Constant current driving system

Abstract

The invention provides a constant-current driving system, and belongs to the technical field of current driving, the system comprises a terminal and a constant-current driving circuit which are electrically connected with each other, the constant-current driving circuit comprises an MCU circuit, a first operational amplifier, a second operational amplifier, a third operational amplifier, a precision amplifier and a DC-DC power supply circuit, the terminal is connected with the input end of the MCU circuit, and the terminal is connected with the input end of the precision amplifier. The output end of the MCU circuit is connected with the positive input end of the first operational amplifier, the output end of the first operational amplifier is connected with the inverted input end of the second operational amplifier, the output end of the second operational amplifier is connected with the inverted input end of the third operational amplifier, and the output end of the second operational amplifier is further connected with the precision amplifier. The output end of the third operational amplifier is connected with the DC-DC power supply circuit, one end of the laser is connected with the precision amplifier, and the other end of the laser is connected with the DC-DC power supply circuit.

Description

Technical Field

[0001] The present invention relates to the technical field of current driving, and in particular to a constant current driving system. Background Art

[0002] Semiconductor lasers, also known as laser diodes (LD), are currently widely used in laser ranging, laser marking, laser radar, laser communication, laser simulation weapons, optoelectronic information processing, medical military, testing instruments and other fields.

[0003] Semiconductor lasers rely on direct carrier injection to work. The stability of the injected current has a direct and obvious impact on the output of the laser. Therefore, the driving technology of semiconductor lasers usually adopts a constant current drive method, which usually requires high output current stability, small surge current and small ripple.

[0004] There are already some mature solutions for conventional laser constant current drive systems on the market. However, these drive circuits are generally only suitable for lasers with specific PVI (power-voltage-current). Replacing lasers with different parameters often requires changing or redesigning the circuit, otherwise the system efficiency and stability are low. Therefore, there are technical problems in the prior art that the constant current drive system has low adaptability to different types of lasers, poor stability and low precision. Summary of the invention

[0005] In view of this, it is necessary to provide a constant current driving system to solve the technical problems of low adaptability, poor stability and low precision of the constant current driving system in the prior art to lasers of different models.

[0006] In order to solve the above technical problems, the present invention provides a constant current driving system for driving a laser, the system comprising terminals electrically connected to each other and a constant current driving circuit: The constant current drive circuit includes an MCU circuit, a first operational amplifier, a second operational amplifier, a third operational amplifier, a precision amplifier and a DC-DC power supply circuit; Wherein, the terminal is connected to the input terminal of the MCU circuit; The output terminal of the MCU circuit is connected to the positive input terminal of the first operational amplifier; The output terminal of the first operational amplifier is connected to the inverting input terminal of the second operational amplifier; The output terminal of the second operational amplifier is connected to the inverting input terminal of the third operational amplifier; The output terminal of the second operational amplifier is also connected to the precision amplifier; The output terminal of the third operational amplifier is connected to the DC-DC power supply circuit; One end of the laser is connected to a precision amplifier, and the other end of the laser is connected to a DC-DC power supply circuit; The terminal is used to obtain external input laser data to be matched, and compare the model based on the laser data to be matched and the pre-stored model data to obtain a comparison result, and generate a control instruction based on the comparison result; the laser data is: power, voltage and current of the laser; The MCU circuit is used to perform constant current driving after receiving the control instruction.

[0007] In a possible implementation, the terminal is connected to the MCU circuit, including: The terminal is connected to the MCU circuit via SPI.

[0008] In a possible implementation, the circuit further includes: a first resistor; and the output terminal of the first operational amplifier is connected to the inverting input terminal of the second operational amplifier through the first resistor.

[0009] In a possible implementation, the circuit further includes: a second resistor; one end of the second resistor is connected to the positive input end of the second operational amplifier, and the other end of the second resistor is grounded.

[0010] In a possible implementation, the circuit further includes: a third resistor; one end of the third resistor is connected to the inverting input end of the second operational amplifier, and the other end of the third resistor is connected to the output end of the second operational amplifier.

[0011] In a possible implementation, the circuit further includes: a fourth resistor, a fifth resistor, and a sixth resistor; The fourth resistor, the fifth resistor and the sixth resistor intersect at one point; One end of the fourth resistor is connected to the output end of the second operational amplifier; One end of the fifth resistor is grounded; One end of the sixth resistor is connected to the precision amplifier.

[0012] In a possible implementation, the circuit further includes: a sampling resistor; the sampling resistor is connected in parallel with the precision amplifier.

[0013] In a possible implementation, the circuit further includes: a capacitor; One end of the capacitor intersects with the inverting input terminal of the third operational amplifier, the fourth resistor, the fifth resistor and the sixth resistor at a point; The other end of the capacitor is connected to the output end of the third operational amplifier.

