant current source circuit, the first output current or the second output current can be output as needed, which provides the current source with greater flexibility and application range.

[0029] As can be seen, in this embodiment, the circuit can meet various testing and measurement needs, providing stable and adjustable DC and AC current outputs, while also featuring high bandwidth, fast response, and user-friendliness.

[0030] This circuit independently controls both the DC and AC current source modules, allowing users to select either DC or AC output based on specific application requirements. This enhances the circuit's flexibility and efficiency. Furthermore, independent control of the DC and AC current source modules reduces circuit complexity and potential safety risks, as each current source is only activated when needed. Through a serial port connection between the human-machine interface module and the microcontroller module, users can easily input precise control commands, which the microcontroller module then uses to precisely control the current output. The microcontroller module receives trigger signals via I / O ports and determines the first output current based on these signals, enabling the DC current source module to flexibly switch output currents to adapt to different application needs. Connecting the microcontroller module to the AC current source module allows for the output of various waveform signals, enabling complex AC current outputs to meet the requirements of various testing and application scenarios. The circuit design supports high-bandwidth current output, making it suitable for applications requiring fast response and high-frequency signals. Therefore, the microcontroller module can automatically receive and process trigger signals, adjusting the current output accordingly to achieve automated control, reducing human intervention and improving efficiency and accuracy.

[0031] In one possible example, the adjustable reference voltage module 300 includes a reference voltage submodule and a digital-to-analog converter submodule. A first output voltage in the reference voltage submodule is connected to the positive reference voltage input terminal of the digital-to-analog converter submodule, and a second output voltage in the reference voltage submodule is connected to the negative reference voltage input terminal of the digital-to-analog converter submodule. Three signal connection terminals in the digital-to-analog converter submodule are all connected to the microcontroller module, and data is transmitted through these three signal connection terminals 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 to the digital-to-analog converter submodule.

[0032] Among them, the above three signal connection terminals are SCLK, SDIN, among which SCLK is the chip select signal, active low. SCLK is the communication clock, and SDIN is the numerical control signal. That is, the numerical control signal is transmitted through 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, typically used for data transmission between microcontrollers and peripheral devices.

[0034] The reference voltage submodule generates a stable reference voltage for use by the digital-to-analog converter (DAC) submodule. It has two output voltages: a first output voltage connected to the positive reference voltage input of the DAC, serving as the DAC's positive reference voltage; and a second output voltage connected to the negative reference voltage input of the DAC, serving as the DAC's negative reference voltage.

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

[0036] Specifically, film selection The SDIN line is used to select the DAC submodule for communication. It is active low, meaning a low-level signal is used to select the DAC and prepare it to receive data. When low, the DAC is activated and can receive data from the microcontroller. The SCLK (communication clock) is used to synchronize data transmission, providing the clock pulse for data transfer. Each clock cycle, the microcontroller sends one bit of data via the SDIN line, and the DAC captures these bits on the rising or falling edge of SCLK. The SDIN (digital control signal) is used to transmit digital control signals, i.e., digital data from the microcontroller module to the DAC. The microcontroller sends the SDIN signal to the DAC via the SPI communication protocol to set the output voltage.

[0037] As can be seen, in this embodiment, the microcontroller module can precisely control the analog voltage output by the DAC, and then, by adjusting the output of the adjustable reference voltage module 300, achieve precise control of the current source module in the entire circuit system.

[0038] In one 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 shown below. Figure 2 As shown, in Figure 2 The document describes the circuit connections between each submodule, including the error amplification submodule 401, the power amplification submodule 402, and the sampling feedback circuit submodule 403, as well as the component connections within each submodule.

[0040] The primary function of the error amplification submodule 401 is to compare the difference between the reference voltage and the feedback voltage provided by the sampling feedback circuit submodule 403, and amplify this difference. One input terminal is connected to one end of the power amplification submodule 402, and the other input terminal is connected to one end of the sampling feedback circuit submodule 403. The role of the error amplification submodule 401 is to ensure the accuracy of the output current by amplifying the error signal to drive the power amplification submodule 402, thereby adjusting the output current to approach 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 monitors the output current and converts it into a voltage signal, which is then 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 provides a closed-loop control system to ensure the stability and accuracy of the output current.

[0043] In practical implementation, the DC current source module 400 implements the switching between two set currents based on the trigger signal 600. The TTL level of the external signal is connected to the I / O port of the microcontroller module for high / low level judgment. The user sets current value 1 and current value 2 through the human-machine interface module. Based on the judgment result, the microcontroller module transmits a low-level digital control signal for setting current value 1 to the DAC, and a high-level digital control signal for setting current value 2 to the DAC. Furthermore, the digital control information of these two current values ​​is stored in an allocated array. When the external trigger signal changes in real time, the microcontroller module can quickly extract the corresponding digital information, meaning the current value can switch accordingly in real time based on external changes.

