A current source control method, device, medium, processor and current source

Abstract

The application provides a current source control method, device, medium, processor and current source. The current source can output positive current and negative current, and comprises a power tube, an H-bridge circuit, a feedback loop and a DAC module. The DAC module is used to provide a variable reference source for the feedback loop to realize signal stage closed-loop control of the current source. The control method comprises: judging the current working state of the current source; when the working state is first powered on, the working timing of the H-bridge circuit and the DAC module is controlled, so that the time when the DAC module starts to establish and the time when the bridge arm of the H-bridge circuit is turned on tend to be consistent, thereby improving the response time of the current source output. The application can reduce the rise time when the H-bridge and the DAC module are turned on alone.

Description

Technical Field

[0001] This invention relates to the field of current control, and in particular to a control method, device, medium, processor and current source for a current source. Background Technology

[0002] In the field of precision current control, linear power supplies are typically used as voltage or current sources. Compared to switching power supplies, they offer lower ripple and noise, better meeting the demands of high-precision applications. Linear power supplies are usually controlled by a DAC and an analog loop. The analog loop output is converted into a drive signal for power devices, ultimately achieving precise current or voltage output. To meet high-resolution requirements, high-bit-count DACs and low-noise designs can be used to achieve high-precision, low-noise current or voltage output.

[0003] In AC output applications, DACs typically require both positive and negative references, and also need positive and negative power supplies. The typical formula for the analog signal output of a positive and negative DAC is Vout = (Vrefp - Vrefn). D / (2 N -1)+Vrefn, while the typical formula for the analog signal output of a unipolar output DAC is Vout=Vref D / (2 N -1), where Vout is the DAC output voltage, Vrefp is the positive reference voltage, Vrefn is the negative reference voltage, D is the set value, and N is the number of bits in the DAC. In AC output applications, the effective number of bits in the DAC is usually one more than in unidirectional output applications. In high-precision, high-resolution AC output applications, high-performance DACs account for a large proportion of the product cost. Combined with the requirements for positive and negative references and power supplies, this further increases the overall cost and design complexity of the product.

[0004] Chinese patent CN222545654U discloses a current source capable of AC output at the load end. This patent employs an H-bridge circuit, achieving precise positive and negative current output by controlling the switching on of one of the two bridge arms. However, the patent does not provide a detailed description of the control method. The inventors of this application have discovered the following problems with this patent:

[0005] (1) When powered on, if the H-bridge circuit is driven and the DAC is written with instructions at the same time, the delay will cause the DAC module output to start to be established at a time that is inconsistent with the time when the bridge arm of the H-bridge circuit is turned on, which will affect the system response speed. (2) When switching between positive and negative output current, if the H-bridge is switched directly, the output current will overshoot due to loop saturation, and stress problems will also be caused to the power devices.

[0006] It should be noted that the information disclosed above in the Background section is only intended to deepen the understanding of the overall background of the present application, and shall not be regarded as an admission or any form of suggestion that this information constitutes prior art that is publicly known to those skilled in the art; in particular, the identification of the above-mentioned problems in the prior art shall not be regarded as an admission or any form of suggestion that this information constitutes prior art that is publicly known to those skilled in the art. SUMMARY OF THE INVENTION

[0007] In view of this, the technical problem to be solved by the present invention is to provide a current source control method, apparatus, medium, processor and current source, which solves at least one of the technical problems existing in the prior art to a certain extent.

[0008] As a first aspect of the present invention, the technical solution of the embodiment of the current source control method provided by the present invention is as follows: A control method for a current source, wherein the current source can output positive current and negative current, and comprises a power tube, an H-bridge circuit, a feedback loop and a DAC module, the DAC module is configured to provide a variable reference source for the feedback loop to realize signal-level closed-loop control of the current source, the control method comprises: determining a current operating state of the current source; when the operating state is the first power-on, controlling the working sequence of the H-bridge circuit and the DAC module such that the moment when the output of the DAC module starts to be established tends to coincide with the moment when the bridge arm of the H-bridge circuit is turned on, thereby improving the response time of the output of the current source.