[0014] In a possible implementation, the circuit further includes: a seventh resistor; one end of the seventh resistor is grounded, and the other end of the seventh resistor is connected to the positive input terminal of the third operational amplifier.

[0015] In a possible implementation, the circuit further includes: an eighth resistor and a MOS tube; One end of the eighth resistor is connected to the output end of the third operational amplifier, and the other end of the eighth resistor is connected to the MOS tube; The other end of the MOS tube is connected to the laser, and the third end of the MOS tube is also connected to the precision amplifier.

[0016] The beneficial effects of the present invention are as follows: the constant current driving system provided by the present invention is used to drive a laser, and the system comprises a terminal and a constant current driving circuit electrically connected to each other: the constant current driving circuit comprises an MCU circuit, a first operational amplifier, a second operational amplifier, a third operational amplifier, a precision amplifier and a DC-DC power supply circuit; wherein the terminal is connected to the input end of the MCU circuit; the output end of the MCU circuit is connected to the positive input end of the first operational amplifier; the output end of the first operational amplifier is connected to the inverting input end of the second operational amplifier; the output end of the second operational amplifier is connected to the inverting input end of the third operational amplifier; the output end of the second operational amplifier is also connected to the precision amplifier; the output end of the third operational amplifier is connected to the DC-DC power supply circuit; one end of the laser is connected to the precision amplifier, and the other end of the laser is connected to the DC-DC power supply circuit; wherein the terminal is used to obtain external input laser data to be matched, and perform model comparison based on the laser data to be matched and the pre-stored model data to obtain a comparison result, and generate a control instruction based on the comparison result; the laser data is: power, voltage and current of the laser; the MCU circuit is used to perform constant current driving after receiving the control instruction. The present application proposes a constant current driving system, which includes: a terminal and an MCU circuit. The terminal receives external input laser data to be matched, performs a model comparison on the laser data and the model data stored in the terminal, obtains a comparison result, generates a corresponding control instruction based on the comparison result, and the terminal sends the control instruction to the MCU circuit. The MCU circuit performs a constant current driving operation based on the control instruction, thereby solving the problem of low adaptability of the constant current driving system to lasers of different models. The MCU controls the DAC output, and the driving circuit drives the DC-DC power supply circuit. Since the DC-DC power supply circuit adopts hardware closed-loop control, the stability and accuracy of the constant current are guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments 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 work.

[0018] Figure 1 A structural diagram of an embodiment of a constant current drive system provided by the present invention; Figure 2 A constant current drive system diagram provided by the present invention; Figure 3 A circuit diagram of an MCU (Micro Controller Unit) of an embodiment of a constant current drive system provided by the present invention; Figure 4 A precision amplifier circuit diagram of an embodiment of the constant current drive system provided by the present invention. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0020] In the description of the embodiments of the present application, unless otherwise specified, “plurality” means two or more than two.

[0021] The terms "including" and "having" and any variations thereof in the embodiments of the present invention are intended to cover non-exclusive inclusions. For example, a process, method, apparatus, product or equipment comprising a series of steps or modules is not necessarily limited to those steps or modules clearly listed, but may include other steps or modules not clearly listed or inherent to these processes, methods, products or equipment.

[0022] The naming or numbering of the steps in the embodiments of the present invention does not mean that the steps in the method flow must be executed in the time / logical sequence indicated by the naming or numbering. The execution order of the named or numbered process steps can be changed according to the technical purpose to be achieved, as long as the same or similar technical effects can be achieved.

[0023] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0024] The present invention provides a constant current driving system, which is described below respectively.

[0025] Figure 1 A system structure diagram of an embodiment of the constant current drive system provided by the present invention and Figure 2 The constant current drive system diagram provided by the present invention includes: The system includes terminals and a constant current drive circuit electrically connected to each other; The constant current driving circuit includes an MCU circuit 102, a first operational amplifier 103, a second operational amplifier 104, a third operational amplifier 105, a precision amplifier 106 and a DC-DC (direct current input and direct current output) power supply circuit 107; The terminal 101 is connected to the MCU circuit 102; The output terminal of the MCU circuit 102 is connected to the positive input terminal of the first operational amplifier 103; An output terminal of the first operational amplifier 103 is connected to an inverting input terminal of the second operational amplifier 104; The output terminal of the second operational amplifier 104 is connected to the inverting input terminal of the third operational amplifier 105; The output terminal of the second operational amplifier 104 is also connected to the precision amplifier 106; The output terminal of the third operational amplifier 105 is connected to the DC-DC power supply circuit 107; One end of the laser 108 is connected to the precision amplifier 106, and the other end of the laser 108 is connected to the DC-DC power supply circuit 107; The terminal 101 is used to obtain external input laser data to be matched, and perform model comparison based on the laser data to be matched and the pre-stored model data to obtain a comparison result, and generate a control instruction based on the comparison result; the laser data is: power, voltage and current of the laser; The MCU circuit 102 is used to perform constant current driving after receiving the control instruction.

