A current control circuit for an EFO

Abstract

The application relates to the technical field of semiconductor production, and discloses a current control circuit for EFO, which comprises an external control module, a controlled mirror constant current source module, a current coarse adjustment module and a high-speed DA analog output module; wherein the high-speed DA analog output module, the controlled mirror constant current source module and the external control module are sequentially connected; and the current coarse adjustment module is connected with the controlled mirror constant current source module and the external control module respectively. The current control circuit for EFO provided by the application can automatically and widely adjust the current through the use of the current coarse adjustment module, and can automatically and steplessly adjust the maximum current limit through the use of the controlled mirror constant current source module, which is beneficial to the EFO control of the discharge current, thereby controlling the ball burning effect, and is worth promoting.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to a current control circuit for an EFO. Background Technology

[0002] Wire bonding machines, as core equipment in semiconductor packaging, play an important role in sub-sectors such as optical communication, sensor industry, military industry, and power semiconductor.

[0003] The burning status of the EFO (Electronic Flame Off) in a wire bonding machine has a significant impact on the welding quality, and one of the most important functions of the EFO is to control the discharge current, thereby controlling the burning effect.

[0004] Currently, because EFOs need to maintain the arc, the VCC is generally quite high, typically around 700V to 1500V. Traditional EFO current control uses voltage-controlled constant current sources composed of operational amplifiers and MOSFETs (including EPD-1000, 207HV, kns, Xiangyou, etc.). This leads to a problem: current accuracy and current range are not simultaneously compatible (if a small current is used, most of the power will be absorbed by the constant current MOSFET, and the MOSFET itself has a maximum power limit). Therefore, either the maximum discharge current is limited (mostly within 150mA), or a segmented control is used by adding switches (limiting the maximum current by changing the resistance in the circuit, thus sharing the power) to achieve a wide current range (0-300mA).

[0005] However, the aforementioned maximum current limiting schemes may not be sufficient for some specialized applications (such as certain thicker platinum wires). The segmented control scheme, when achieving a wide range of control, may be difficult to handle if the operating current happens to be near the dividing point between the two current segments. Using a smaller current level may result in failure to meet process requirements and failure to burn the wires, while using a larger current level may lead to increased power consumption of the constant current MOS, increased MOS temperature, and increased EMI.

[0006] Therefore, improvements to existing technologies are necessary.

[0007] The above information is provided as background information only to aid in understanding this disclosure and does not constitute an assertion or admission that any of the above content can be used as prior art relative to this disclosure. Summary of the Invention

[0008] This invention provides a current control circuit for an EFO to solve the problems existing in the prior art.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] A current control circuit for an EFO includes an external control module, a controlled mirror constant current source module, a current coarse adjustment module, and a high-speed DA analog output module; wherein,

[0011] The high-speed DA analog output module, the controlled mirror constant current source module, and the external control module are connected in sequence.

[0012] The current coarse adjustment module is connected to the controlled mirror constant current source module and the external control module, respectively.

[0013] Furthermore, in the current control circuit for EFO, the controlled mirror constant current source module includes a dual-channel transistor Q5, a first operational amplifier U1, a second MOSFET T2, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4.

[0014] The base of the first-stage diode in the dual-channel transistor Q5 is connected to the base of the second-stage diode.

[0015] The emitter of the first-stage diode is connected to the inverting input terminal of the first operational amplifier U1, and the collector of the first-stage diode is connected to the source of the second MOSFET T2.

[0016] The collector of the second-stage diode is connected to the current coarse adjustment module;

[0017] The gate of the second MOSFET T2 is connected to the output terminal of the first operational amplifier U1;

[0018] The non-inverting input of the first operational amplifier U1 is connected to the high-speed DA analog output module;

[0019] The first resistor R1 and the second resistor R2 are connected in parallel, with one end connected to the emitter of the first-stage diode and the other end grounded.