[0009] Further, the time required from the start of driving to the turn-on of the bridge arm of the H-bridge circuit is tr, and the time from the writing of an instruction to the start of output establishment of the DAC module is tdac, the method for controlling the working sequence of the H-bridge circuit and the DAC module is as follows: when tr≥tdac, driving the bridge arm of the H-bridge circuit is performed first, and after a first time period, writing an instruction to the DAC module is performed; when tr<tdac, writing an instruction to the DAC module is performed first, and after a second time period, driving the bridge arm of the H-bridge circuit is performed.

[0010] Optionally, the first set time is not less than tr-tdac; and / or the second set time is not less than tdac-tr.

[0011] Optionally, when the operating state is that the current source already has an output, if the output current needs to be switched according to an instruction, it is necessary to first determine the polarity relationship between the previous set current value and the current set current value, and then set the DAC code value according to the polarity relationship, so as to reduce overshoot during the switching process.

[0012] Further, the step of setting the DAC code value and performing switching according to the polarity relationship comprises: when the polarity relationship between the previously set current value and the currently set current value is consistent, the controller sets the DAC code value as the code value corresponding to the absolute value of the current current value, and executes a DAC output instruction; when the polarity relationship between the previously set current value and the currently set current value is inconsistent, the controller sets the DAC code value as the code value corresponding to 0 output current, executes the output instruction of the DAC module, after a third time, turns off the already enabled arm in the original H-bridge, and then after a fourth time, determines the timing of enabling the arm to be enabled in the H-bridge and establishing output by the DAC module, and executes a corresponding action.

[0013] Optionally, the time for the output current of the current source to drop to 0 is tif, and the time required for the arm of the H-bridge circuit from stopping driving to turning off is tf; the third time is not less than tdac+tif, and / or the fourth time is not less than tf.

[0014] Further, the step of determining the timing of enabling the arm to be enabled in the H-bridge and establishing output by the DAC module and executing a corresponding action comprises: when tr≥tdac, providing driving for the arm to be enabled first, and then executing instruction writing for the DAC module after a fifth time; when tr<tdac, executing instruction writing for the DAC module first, and then providing driving for the arm to be enabled after a sixth time.

[0015] Optionally, the fifth set time is not less than tr-tdac; and / or the sixth time is not less than tdac-tr.

[0016] As a second aspect of the present invention, the technical solution of the embodiment of the control device for a current source provided by the present invention is as follows: A control device for a current source, wherein the current source can output positive current and negative current, the current source comprises power tubes, an H-bridge circuit, a feedback loop and a DAC module, the DAC module is configured to provide a variable reference source for the feedback loop to realize signal-level closed-loop control of the current source, and the control device comprises: a judging module, configured to judge the current working state of the current source; an executing module, configured to control the working sequences of the H-bridge circuit and the DAC module when the working state is first power-on, so that the start moment of output establishment of the DAC module tends to be consistent with the enabling moment of the arms of the H-bridge circuit, thereby improving the response time of the output of the current source.

[0017] As a third aspect of the present invention, the embodiment of the computer-readable storage medium is as follows: A computer-readable storage medium comprising a stored program, wherein the program, when executed, performs the method described in any one of the first aspects above.

[0018] As a fourth aspect of the present invention, the provided embodiment of the processor is as follows: A processor, wherein the processor is configured to run a program, wherein the program, when running, performs the method described in any one of the first aspects above.

[0019] As a fifth aspect of the present invention, the technical solution of the provided current source embodiment is as follows: A current source that outputs positive and negative currents, comprising: It includes a power transistor, an H-bridge circuit, a feedback loop, and a DAC module. The DAC module is used to provide a variable reference source for the feedback loop to achieve signal-level closed-loop control of the current source. And the control device described in any of the second aspects above.