[0026] It can be understood that the constant current drive system is mainly composed of: a host computer (terminal 101), an MCU controller, a digital-to-analog / analog-to-digital converter built into the single-chip microcomputer, a drive circuit, a constant current circuit and a laser.

[0027] The present application proposes a constant current drive system, which includes: a terminal 101 and an MCU circuit 102. The terminal 101 receives external input laser data to be matched, compares the laser data with the laser data of various different models stored in the terminal, obtains the comparison result, generates the corresponding control instruction based on the comparison result, and the terminal sends the control instruction to the MCU circuit 102. The MCU circuit 102 performs constant current drive operation based on the control instruction. The host computer communicates with the MCU controller in real time and is responsible for the control operation of the constant current data and the display of the constant current data. The MCU controller communicates with the host computer in real time to realize the signal acquisition and control operation of the digital-to-analog / analog-to-digital converter. After the host computer sets the parameters, it communicates with the MCU controller. The MCU controls the output of the DAC (digital-to-analog converter), and the drive circuit drives the constant current circuit. Since the constant current circuit adopts hardware closed-loop control, the stability and accuracy of the constant current are guaranteed. It can be further understood that in Figure 2 In the embodiment, a MOS (Metal Oxide Semiconductor Field Effect Transistor), a high-precision amplifier 106, a first operational amplifier 103, a second operational amplifier 104, a third operational amplifier 105, a laser and a sampling resistor are used, and a dual power supply of ±3.3V is adopted for power supply.

[0028] The precision amplifier 106, the sampling resistor and the MOS tube constitute a constant current circuit.

[0029] The seventh resistor, the third operational amplifier 105 and the capacitor constitute a comparator integration circuit; the first operational amplifier 103 constitutes a follower circuit.

[0030] The positive input voltage of the third operational amplifier 105 and the seventh resistor form a virtual ground, and the voltage is approximately 0. The reverse input terminal of the third operational amplifier 105 must also be adjusted to 0 due to the virtual short voltage, and the gate voltage of the constant current MOS tube is controlled together with the negative input voltage of the third operational amplifier 105 (compared with the integral output), thereby controlling the conduction degree of the MOS tube, thereby controlling the drain current and the laser current to achieve the constant current purpose.

[0031] Since the voltage across the fifth resistor is approximately 0, when the DAC chip outputs the set voltage LD_SET, the inverse proportional circuit formed by the fifth resistor will output a reverse voltage -LD_SET, setting the voltage amplification factor of the precision amplifier 106 to 1. Compared with the traditional sampling resistor single-ended voltage sampling, the precision amplifier 106 has ultra-high input impedance, extremely good CMRR (Common Mode Rejection Ratio, common mode rejection ratio), low input offset, and low output impedance, which improves the sampling speed and reduces noise.

[0032] The first operational amplifier 103 and the second operational amplifier 104 both use virtual grounding for input, and all operational amplifiers use low offset voltage, low noise, low input bias current, rail-to-rail I / O, e-trim™ precision operational amplifiers to further reduce loop noise.

[0033] In some embodiments of the present invention, the terminal 101 is connected to the MCU circuit 102, including: The terminal 101 is connected to the MCU circuit 102 via a SPI (Serial Peripheral interface).

[0034] It can be understood that the host computer communicates with the MCU controller in real time and is responsible for the control operation and display of the constant current data. The MCU controller communicates with the host computer in real time to realize the signal acquisition and control operation of the digital-to-analog / analog-to-digital converter.

[0035] In some embodiments of the present invention, the circuit further includes: a first resistor; the output terminal of the first operational amplifier 103 is connected to the inverting input terminal of the second operational amplifier 104 through the first resistor.

[0036] It can be understood that the output terminal of the first operational amplifier 103 is connected to the inverting input terminal of the second operational amplifier 104 via a first resistor.

[0037] In some embodiments of the present invention, the circuit further includes: a second resistor; one end of the second resistor is connected to the positive input end of the second operational amplifier 104, and the other end of the second resistor is grounded.

[0038] It can be understood that one end of the second resistor is connected to the positive input end of the second operational amplifier 104, and the other end of the second resistor is grounded.

[0039] In some embodiments of the present invention, the circuit further includes: a third resistor; one end of the third resistor is connected to the inverting input end of the second operational amplifier 104 , and the other end of the third resistor is connected to the output end of the second operational amplifier 104 .

[0040] It can be understood that one end of the third resistor is connected to the inverting input end of the second operational amplifier 104 , and the other end of the third resistor is connected to the output end of the second operational amplifier 104 .