[0020] The third resistor R3 and the fourth resistor R4 are connected in parallel, with one end connected to the emitter of the second-stage diode and the other end grounded.

[0021] Furthermore, in the current control circuit for EFO, the first-stage diode and the second-stage diode are located in the same package structure.

[0022] Furthermore, in the current control circuit for EFO, the current coarse adjustment module includes a first MOSFET T1, a voltage follower U2, an adder circuit, and a damping circuit.

[0023] The source of the first MOSFET T1 is connected to the collector of the second-stage diode, and the gate of the first MOSFET T1 is connected to the external control module.

[0024] The non-inverting input of the voltage follower U2 is connected to the non-inverting input of the first operational amplifier U1, the inverting input of the voltage follower U2 is connected to the output of the voltage follower U2, and the output of the voltage follower U2 is connected to the adder circuit.

[0025] The damping circuit is connected to both the adding circuit and the external control module.

[0026] Furthermore, in the current control circuit for EFO, the adder circuit includes a second operational amplifier U3, a fifth resistor R5, a sixth resistor R6, and a first diode D1;

[0027] One end of the fifth resistor R5 is connected to the output terminal of the voltage follower U2, and the other end is connected to the non-inverting input terminal of the second operational amplifier U3;

[0028] The positive terminal of the first diode D1 is grounded, and the negative terminal of the first diode D1 is connected to the power supply voltage VCC.

[0029] One end of the sixth resistor R6 is connected to the non-inverting input terminal of the second operational amplifier U3, and the other end is connected to the negative terminal of the first diode D1;

[0030] The inverting input and output terminals of the second operational amplifier U3 are respectively connected to the damping circuit.

[0031] Furthermore, in the current control circuit for EFO, the damping circuit includes a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a first capacitor C1, and a second capacitor C2.

[0032] One end of the ninth resistor R9 is connected to the inverting input terminal of the second operational amplifier U3, and the other end is grounded;

[0033] One end of the seventh resistor R7 is connected to the output terminal of the second operational amplifier U3, and the other end is connected to the external control module;

[0034] The eighth resistor R8 and the first capacitor C1 are connected in parallel. One end of the connection is connected to the inverting input terminal of the second operational amplifier U3, and the other end is connected between the seventh resistor R7 and the external control module.

[0035] The tenth resistor R10 and the second capacitor C2 are connected in parallel, with one end connected between the seventh resistor R7 and the external control module, and the other end grounded.

[0036] Furthermore, in the current control circuit for EFO, the high-speed DA analog output module includes a DA chip U4 and a third operational amplifier U5;

[0037] The IOUT pin of the DA chip is connected to the non-inverting input of the third operational amplifier U5, and the RFFB pin of the DA chip is connected to the output of the third operational amplifier U5.

[0038] The inverting input terminal of the third operational amplifier U5 is grounded, and the output terminal of the third operational amplifier U5 is connected to the non-inverting input terminal of the first operational amplifier U1.

[0039] Furthermore, in the current control circuit for EFO, the external control module includes a third MOSFET T3, a fourth MOSFET T4, a fifth MOSFET T5, an eleventh resistor R11, a twelfth resistor R12, a second diode D2, a third capacitor C3, and an optocoupler U6.

[0040] The source of the third MOS transistor T3 is connected to the gate of the first MOS transistor T1, the gate of the third MOS transistor T3 is connected to the gate of the fifth MOS transistor T5, and the drain of the third MOS transistor T3 is connected to the seventh resistor R1.

[0041] The drain of the fifth MOS transistor T5 is connected to the gate of the first MOS transistor T1, the source of the fifth MOS transistor T5 is grounded, and the gate of the fifth MOS transistor T5 is connected to the drain of the fourth MOS transistor T4.

[0042] The drain of the fourth MOSFET T4 is connected to the power supply voltage VCC through the eleventh resistor R11, and the source of the fourth MOSFET T4 is grounded.

[0043] The cathode of the second diode D2 is connected to the gate of the fourth MOSFET T4, and the anode of the second diode D2 is connected to the optocoupler U6.