[0020] The advantages of this invention compared to the prior art are as follows: In this embodiment of the invention, when the circuit is powered on for the first time, there is a delay in the circuit. However, the time required for the H-bridge circuit arm to turn on from the start of driving and the time required for the DAC module to start establishing the output from the start of writing the instruction may be inconsistent. That is, the rise time of the H-bridge circuit arm and the DAC module turning on individually may be inconsistent. If driving is provided to the H-bridge circuit arm and writing of instructions is provided to the DAC module at the same time, it will cause the system loop to saturate, resulting in overshoot, or it will result in a long delay time. This embodiment of the invention restricts the working timing of the H-bridge circuit and the DAC module, requiring that the time when the output of the DAC module starts to establish is consistent with the time when the bridge arm of the H-bridge circuit turns on, thereby avoiding output overshoot and improving the current output response time. Attached Figure Description

[0021] Figure 1 This is a schematic block diagram of the current source of this application; Figure 2 This is a flowchart illustrating the control method of the current source of this application during the first power-on. Figure 3 This is a flowchart illustrating the control method of the current source of this application when it already has an output; Figure 4 This is a schematic block diagram of the control device for the current source of this application; Figure 5This is a schematic diagram of the control timing in the first mode of the current source; Figure 6 This is a schematic diagram of the control timing of the current source in the second mode. Detailed Implementation

[0022] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0023] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0024] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be used interchangeably where appropriate for the purposes of describing embodiments of this application herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0025] It should be understood that in the specification, claims, and drawings, when a step is described as continuing into another step, the step may directly continue into that other step or be continued into that other step through a third step; when an element / unit is described as being "connected" to another element / unit, the element / unit may be "directly connected" to that other element / unit or be "connected" to that other element / unit through a third element / unit.

[0026] Furthermore, the accompanying drawings are merely illustrative of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions thereof will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0027] In high-precision system applications, such as electron beam control systems, electron beam control is achieved by driving coils with high-precision AC current sources. Modern electron beam control systems typically require resolution at the ppm level, ultimately achieving uA-level current control. This usually necessitates the use of top-of-the-line digital-to-analog converters (ADCs) or DACs, significantly increasing their price and cost. Product performance is thus limited by the performance of the ADC or DAC.

[0028] To achieve low-cost positive and negative current output and effective output control, eliminating the need for complex power supply and positive / negative reference systems, reducing technical implementation difficulty, and improving the output current range and reliability, the principle block diagram of the current source in this application is as follows. Figure 1 As shown, it includes power transistor TR1, H-bridge circuit, feedback loop and DAC module.

[0029] The power transistor TR1 is a power device that can operate in the linear operating range. For example, the power transistor TR1 includes, but is not limited to, MOS, BJT, N-type or P-type devices. The input terminal of the power transistor TR1 is connected to the input voltage Vin, and the output terminal is connected to the input terminal of the H-bridge.

[0030] The H-bridge circuit includes a first bridge arm and a second bridge arm. The first bridge arm includes power transistors TR2 and TR4, and the second bridge arm includes power transistors TR3 and TR5. The input terminals of power transistors TR2 and TR3 are connected together to form the input terminals of the H-bridge. The output terminals of power transistors TR2 and TR4 are connected to the first node, and the output terminals of power transistors TR3 and TR5 are connected to the second node. A load is connected between the first and second nodes. The output terminals of power transistors TR4 and TR5 are connected together to form the output terminals of the H-bridge.