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

[0045] The array stores the digital control information, specifically the digital control signals for current value 1 and current value 2. This allows the microcontroller module to quickly retrieve the corresponding digital information from the array and immediately send it to the DAC when an external trigger signal changes.

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

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

[0048] As can be seen, the DC current source module 400 in this embodiment can provide high-precision and high-stability DC current to the circuit system, meeting the needs of various application scenarios.

[0049] In one 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 inverting terminal of the first operational amplifier, the first end of the first capacitor is connected to the inverting terminal of the first operational amplifier, the second end of the first capacitor is connected to the output terminal of the first operational amplifier, the second resistor and the second capacitor are connected in parallel to form a first parallel terminal and a second parallel terminal, the first parallel terminal is connected to the inverting terminal of the first operational amplifier, the second parallel terminal is connected to the feedback terminal of the sampling feedback circuit submodule, and the non-inverting terminal of the first operational amplifier is grounded.

[0050] Among them, such as Figure 2 As shown in the 401 block diagram, there is 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 consists of resistors R1, R9, capacitor C1, and operational amplifier U3, forming an adder amplifier circuit. R1 = R9, used to calculate the difference between the input and feedback signals. U3 acts as an error amplifier, amplifying the small difference to adjust the base current of the regulating transistor. The first terminal of R1 is connected to the DAC output, and the second terminal is connected to the inverting input of operational amplifier U3. The two terminals of capacitor C1 are connected to the inverting input and the output terminal of U3, respectively, to prevent the parasitic capacitance of the operational amplifier from affecting circuit stability. R9 and C2 are connected to the inverting input of U3 and the feedback terminal of the sampling feedback circuit submodule, respectively. The feedback terminal can send a feedback signal V. s C2 is for slight phase compensation to prevent circuit oscillation, and the non-inverting terminal of U3 is grounded.

[0052] As can be seen, in this embodiment, the error amplification submodule 401 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, it can quickly respond to and compensate for load changes and environmental interference.

[0053] In one possible example, the power amplifier submodule 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 a 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 a first terminal of the second bias current source, the second terminal of the second bias current source is connected to a negative power supply, and the third resistor is connected to the bases of the first transistor and the second transistor. The collector of the second transistor is connected to the negative power supply, the emitter of the second transistor is connected to the first terminal of the first bias current source, the second terminal 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, such as Figure 2 As shown in block diagram 402, the power amplifier submodule 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 employs a complementary power amplifier structure, which provides bipolar current output based on the input voltage. It includes a symmetrical regulating transistor structure composed of Q1, Q2, Q3, and Q4, with I1 and I2 serving as bias current sources, ensuring that transistors Q3 and Q4 are both in a critical or slightly conducting state.

[0056] In this configuration, transistors Q1 and Q2 form a complementary transistor pair, where 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. This configuration enables bipolar current output.

[0057] The bases of Q1 and 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] In this configuration, the third and fourth transistors form a complementary transistor pair. The collector of the third transistor is connected to the positive power supply, and the collector of the fourth transistor is connected to the collector of the third transistor through the emitter of the third transistor, forming a push-pull amplification structure. The base of the third transistor is connected to the emitter of the second transistor, while the base of the fourth transistor is connected to the emitter of the first transistor. This connection allows the third and fourth transistors to amplify the input signal based on changes in the emitter currents of the first and second transistors.

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

[0060] In one 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 being the 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 input of the second operational amplifier, the other end of the fifth resistor is connected to the output input of the second operational amplifier, the output input of the second operational amplifier is the feedback input, the non-inverting input 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 being the 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, such as Figure 2 As shown in block diagram 402, the sampling feedback circuit submodule 403 includes a sampling resistor R. s The second operational amplifier U4, the fourth resistor R4, the fifth resistor R8, the sixth resistor R6, the seventh resistor R7, and the 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 to convert the voltage signal on the sampling resistor into a feedback voltage.

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

[0064] The current output formula is as follows:

[0065]

[0066] Among them, V ref R is the output voltage signal of the DAC. s The sampling resistor is set to 0.1Ω, meaning the output current is controlled by the programmable voltage.