[0044] The twelfth resistor R12 is connected in parallel across the second diode D2;

[0045] One end of the third capacitor C3 is connected between the negative terminal of the second diode D2 and the gate of the fourth MOSFET T4, and the other end is grounded;

[0046] The optocoupler U6 is connected to the control terminal.

[0047] Furthermore, in the current control circuit for EFO, the optocoupler includes a light-emitting diode and a phototransistor;

[0048] The collector of the phototransistor is connected to the positive terminal of the second diode D2, the emitter of the phototransistor is grounded, and the base of the phototransistor is connected to the power supply voltage VCC.

[0049] The negative terminal of the LED is grounded, and the positive terminal of the LED is connected to the control terminal.

[0050] Furthermore, in the current control circuit for EFO, both the first-stage diode and the second-stage diode are high-gain transistors.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] This invention provides a current control circuit for an EFO (Electronic Focal Optimizer), comprising an external control module, a controlled mirror constant current source module, and a high-speed DA analog output module connected in sequence, and a current coarse adjustment module connected to the controlled mirror constant current source module and the external control module respectively. By using the current coarse adjustment module, the current can be automatically adjusted over a wide range according to the input. Furthermore, due to the use of the controlled mirror constant current source module, the maximum current limit can be automatically and steplessly adjusted, which is beneficial for controlling the discharge current of the EFO and thus controlling the ball burning effect. This invention is worthy of promotion.

[0053] The present invention has other features and advantages, which will be apparent from or will be set forth in detail in the accompanying drawings and the following detailed description, which together serve to explain the particular principles of the invention. Attached Figure Description

[0054] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0055] Figure 1 This is a schematic diagram of the circuit principle of a conventional constant current source;

[0056] Figure 2 This is a schematic diagram of the circuit principle of a segmented constant current source;

[0057] Figure 3 It is a process diagram for segmented current;

[0058] Figure 4 This is a schematic diagram of the circuit principle of a current control circuit for an EFO provided in an embodiment of the present invention;

[0059] Figure 5 This is a schematic diagram of the circuit principle of a current control circuit for an EFO provided in an embodiment of the present invention;

[0060] Figure 6 This is a schematic diagram of the output characteristic curve of the MOS transistor provided in an embodiment of the present invention. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Furthermore, those skilled in the art will understand that with technological development and the emergence of new scenarios, the technical solutions provided by the embodiments of this application are also applicable to similar technical problems.

[0062] In the description of this application, it should be understood that, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. Furthermore, any terminology used is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0063] Furthermore, to better illustrate this application, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that this application can be implemented without certain specific details. In some instances, methods, means, components, and circuits well-known to those skilled in the art have not been described in detail in order to highlight the main points of this application.

[0064] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0065] Example 1

[0066] Please refer to Figure 1 , Figure 1 This is a schematic diagram of a conventional constant current source circuit. The working principle of a conventional constant current source is explained below:

[0067] By utilizing the negative feedback principle of the op-amp, the voltages at the non-inverting and inverting terminals of the op-amp are made to be the same. Then, the load current is calculated as I = Vin / R300. If VCC is a very high voltage source, then the MOSFET Q will receive a large amount of power. Since MOSFET Q has a maximum power parameter, exceeding the rated power will cause the MOSFET Q to burn out.

[0068] Please refer to Figure 2 , Figure 2 This is a schematic diagram of the circuit principle of a segmented constant current source. The working principle of the segmented constant current source is explained below:

[0069] The segmented constant current source is designed to prevent the power of the MOSFET Q from being overloaded in a conventional constant current source. The specific working principle is to control the maximum load current through MOSFETs Q1, Q2, and Q3, thereby sharing the power on MOSFET Q4 and correcting the problems that occur in conventional constant current sources.