[0031] The feedback loop (hereinafter referred to as the "loop") includes a sampling resistor RS1, a sampling module, an analog operational amplifier U1, and a loop feedback module. The output of the H-bridge is grounded through the sampling resistor RS1. The sampling resistor RS1 has sampling points or Kelvin pins at both ends. The sampling module converts the sampled signal into a feedback signal and inputs it to the inverting input of the analog operational amplifier U1. The output of the DAC module is used to provide a variable reference source for the non-inverting input of the analog operational amplifier U1. Through the stable control of the loop feedback module, the loop output signal (i.e., the signal output by the analog operational amplifier U1) is amplified and enhanced through the driver module to drive the linear switch (i.e., the power transistor TR1), thereby realizing closed-loop control of the output current.

[0032] Figure 1The current source also includes a controller. The input to the controller is the target value of the current source output current (including polarity and absolute value), which is set as needed. The controller generates drive signals G2 to G5 according to the target value of the output current and provides instructions for writing to the DAC module. Drive signals G2 to G4 are used to drive power transistors TR2 to TR5 respectively.

[0033] The input voltage Vin passes through power transistors TR1, TR2, load, TR5, sampling resistor RS1, and ground in sequence to form a closed loop, and the resulting current is denoted as the positive current. Conversely, the input voltage Vin passes through power transistors TR1, TR3, load, TR4, sampling resistor RS1, and ground in sequence to form a closed loop, and the resulting current is the negative current. This circuit can achieve a negative load voltage without requiring an additional negative power supply input. Therefore, when the output current of the current source needs to be positive, the controller will generate drive signals G2 and G5; when the output current of the current source needs to be negative, the controller will generate drive signals G3 and G4. The absolute value of the target value of the current source output current determines the code value written by the DAC module instruction.

[0034] Since power transistor TR1 is a power device that can operate in the linear operating range, when the load current is large (and the corresponding input voltage Vin is also large), the current flowing through power transistor TR1 is also large, and the drive voltage required for power transistor TR1 is also large. However, the output voltage of analog op-amp U1 is less than or equal to its supply voltage. Therefore, the output voltage of analog op-amp U1 needs to be amplified by the drive module in order to achieve linear drive of power transistor TR1. That is, when the power supply input Vin is much greater than the supply voltage of analog op-amp U1, the output of analog op-amp U1 cannot meet the needs of driving power transistor TR1. At this time, a drive module needs to be added.

[0035] First Embodiment This embodiment provides a current source control method, applied to... Figure 1 This type of current source.

[0036] In some implementations, please refer to Figure 2 This application provides a control method for the first power-on of a current source, comprising the following steps: S101, determine the current operating status of the current source; S201, when the working state is the first power-on, control the working timing of the H-bridge circuit and the DAC module so that the time when the DAC module output starts to be established is consistent with the time when the bridge arm of the H-bridge circuit is turned on, thereby improving the response time of the current source output.

[0037] Figure 1When the current source circuit is in the working state of first power-on, due to the delay in the circuit, the time required from the start of providing driving to the turn-on of the H-bridge circuit arms may be inconsistent with the time required from the start of providing instruction writing to the start of output establishment of the DAC module, that is, the rise time of the separate turn-on of the H-bridge circuit arms and the DAC module may be inconsistent. If driving is provided for the H-bridge circuit arms and instruction writing is provided for the DAC module at the same time, it will cause system loop saturation and thus overshoot and undershoot, or result in a longer delay time. Figure 2 The control method limits the working timing of the H-bridge circuit and the DAC module, requiring that the moment when the output of the DAC module starts to be established tends to be consistent with the moment when the arms of the H-bridge circuit are turned on, thereby reducing the control delay time and improving the current output response time.

[0038] By way of example, the time required from the start of providing driving to the turn-on of the H-bridge circuit arms is tr, and the time required from the start of providing instruction writing to the start of output establishment of the DAC module is tdac. The method for controlling the working timing of the H-bridge circuit and the DAC module is as follows: When tr≥tdac, the delay time for turning on the arms is long. If the DAC module is turned on first, it will cause loop output saturation and thus overshoot. Therefore, driving is first provided for the arms of the H-bridge circuit, and after a first time period, instruction writing is performed for the DAC module; When tr<tdac, the delay time for turning on the DAC module is long. If the arms are turned on first, it will cause time delay in the whole process. Therefore, instruction writing is first performed for the DAC module, and after a second time period, driving is provided for the arms of the H-bridge circuit.