[0067] In practical implementation, when current flows through the sampling resistor, a voltage drop is generated across it, which is proportional to the current flowing through the load. The second operational amplifier and its peripheral resistors form an inverting amplifier, which amplifies the voltage signal across the sampling resistor and converts it into a feedback voltage. The feedback voltage is sent back to the input 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] As can be seen, the sampling feedback circuit submodule in this embodiment can effectively convert the change in output current into a voltage signal and achieve steady current control through a closed-loop feedback system, thereby improving the performance and reliability of the entire circuit system.

[0069] In one 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. 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 consists of an eighth resistor, a third operational amplifier, and a third capacitor. This first-order RC low-pass filter is used for low-pass filtering and isolation between preceding and following stages. The fourth-order Sallen-Key filter is composed of two cascaded second-order Sallen-Key filters. The first second-order Sallen-Key filter consists of a ninth resistor, a tenth resistor, a fourth capacitor, a fifth capacitor, and a fourth operational amplifier. The second second-order Sallen-Key filter consists 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. The filter submodule also includes a sixth operational amplifier and a thirteenth resistor.

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

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

[0072] Among them, such as Figure 3The filter submodule 501 described herein also includes a sixth operational amplifier U4 and a thirteenth resistor R6.

[0073] In its implementation, filter circuit 501 consists of a first-order RC low-pass filter and a fourth-order Sallen-Key filter. R1, C1, and U1 form the RC low-pass filter and provide isolation between the preceding and following stages. R2, R3, C2, C3, U2 and R4, R5, C4, C5, U3 respectively form two second-order Sallen-Key filters to reduce high-frequency harmonic noise. Operational amplifier U4 is designed as a follower. Resistor R6 has one end connected to the input signal and the other end grounded, representing the AC signal impedance to ground, used for impedance matching with the preceding signal source.

[0074] In one possible example, the compensation circuit submodule is an RC circuit consisting of the fourteenth resistor and the eighth capacitor, with one end of the compensation circuit submodule connected to the input signal and the other end grounded; the voltage-controlled current source submodule is a Howland current pump circuit, which consists 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, such as Figure 3 As shown in block diagram 502, the compensation circuit submodule consists of an RC circuit composed of the fourteenth resistor R7 and the eighth capacitor C6. One end of the compensation circuit submodule is connected to the input signal, and the other end is grounded to perform lead and lag compensation for the entire loop, adjusting 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 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 containing rich high-order harmonics, such as a rectangular wave, this compensation can reduce overshoot by selecting appropriate RC parameters.

[0076] In practical implementation, let z be the number of zeros added to the loop after compensation, and p be the number of poles. Its transfer function form is as follows:

[0077]

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

[0079] Among them, such as Figure 3 As shown in block diagram 502, the voltage-controlled current source submodule consists of the seventh operational amplifier U6, the fourteenth resistor R8, the fifteenth resistor R9, and the sixteenth resistor R... 10 The seventeenth resistor R11 The eighteenth resistance R 16 Nineteenth resistor R 12 The twentieth resistor R 13 The second resistor R 14 The second resistor R 15 It consists of the ninth capacitor C7.

[0080] In practical implementation, the voltage-controlled current source submodule 503 is structured as a Howland current pump circuit with a power operational amplifier as its core. The Howland current pump circuit consists of U6, R8, R9, and R... 10 R 11 R 16 R 12 R 13 R 14 R 15 Composed of C7. Where R8 / R 11 The ratio must be consistent with R9 / R 10 If they are matched, the output current is independent of the load and only depends on R0 = R 12 / / R 13 / / R 14 / / R 15 The relationship is linear. C7 is connected in parallel with the feedback resistor at the inverting input, and a relatively small capacitance, from 1pF to tens of pF, is typically chosen to act as a differentiating circuit, improving the circuit's anti-interference capability. This circuit connects to R... 11 Introducing positive feedback, and then through R 10 Introducing negative feedback, during transients when the load impedance decreases, I L Increase, and u p Decrease, u o Decrease, I L This reduces the current, achieving a stable current flow in the circuit.

[0081] As can be seen, the voltage-controlled current source submodule can provide precise and controllable AC current output according to the changes in the input signal. At the same time, the compensation circuit submodule 502 ensures the stability and response performance of the entire current source module. Thus, the circuit configuration is suitable for applications that require high-precision and high-stability current sources.

[0082] In one possible example, the human-computer interaction module 100 sends digital signals to the microcontroller module 200 via the serial port. The digital signals are 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 aforementioned digital signals may be parameters set by the 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-machine interface module 100. These settings are sent to the microcontroller module 200 in the form of digital signals via a serial port, and the microcontroller module 200 then adjusts the output voltage through the digital-to-analog converter (DAC) submodule based on these parameters.