[0070] The process diagram for segmented current is as follows: Figure 3 As shown. Segmented ball-burning current process description:

[0071] The gold wire is melted by the high temperature generated by the electric arc. Under the influence of gravity and tension, the molten metal solidifies into a spherical shape. In order to prevent the formation of "golf balls" (not round balls, but stars that deviate from the metal wire), the process often uses a multi-segment current process, that is, controlling the current magnitude at different times, thereby controlling the impact of the electric arc temperature on the burning ball. Using segmented current can produce a more suitable spherical shape.

[0072] As can be seen, the current will change. If the changing current happens to be at both ends of the segmented current dividing point, the problem described earlier will occur. For example, if a3 is the segmented current dividing point, then a1 needs to use a small current level, and a2 needs to use a large current level.

[0073] Although the lower gear can be switched to the higher gear at time t2, there is a risk of contention, which may cause excessive power consumption of the MOSFET. In addition, because the entire system requires extremely high precision, at the microsecond level, there is a possibility that the current may not rise to the set value in time due to insufficient switching of the current-limiting MOSFET.

[0074] In view of the deficiencies in the existing technology, the applicant, based on years of practical experience and professional knowledge in the design and manufacture of such products, and in conjunction with the application of theoretical principles, actively conducted research and innovation in order to create a technology that could solve the deficiencies in the existing technology. After continuous research, design, and repeated prototype production and improvement, the present invention, which has practical value, was finally created.

[0075] Please refer to Figure 4 This invention provides a current control circuit for an EFO, including an external control module, a controlled mirror constant current source module, a current coarse adjustment module, and a high-speed DA analog output module; wherein,

[0076] The high-speed DA analog output module, the controlled mirror constant current source module, and the external control module are connected in sequence.

[0077] The current coarse adjustment module is connected to the controlled mirror constant current source module and the external control module, respectively.

[0078] It should be noted that this embodiment uses a novel current control method, proposing a solution that can achieve a wide range of current coverage and automatically and steplessly adjust the maximum current limit, thus avoiding the drawbacks of the segmented control mentioned above.

[0079] Specifically, by using a current coarse adjustment module, the current can be automatically adjusted over a wide range according to the input. Furthermore, by using a controlled mirror constant current source module, the maximum current limit can be automatically and steplessly adjusted, which is beneficial for EFO to control the discharge current and thus control the ball burning effect.

[0080] Please refer to Figure 5 In this embodiment, the controlled mirror constant current source module includes a dual-channel transistor Q5, a first operational amplifier U1, a second MOSFET T2, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4.

[0081] The base of the first-stage diode in the dual-channel transistor Q5 is connected to the base of the second-stage diode.

[0082] The emitter of the first-stage diode is connected to the inverting input terminal of the first operational amplifier U1, and the collector of the first-stage diode is connected to the source of the second MOSFET T2.

[0083] The collector of the second-stage diode is connected to the current coarse adjustment module;

[0084] The gate of the second MOSFET T2 is connected to the output terminal of the first operational amplifier U1;

[0085] The non-inverting input of the first operational amplifier U1 is connected to the high-speed DA analog output module;

[0086] The first resistor R1 and the second resistor R2 are connected in parallel, with one end connected to the emitter of the first-stage diode and the other end grounded.

[0087] The third resistor R3 and the fourth resistor R4 are connected in parallel, with one end connected to the emitter of the second-stage diode and the other end grounded.

[0088] It should be noted that the controlled mirror constant current source module in this embodiment incorporates all the advantages of a mirror constant current source, exhibiting good stability. The key components of a mirror constant current source are two transistors (i.e., the first-stage diode and the second-stage diode). As is well known, semiconductor components can exhibit slight variations between different individuals, and these variations may lead to incomplete mirroring in the mirror constant current source. This embodiment uses the first-stage diode and the second-stage diode located within the same package structure, thus minimizing performance differences caused by variations in transistor parameters. Because they are within the same package structure, the impact of temperature rise on both ends of the mirror is nearly identical, minimizing the influence of temperature on the system.