[0039] By way of example, the first set time is not less than tr-tdac.

[0040] By way of example, the second time is not less than tdac-tr.

[0041] By way of example, the first set time is not less than tr-tdac, and the second time is not less than tdac-tr.

[0042] In some embodiments, please refer to Figure 3 , the present application provides a control method when a current source has an output, comprising the following steps: S102, determining the current working state of the current source; S202, when the working state is that the current source has an output, if output current switching is required according to an instruction, it is necessary to first determine the polarity relationship between the previous set current value and the current set current value, then set the DAC code value and perform switching according to the polarity relationship, so as to reduce overshoot during the switching process.

[0043] Figure 1When a current source circuit is operating with an existing output, if it needs to switch the output current (including changing the magnitude or polarity of the output current), and the polarity of the current needs to be changed, directly switching will cause the output sampling feedback signal (i.e., ...) to be interrupted during the switching process. Figure 1 The signal output by the intermediate sampling module and the reference signal (i.e. Figure 1 If the signal output from the DAC module has too large an error, it will cause loop saturation, resulting in output overshoot. Figure 2 The control method first determines the polarity relationship between the previously set current value and the current set current value, and then sets the DAC code value and performs the switching based on the polarity relationship to reduce overshoot during the switching process.

[0044] As an example, the step of setting the DAC code value and performing the switching according to the polarity relationship in S202 above includes: When the polarity relationship between the previously set current value and the current set current value is consistent, the controller sets the DAC code value to the code value corresponding to the absolute value of the current value and executes the DAC output command. When the polarity relationship between the previously set current value and the current set current value is inconsistent, the controller sets the DAC code value to the code value corresponding to the 0 output current and executes the DAC module output command. This command, in the closed-loop control system, enables the loop output value (i.e., Figure 1 The signal output by analog operational amplifier U1 is in the initial state to avoid loop output saturation caused by direct H-bridge switching, which would lead to system instability, overshoot, or abnormalities. After the third time interval, the bridge arm that was already turned on in the original H-bridge is turned off. This timing ensures that no current flows through the bridge arm when it is turned off, thus avoiding the attraction problem caused by power transistor TR1 being in an open circuit state. After the fourth time interval, the timing of turning on the bridge arm to be turned on in the H-bridge and establishing the output of the DAC module is determined and the corresponding actions are executed.

[0045] As an example, the time it takes for the output current of the current source to drop to 0 is tif, the time required for the H-bridge circuit arm to go from stopping to turning off is tf, and the third time is not less than tdac+tif.

[0046] As an example, the time it takes for the output current of the current source to drop to 0 is tif, the time required for the H-bridge circuit arm to go from stopping providing drive to turning off is tf, and the fourth time is not less than tf.

[0047] As an example, the time for the output current of the current source to drop to 0 is tif, the time required for the H-bridge circuit arm to go from stopping to turning off is tf, the third time is not less than tdac+tif, and the fourth time is not less than tf.

[0048] By way of example, determining the sequence of turning on the arm to be turned on in the H-bridge and establishing the output of the DAC module and performing corresponding actions include: when tr≥tdac, driving is provided for the arm to be turned on first, and instruction writing is provided for the DAC module after a fifth time; when tr<tdac, instruction writing is provided for the DAC module first, and driving is provided for the arm to be turned on after a sixth time.

[0049] By way of example, the fifth set time is not less than tr-tdac.

[0050] By way of example, the sixth time is not less than tdac-tr.

[0051] By way of example, the fifth set time is not less than tr-tdac, and the sixth time is not less than tdac-tr.