[0085] Optionally, the user can also set the waveform type generated by the microcontroller module 200 through the human-machine interface module 100, such as sine wave, square wave, triangle wave, etc. The human-machine interface 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 the 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-machine interface 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, i.e., the maximum voltage value of the waveform, through the human-machine interface module 100. The human-machine interface module 100 sends this peak value parameter to the microcontroller module 200, which adjusts the magnitude of its output signal to meet the peak value requirement set by the user.

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

[0089] It is important to note that, in Figures 2-3 There are different components with the same symbol. Please refer to the attached diagram of each component and the module in the diagram for details.

[0090] It should be noted that in the above embodiments, there is no necessarily a certain order between the steps. Those skilled in the art can understand from the description of the embodiments of this application that the above steps may have different execution orders in different embodiments, that is, they may be executed in parallel or in turn, etc.

[0091] As another aspect of the embodiments of this application, this application provides a high-bandwidth constant current source device. The high-bandwidth constant current source device can be a software module, which includes several instructions stored in a memory. A processor can access the memory and execute the instructions to complete the high-bandwidth constant current source method described in the various embodiments above.

[0092] To achieve the above objectives, the present invention also proposes a high-bandwidth constant current source device, which includes the high-bandwidth constant current source circuit described above. The specific structure of this high-bandwidth constant current source circuit is as described in the above embodiments. Since this high-bandwidth constant current source device adopts all the technical solutions of all the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated upon here.

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

[0094] The above-disclosed embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of this application. Therefore, any equivalent variations made in accordance with the claims of this application shall still fall within the scope of this application.

Claims

1. A high-bandwidth constant current source circuit, characterized in that, The circuit includes: a human-machine 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-machine interface module via a serial port. The microcontroller module is also 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 the first output current based on the trigger signal. The microcontroller module is connected to the AC current source module, and 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 according to the trigger signal. The AC current source module is used to output a second output current according to the input waveform signal, and to output the first output current or the second output current in the high bandwidth constant current source circuit.

2. The circuit according to claim 1, characterized in that, 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, and the three signal connection terminals in the digital-to-analog converter submodule are all connected to the microcontroller module. 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.

3. The circuit according to claim 1, characterized in that, The DC current source module includes an error amplification submodule, a power amplification submodule, and a sampling feedback circuit submodule; wherein, one end of the error amplification submodule is connected to one end of the power amplification submodule, the other end of the error amplification submodule is connected to one end of the sampling feedback circuit submodule, and the other end of the power amplification 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; In this configuration, 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 inverting input of the first operational amplifier, the first end of the first capacitor is connected to the inverting input of the first operational amplifier, the second end of the first capacitor is connected to the output terminal of the first operational amplifier, the second resistor and the second capacitor are connected in parallel to form a first parallel terminal and a second parallel terminal, the first parallel terminal is connected to the inverting input of the first operational amplifier, the second parallel terminal is connected to the feedback terminal of the sampling feedback circuit submodule, and the non-inverting input of the first operational amplifier is grounded.

5. The circuit according to claim 3, characterized in that, The power amplifier submodule 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 a 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 a first terminal of the second bias current source, the second terminal of the second bias current source is connected to a negative power supply, one end of the third resistor is connected to the bases of the first transistor and the second transistor, and the other end of the third resistor is connected to one end of the error amplifier submodule; The collector of the second transistor is connected to the negative power supply, the emitter of the second transistor is connected to the first terminal of the first bias current source, the second terminal 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 5, 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 the first node, the first node being the connection node between one end of the sampling resistor and the collector of the fourth transistor, the other end of the sampling resistor is 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 input 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 the feedback terminal, the non-inverting input of the second operational amplifier is connected to one end of the sixth resistor, the other end of the sixth resistor is connected to the second node, the second node being the 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, the other end of the seventh resistor is grounded.

7. The circuit according to claim 1, characterized in that, The AC current source module includes a filter submodule, a compensation circuit submodule, and a voltage-controlled current source submodule. 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 consists of an eighth resistor, a third operational amplifier, and a third capacitor. This first-order RC low-pass filter is used to achieve low-pass filtering and isolation between preceding and following stages. The fourth-order Sallen-Key filter is composed of two cascaded second-order Sallen-Key filters.

8. The circuit according to claim 1, characterized in that, The human-computer interaction module sends digital signals to the microcontroller module through the serial port. The digital signals are used to determine the output voltage of the adjustable voltage input module, the waveform output type, frequency, and peak value of the microcontroller module.

9. A high-bandwidth constant current source device, characterized in that, The high-bandwidth constant current source device includes the high-bandwidth constant current source circuit according to any one of claims 1 to 8.

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