[0089] The controlled mirror constant current source module also relies on the negative feedback of the operational amplifier to complete the current closed loop and control. The mirror constant current source can ensure that the two output currents are approximately equal.

[0090] The innovation of this embodiment lies in the use of the controlled mirror constant current source module, and the addition of some extra circuits on the output side to achieve automatic stepless adjustment.

[0091] Please refer to this again. Figure 5 In this embodiment, the current coarse adjustment module includes a first MOSFET T1, a voltage follower U2, an adder circuit, and a damping circuit;

[0092] The source of the first MOSFET T1 is connected to the collector of the second-stage diode, and the gate of the first MOSFET T1 is connected to the external control module.

[0093] The non-inverting input of the voltage follower U2 is connected to the non-inverting input of the first operational amplifier U1, the inverting input of the voltage follower U2 is connected to the output of the voltage follower U2, and the output of the voltage follower U2 is connected to the adder circuit.

[0094] The damping circuit is connected to both the adding circuit and the external control module.

[0095] It should be noted that the first MOSFET T1 functions similarly to the MOG transistors Q1, Q2, and Q3 in the segmented constant current source, sharing the power. However, the difference is that it does not require an additional control pin, has no critical point interference, and can automatically and coarsely adjust. The voltage follower U2 follows the input signal to achieve impedance matching, while the purpose of the adder circuit is to provide bias so that the first MOSFET T1 operates in the constant current region. (In the constant current region, the current hardly changes with the VDS voltage, so the first MOSFET T1 can be considered an open-loop constant current source with relatively low precision, and can be called a coarse-adjustment MOSFET.)

[0096] The output of the adder circuit is damped to stabilize the output and prevent short circuits. In addition, the coarse adjustment MOS is controlled by other signals and can be turned off at any time, forming a protection function together with other modules in the EFO.

[0097] Because a coarse current adjustment module is used, firstly, it achieves automatic, wide-range adjustment based on input; secondly, since only coarse current adjustment is implemented, precision requirements are almost nonexistent, and the impact of the coarse-adjusted MOSFET on the current after adjustment—whether it shares power or not, or whether it heats up—is irrelevant. The precise ignition current is achieved through the fine adjustment of the second-stage mirror constant current source. Because the second-stage current adjustment uses two transistors in the same package, temperature sensitivity is significantly reduced. Furthermore, the use of high-gain transistors ensures that the current at the mirror output is nearly equal to the current at the mirror input.

[0098] Please refer to this again. Figure 5 In this embodiment, the adder circuit includes a second operational amplifier U3, a fifth resistor R5, a sixth resistor R6, and a first diode D1;

[0099] One end of the fifth resistor R5 is connected to the output terminal of the voltage follower U2, and the other end is connected to the non-inverting input terminal of the second operational amplifier U3;

[0100] The positive terminal of the first diode D1 is grounded, and the negative terminal of the first diode D1 is connected to the power supply voltage VCC.

[0101] One end of the sixth resistor R6 is connected to the non-inverting input terminal of the second operational amplifier U3, and the other end is connected to the negative terminal of the first diode D1;

[0102] The inverting input and output terminals of the second operational amplifier U3 are respectively connected to the damping circuit.

[0103] Please refer to this again. Figure 5 In this embodiment, the damping circuit includes a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a first capacitor C1, and a second capacitor C2.

[0104] One end of the ninth resistor R9 is connected to the inverting input terminal of the second operational amplifier U3, and the other end is grounded;

[0105] One end of the seventh resistor R7 is connected to the output terminal of the second operational amplifier U3, and the other end is connected to the external control module;

[0106] The eighth resistor R8 and the first capacitor C1 are connected in parallel. One end of the connection is connected to the inverting input terminal of the second operational amplifier U3, and the other end is connected between the seventh resistor R7 and the external control module.

[0107] The tenth resistor R10 and the second capacitor C2 are connected in parallel, with one end connected between the seventh resistor R7 and the external control module, and the other end grounded.