[0052] Second Embodiment This embodiment provides a control device for a current source, which is applied to Figure 1 this type of current source.

[0053] In some embodiments, refer to Figure 4 , the present application provides a control device for a current source, which is applied to Figure 2 this type of current source, and includes the following modules: a judging module 100, configured to judge the current working state of the current source; an execution module 200, configured to, when the working state is first power-on, control the working sequence of the H-bridge circuit and the DAC module, so that the moment when the DAC module starts to establish output coincides with the moment when the arm of the H-bridge circuit is turned on, thereby improving the response time of the output of the current source.

[0054] Figure 4 The technical means adopted by the control device are the same as those of Figure 2 the control method, and the beneficial effects are the same, so they will not be repeated.

[0055] In addition, Figure 2 preferred technical means or further improved technical means for each step in the control method can all be extended to Figure 4 corresponding units of the control device, so they will not be described one by one in this embodiment.

[0056] In this embodiment, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative. For example, the division of the units described above can be a logical functional division; in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0057] In this embodiment, the units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0058] Furthermore, in this embodiment, the functional units in each implementation can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0059] Third Embodiment If the unit integrated into the control device in the second embodiment described above is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, read-only memory (ROM), random access memory (RAM), portable hard drive, magnetic disk, or optical disk.

[0060] Therefore, the third embodiment of the present invention provides a computer-readable storage medium, including a stored program that performs the method of any specific implementation of the first embodiment.

[0061] Fourth embodiment The fourth embodiment of the present invention provides a processor configured to run a program, wherein the program, when run, executes the method according to any one of the specific implementations in the first embodiment.

[0062] Fifth Embodiment The fifth embodiment of the present invention provides a current source that outputs positive current and negative current, comprising: a power tube, an H-bridge circuit, a feedback loop and a DAC module, wherein the DAC module is configured to provide a variable reference source for the feedback loop to implement signal-level closed-loop control of the current source; and the control device according to any one of the second embodiment described above, the specific circuit schematic diagram is as shown in Figure 1 drawings.

[0063] Exemplarily, in order to expand the current output range, improve system response, and reduce the stress of the power tube TR1, the following control method is adopted: First mode: applicable when the current source is powered on for the first time.

[0064] Figure 5 is a schematic diagram of control timing in the first mode of the current source, wherein the abscissa is time, and the ordinate is current magnitude and H-bridge enabling signal. The control steps in this mode are as follows: Step 11: determine whether the required output current is positive or negative, and confirm the bridge arm power tube that needs to be enabled.

[0065] Step 12: tr is the time required for each group of bridge arms from starting to provide driving to being enabled, tdac is the time from when the DAC module receives the instruction writing to when the output starts to be established, the control timing constraint is t1, and according to the relationship between tr and tdac, the enabling timing of the H-bridge and the DAC module is determined: When tr≥tdac, t1 is not less than tr-tdac, the bridge arm enabling instruction is executed first, after t1, the DAC instruction writing is performed, Figure 5 this is this case; When tr<tdac, t1 is not less than tdac-tr, the controller executes DAC output writing first, after t1, then executes the bridge arm enabling instruction.

[0066] This control timing compresses the delay time from DAC digital conversion to output, ensures reliable opening of the bridge arm, and can reduce the final output response time.

[0067] Second mode: applicable when the current source is already in normal operation with an existing output and needs to switch the output current according to an instruction.

[0068] Figure 5 is a schematic diagram of control timing in the second mode of the current source, wherein the abscissa is time, and the ordinate is current magnitude and H-bridge enabling signal. The control steps in this mode are as follows: Step 21: determining the polarity relationship between the previously set current value and the currently set current value.

[0069] Step 22: then setting a DAC code value and performing switching according to the polarity relationship, so as to reduce overshoot during the switching process, which is specifically as follows: when the polarity relationship between the previously set current value and the currently set current value is consistent, the controller sets the DAC code value to the code value corresponding to the absolute value of the currently set current value, and executes a DAC output instruction; when the polarity relationship between the previously set current value and the currently set current value is inconsistent, the controller sets the DAC code value to the code value corresponding to 0 output current, and executes a DAC output instruction; in a closed-loop control system, this instruction can enable the loop output value (i.e., Figure 1 the signal output by the analog operational amplifier U1 herein) to be in an initial state, avoiding loop output saturation and unstable system caused by directly performing H-bridge switching, thereby preventing system overshoot or abnormality.

[0070] Step 23: after a time t2, turning off the turned-on bridge arm in the original H-bridge. Where tif is the time required for the output current of the current source to drop to 0, tf is the time required for each group of bridge arms to turn off from stopping driving, and t2 is not less than tdac+tif; this timing can ensure that no current flows through the bridge arm when the bridge arm is turned off, and avoids the attraction problem caused by the main power linear device (i.e., the power transistor TR1) being in an open circuit state. In addition, when the output current of the current source drops to 0, the loop operational amplifier feedback signal (i.e., Figure 1 the signal output by the sampling module herein) is zero, so that the loop output (i.e., Figure 1 the signal output by the analog operational amplifier U1 herein) is zero; and at this time, the output value of the DAC module is still kept at 0, that is, both the output value of the DAC module and the loop output value are zero, which can avoid the loop saturation problem; Step 24: after a time t3, wherein t3 is not less than tf, determining the turn-on timing of the H-bridge and the DAC module according to the relationship between tr and tdac: when tr≥tdac, t4 is not less than tr-tdac, a bridge arm turn-on instruction is executed first, and after t4, a DAC output instruction is written; when tr<tdac, t4 is not less than tdac-tr, the controller executes the DAC output instruction first, and after t4, executes the bridge arm turn-on instruction; this control timing is the same as the control timing at the first power-on described above, and is also intended to improve the response time of the output current.

[0071] the beneficial effects of the above control method are summarized as follows: (1) the theoretical maximum resolution of current controlled by the traditional unipolar DAC is 1 / (2 N-1), In the above control method, since positive and negative current outputs are achieved through polarity switching, it is not necessary to increase the number of DAC bits or replace the DAC with a better one to achieve a maximum resolution of 1 / (2). （N+1） -1), which improves the output range and enhances the accuracy of the equivalent output current; (2) Based on the time from the DAC module to the output establishment from the provision of instructions and the time required for the H-bridge circuit arm to turn on from the start of the drive, adjust the conduction timing of the DAC module and the H-bridge circuit arm so that the time when the DAC module output starts to be established is consistent with the time when the H-bridge circuit arm turns on, which can improve the response time of the final output. (3) When the polarity of the output current is switched, the DAC code value is first set to the code value corresponding to the 0 output current, and then the power transistor of the bridge arm that needs to be turned off is turned off. This ensures that the H-bridge switching process is in a current-free state, eliminates the loop saturation problem caused by directly switching the H-bridge, and solves the stress problem of power transistor TR1 caused by the sudden change in current and parasitic parameters due to the direct switching of the H-bridge circuit.

[0072] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be considered as limitations on the present invention. For those skilled in the art, several equivalent substitutions, improvements, and modifications can be made without departing from the spirit and scope of the present invention. These equivalent substitutions, improvements, and modifications should also be considered within the protection scope of the present invention. Further details will not be provided here, and the protection scope of the present invention should be determined by the scope defined in the claims.

Claims

1. A control method for a current source, the current source being capable of outputting positive and negative currents, comprising a power transistor, an H-bridge circuit, a feedback loop, and a DAC module, wherein the DAC module is used to provide a variable reference source for the feedback loop to achieve signal-level closed-loop control of the current source, characterized in that... Said control method comprises: determining a current operating state of said current source; when said operating state is first power-on, controlling the operating timing of said H-bridge circuit and said DAC module, such that the moment when the output of said DAC module starts to settle and the moment when the bridge arm of said H-bridge circuit is turned on tend to coincide, thereby improving the response time of the output of said current source.