[0108] It should be noted that the damping circuit can stabilize the output of the second operational amplifier U3 and prevent the output of the module from being short-circuited. At the same time, it forms a voltage tracking circuit through the negative feedback resistor (i.e., the eighth resistor R8) to ensure the voltage accuracy here.

[0109] Please refer to this again. Figure 5 In this embodiment, the high-speed DA analog output module includes a DA chip U4 and a third operational amplifier U5;

[0110] The IOUT pin of the DA chip is connected to the non-inverting input of the third operational amplifier U5, and the RFFB pin of the DA chip is connected to the output of the third operational amplifier U5.

[0111] The inverting input terminal of the third operational amplifier U5 is grounded, and the output terminal of the third operational amplifier U5 is connected to the non-inverting input terminal of the first operational amplifier U1.

[0112] It should be noted that the controller can send signals to change the output voltage of the high-speed DA analog output module at any time.

[0113] Please refer to this again. Figure 5 In this embodiment, the external control module includes a third MOSFET T3, a fourth MOSFET T4, a fifth MOSFET T5, an eleventh resistor R11, a twelfth resistor R12, a second diode D2, a third capacitor C3, and an optocoupler U6.

[0114] The source of the third MOS transistor T3 is connected to the gate of the first MOS transistor T1, the gate of the third MOS transistor T3 is connected to the gate of the fifth MOS transistor T5, and the drain of the third MOS transistor T3 is connected to the seventh resistor R1.

[0115] The drain of the fifth MOS transistor T5 is connected to the gate of the first MOS transistor T1, the source of the fifth MOS transistor T5 is grounded, and the gate of the fifth MOS transistor T5 is connected to the drain of the fourth MOS transistor T4.

[0116] The drain of the fourth MOSFET T4 is connected to the power supply voltage VCC through the eleventh resistor R11, and the source of the fourth MOSFET T4 is grounded.

[0117] The cathode of the second diode D2 is connected to the gate of the fourth MOSFET T4, and the anode of the second diode D2 is connected to the optocoupler U6.

[0118] The twelfth resistor R12 is connected in parallel across the second diode D2;

[0119] One end of the third capacitor C3 is connected between the negative terminal of the second diode D2 and the gate of the fourth MOSFET T4, and the other end is grounded;

[0120] The optocoupler U6 is connected to the control terminal.

[0121] It should be noted that the external control module can mainly control the output and cutoff of the mirror constant current source output path (left side) through external signals, and the protection circuit module can perform protection functions by controlling this signal.

[0122] The dual-channel transistor Q5 will precisely adjust the coarsely adjusted current, meaning that the first MOSFET T1 will share a lot of power so that the dual-channel transistor Q5 will not burn out from bearing all the power.

[0123] Please refer to this again. Figure 5 In this embodiment, the optocoupler includes a light-emitting diode and a phototransistor;

[0124] The collector of the phototransistor is connected to the positive terminal of the second diode D2, the emitter of the phototransistor is grounded, and the base of the phototransistor is connected to the power supply voltage VCC.

[0125] The negative terminal of the LED is grounded, and the positive terminal of the LED is connected to the control terminal.

[0126] The output characteristic curve of the MOSFET is as follows Figure 6 As shown.

[0127] Although this application frequently uses terms such as external control module, controlled mirror constant current source module, current coarse adjustment module, and high-speed DA analog output module, the possibility of using other terms is not excluded. These terms are used merely for the convenience of describing and explaining the essence of the invention; interpreting them as any additional limitation would contradict the spirit of the invention.

[0128] This invention provides a current control circuit for an EFO (Electronic Focal Optimizer), comprising an external control module, a controlled mirror constant current source module, and a high-speed DA analog output module connected in sequence, and a current coarse adjustment module connected to the controlled mirror constant current source module and the external control module respectively. By using the current coarse adjustment module, the current can be automatically adjusted over a wide range according to the input. Furthermore, due to the use of the controlled mirror constant current source module, the maximum current limit can be automatically and steplessly adjusted, which is beneficial for controlling the discharge current of the EFO and thus controlling the ball burning effect. This invention is worthy of promotion.

[0129] In summary, after reading this detailed disclosure, those skilled in the art will understand that the foregoing detailed disclosure is presented by way of example only and is not restrictive. Although not explicitly stated herein, those skilled in the art will understand that this application is intended to encompass various reasonable changes, improvements, and modifications to the embodiments. These changes, improvements, and modifications are intended to be made by this application and are within the spirit and scope of the exemplary embodiments of this application.

[0130] Furthermore, certain terms used in this application have been used to describe embodiments of this application. For example, "an embodiment," "an embodiment," and / or "some embodiments" mean that a particular feature, structure, or characteristic described in connection with that embodiment may be included in at least one embodiment of this application. Therefore, it is to be emphasized and understood that two or more references to "an embodiment" or "an embodiment" or "an alternative embodiment" in various parts of this specification do not necessarily refer to the same embodiment. Moreover, specific features, structures, or characteristics may be appropriately combined in one or more embodiments of this application.

[0131] It should be understood that in the foregoing description of the embodiments of this application, various features are combined in a single embodiment, drawing, or description for the purpose of simplifying the understanding of a feature. However, this does not mean that the combination of these features is necessary, and those skilled in the art may extract some features as separate embodiments when reading this application. That is, the embodiments in this application can also be understood as an integration of multiple sub-embodiments. It is also valid when the content of each sub-embodiment contains fewer than all the features of a single foregoing disclosed embodiment.

[0132] Finally, it should be understood that the embodiments disclosed herein are illustrative of the principles of the embodiments of this application. Other modified embodiments are also within the scope of this application. Therefore, the embodiments disclosed herein are merely examples and not limitations. Those skilled in the art can adopt alternative configurations to implement the applications in this application based on the embodiments in this application. Therefore, the embodiments of this application are not limited to the embodiments precisely described in the application.

Claims

1. A current control circuit for an EFO, characterized in that, It includes an external control module, a controlled mirror constant current source module, a current coarse adjustment module, and a high-speed DA analog output module; among which, The high-speed DA analog output module, the controlled mirror constant current source module, and the external control module are connected in sequence. The current coarse adjustment module is connected to the controlled mirror constant current source module and the external control module, respectively. The controlled mirror constant current source module includes a dual-channel transistor Q5, a first operational amplifier U1, a second MOSFET T2, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4; The base of the first-stage diode in the dual-channel transistor Q5 is connected to the base of the second-stage diode. The emitter of the first-stage diode is connected to the inverting input terminal of the first operational amplifier U1, and the collector of the first-stage diode is connected to the source of the second MOSFET T2. The collector of the second-stage diode is connected to the current coarse adjustment module; The gate of the second MOSFET T2 is connected to the output terminal of the first operational amplifier U1; The non-inverting input of the first operational amplifier U1 is connected to the high-speed DA analog output module; The first resistor R1 and the second resistor R2 are connected in parallel, with one end connected to the emitter of the first-stage diode and the other end grounded. The third resistor R3 and the fourth resistor R4 are connected in parallel, with one end connected to the emitter of the second-stage diode and the other end grounded. The first-stage diode and the second-stage diode are located in the same package structure; The current coarse adjustment module includes a first MOSFET T1, a voltage follower U2, an adder circuit, and a damping circuit. The source of the first MOSFET T1 is connected to the collector of the second-stage diode, and the gate of the first MOSFET T1 is connected to the external control module. The non-inverting input of the voltage follower U2 is connected to the non-inverting input of the first operational amplifier U1, the inverting input of the voltage follower U2 is connected to the output of the voltage follower U2, and the output of the voltage follower U2 is connected to the adder circuit. The damping circuit is connected to both the adding circuit and the external control module. The drain of the first MOSFET T1 is connected to the load; The drain of the second MOSFET T2 is connected to the positive power supply voltage.