2. The control method for a current source according to claim 1, characterized in that: the time required for the bridge arm of said H-bridge circuit to turn on from the start of driving supply is tr, and the time required for said DAC module from instruction writing to the start of output settling is tdac, and the method for controlling the operating timing of said H-bridge circuit and said DAC module is as follows: when tr≥tdac, providing driving for the bridge arm of said H-bridge circuit first, and providing instruction writing for said DAC module after a first time period; when tr<tdac, providing instruction writing for said DAC module first, and providing driving for the bridge arm of said H-bridge circuit after a second time period.

3. The control method for the current source according to claim 2, characterized in that: said first set time is not less than tr-tdac; and / or said second time is not less than tdac-tr.

4. The control method for a current source according to claim 1, characterized in that: when said operating state is that said current source already has an output, if the output current needs to be switched according to an instruction, it is necessary to first determine the polarity relationship between the previous set current value and the current set current value, then set the DAC code value and perform switching according to the polarity relationship, so as to reduce overshoot during the switching process.

5. The control method for the current source according to claim 4, characterized in that, said setting the DAC code value and performing switching according to the polarity relationship comprises: when the polarity relationship between the previous set current value and the current set current value is consistent, the controller sets the DAC code value as the code value corresponding to the absolute value of the current current value, and executes a DAC output instruction; when the polarity relationship between the previous set current value and the current set current value is inconsistent, the controller sets the DAC code value as the code value corresponding to 0 output current, executes an output instruction for the DAC module, after a third time period, turns off the already turned-on bridge arm in the original H-bridge, and then after a fourth time period, determines the timing of turning on the to-be-turned-on bridge arm in the H-bridge and settling the output of the DAC module, and executes a corresponding action.

6. The control method for the current source according to claim 5, characterized in that: the time taken for the output current of said current source to drop to 0 is tif, and the time required for the bridge arm of said H-bridge circuit to turn off from stopping driving supply is tf; said third time is not less than tdac+tif, and / or said fourth time is not less than tf.

7. The control method for a current source according to claim 5, characterized in that: said determining the timing of turning on the to-be-turned-on bridge arm in the H-bridge and settling the output of the DAC module and executing a corresponding action comprises: when tr≥tdac, providing driving for said to-be-turned-on bridge arm first, and providing instruction writing for said DAC module after a fifth time period; when tr<tdac, providing instruction writing for said DAC module first, and providing driving for said to-be-turned-on bridge arm after a sixth time period.

8. The control method for the current source according to claim 7, characterized in that: The fifth set time is not less than tr-tdac; and / or the sixth time is not less than tdac-tr.

9. A control device for a current source, the current source being capable of outputting positive and negative currents, comprising a power transistor, an H-bridge circuit, a feedback loop, and a DAC module, wherein the DAC module is used to provide a variable reference source to the feedback loop to achieve signal-level closed-loop control of the current source, characterized in that... The control device includes: The judgment module is configured to determine the current operating state of the current source; The execution module is configured to control the timing of the H-bridge circuit and the DAC module when the operating state is the first power-on, so that the time when the output of the DAC module starts to be established is consistent with the time when the bridge arm of the H-bridge circuit is turned on, thereby improving the response time of the current source output.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored program, wherein the program, when executed, performs the method according to any one of claims 1 to 8.

11. A processor, characterized in that, The processor is used to run a program, wherein the program executes the method according to any one of claims 1 to 8 when it runs.

12. A current source that outputs positive current and negative current, characterized in that, include: It includes a power transistor, an H-bridge circuit, a feedback loop, and a DAC module. The DAC module is used to provide a variable reference source for the feedback loop to achieve signal-level closed-loop control of the current source. And the control device as described in claim 9.

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