2. The current control circuit for EFO according to claim 1, characterized in that, The adder circuit includes a second operational amplifier U3, a fifth resistor R5, a sixth resistor R6, and a first diode D1; One end of the fifth resistor R5 is connected to the output terminal of the voltage follower U2, and the other end is connected to the non-inverting input terminal of the second operational amplifier U3; The positive terminal of the first diode D1 is grounded, and the negative terminal of the first diode D1 is connected to the power supply voltage VCC. One end of the sixth resistor R6 is connected to the non-inverting input terminal of the second operational amplifier U3, and the other end is connected to the negative terminal of the first diode D1; The inverting input and output terminals of the second operational amplifier U3 are respectively connected to the damping circuit.

3. The current control circuit for EFO according to claim 2, characterized in that, The damping circuit includes a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a first capacitor C1, and a second capacitor C2. One end of the ninth resistor R9 is connected to the inverting input terminal of the second operational amplifier U3, and the other end is grounded; One end of the seventh resistor R7 is connected to the output terminal of the second operational amplifier U3, and the other end is connected to the external control module; The eighth resistor R8 and the first capacitor C1 are connected in parallel. One end of the connection is connected to the inverting input terminal of the second operational amplifier U3, and the other end is connected between the seventh resistor R7 and the external control module. The tenth resistor R10 and the second capacitor C2 are connected in parallel, with one end connected between the seventh resistor R7 and the external control module, and the other end grounded.

4. The current control circuit for EFO according to claim 3, characterized in that, The high-speed DA analog output module includes a DA chip U4 and a third operational amplifier U5; The IOUT pin of the DA chip is connected to the non-inverting input of the third operational amplifier U5, and the RFFB pin of the DA chip is connected to the output of the third operational amplifier U5. The inverting input terminal of the third operational amplifier U5 is grounded, and the output terminal of the third operational amplifier U5 is connected to the non-inverting input terminal of the first operational amplifier U1.

5. The current control circuit for EFO according to claim 4, characterized in that, The external control module includes a third MOSFET T3, a fourth MOSFET T4, a fifth MOSFET T5, an eleventh resistor R11, a twelfth resistor R12, a second diode D2, a third capacitor C3, and an optocoupler U6. The source of the third MOS transistor T3 is connected to the gate of the first MOS transistor T1, the gate of the third MOS transistor T3 is connected to the gate of the fifth MOS transistor T5, and the drain of the third MOS transistor T3 is connected to the seventh resistor R1. The drain of the fifth MOS transistor T5 is connected to the gate of the first MOS transistor T1, the source of the fifth MOS transistor T5 is grounded, and the gate of the fifth MOS transistor T5 is connected to the drain of the fourth MOS transistor T4. The drain of the fourth MOSFET T4 is connected to the power supply voltage VCC through the eleventh resistor R11, and the source of the fourth MOSFET T4 is grounded. The cathode of the second diode D2 is connected to the gate of the fourth MOSFET T4, and the anode of the second diode D2 is connected to the optocoupler U6. The twelfth resistor R12 is connected in parallel across the second diode D2; One end of the third capacitor C3 is connected between the negative terminal of the second diode D2 and the gate of the fourth MOSFET T4, and the other end is grounded; The optocoupler U6 is connected to the control terminal.

6. The current control circuit for EFO according to claim 5, characterized in that, The optocoupler includes a light-emitting diode and a phototransistor; The collector of the phototransistor is connected to the positive terminal of the second diode D2, the emitter of the phototransistor is grounded, and the base of the phototransistor is connected to the power supply voltage VCC. The negative terminal of the LED is grounded, and the positive terminal of the LED is connected to the control terminal.

7. The current control circuit for EFO according to claim 1, characterized in that, Both the first-stage diode and the second-stage diode are high-gain transistors.

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