[0041] In some embodiments of the present invention, the circuit further includes: a fourth resistor, a fifth resistor and a sixth resistor; The fourth resistor, the fifth resistor and the sixth resistor intersect at one point; One end of the fourth resistor is connected to the output end of the second operational amplifier 104; One end of the fifth resistor is grounded; One end of the sixth resistor is connected to the precision amplifier 106 .

[0042] It can be understood that the fourth resistor, the fifth resistor and the sixth resistor intersect at one point; One end of the fourth resistor is connected to the output end of the second operational amplifier 104; One end of the fifth resistor is grounded; One end of the sixth resistor is connected to the precision amplifier 106 .

[0043] In some embodiments of the present invention, the circuit further includes: a sampling resistor; the sampling resistor is connected in parallel with the precision amplifier 106 .

[0044] It can be understood that the sampling resistor is connected in parallel with the precision amplifier 106 .

[0045] In some embodiments of the present invention, the circuit further comprises: a capacitor; One end of the capacitor intersects with the inverting input terminal of the third operational amplifier 105, the fourth resistor, the fifth resistor and the sixth resistor at a point; The other end of the capacitor is connected to the output end of the third operational amplifier 105 .

[0046] It can be understood that one end of the capacitor intersects with the inverting input terminal of the third operational amplifier 105, the fourth resistor, the fifth resistor, and the sixth resistor at one point; The other end of the capacitor is connected to the output end of the third operational amplifier 105 .

[0047] In some embodiments of the present invention, the circuit further includes: a seventh resistor; one end of the seventh resistor is grounded, and the other end of the seventh resistor is connected to the positive input terminal of the third operational amplifier 105 .

[0048] It can be understood that one end of the seventh resistor is grounded, and the other end of the seventh resistor is connected to the positive input end of the third operational amplifier 105 .

[0049] In some embodiments of the present invention, the circuit further includes: an eighth resistor and a MOS tube; One end of the eighth resistor is connected to the output end of the third operational amplifier 105, and the other end of the eighth resistor is connected to the MOS tube; The other end of the MOS tube is connected to the laser 108 , and the third end of the MOS tube is also connected to the precision amplifier 106 .

[0050] The laser is connected to the output end of the DC-DC power supply circuit 107 .

[0051] It is understandable that the laser current setting improves the current accuracy, 16-bit DAC; low offset voltage, low noise, low input bias current, rail-to-rail I / O, e-trim™ precision operational amplifiers are used to reduce noise, and ultra-low noise LDO (linear regulator) is used to further reduce LD (semiconductor laser) power supply noise. The instrumentation amplifier is used as the sampling circuit to improve the common mode rejection ratio, and the high-precision low-temperature drift sampling resistor is used to improve the current stability and accuracy.

[0052] It should be noted that the main working principle of the laser is mainly based on the principles of stimulated radiation and optical resonance. In the laser, the pump source provides energy to excite the electrons of atoms or ions in the laser medium, making them in an excited state. When the excited atoms or ions transition to the ground state, a beam of light with the same frequency as the pump source and good coherence will be emitted, that is, the laser beam. Two high-reflectivity optical mirrors are installed in the optical resonant cavity, one of which is a semi-transparent mirror and the other is a full-reflection mirror. Through multiple reflections in the optical resonant cavity, the intensity of the laser is enhanced, and a laser output light path is formed to become a laser beam.

[0053] The role of the tuner in the laser is to adjust the wavelength and frequency of the laser to meet different application requirements. Common tuners include lattice tuners, mechanical tuners, electro-optical tuners, etc.

[0054] The output coupler outputs the laser beam from the inside of the laser to the outside. The choice of the output coupler will affect the output power and beam quality of the laser.

[0055] In short, the structure and working principle of the laser mainly rely on the principle of optical resonance and stimulated radiation. Through the combination of appropriate laser medium, optical resonator, pump source, tuner and output coupler, the output of different wavelengths, frequencies and powers can be achieved. Lasers are widely used in medicine, manufacturing, science and other fields.

[0056] The basic components of a laser include laser medium, excitation source, optical feedback element, output optical component, etc. These parts cooperate with each other and work together to achieve the generation and output of laser.

[0057] The basic components and functions of the laser are as follows: 1. Laser medium: Laser medium is the main part of the laser that generates laser light. It can convert energy into laser light. Gas, solid, liquid and even semiconductor materials are often used as laser media, and their physical properties and working conditions are also different.

[0058] 2. Excitation source: The excitation source is the part of the laser that generates energy. It can deliver a large amount of electrical energy, light energy or chemical energy to the laser medium, enabling it to generate laser light. Common excitation sources include laser diodes, gas discharges, chemical reactions, etc.

[0059] 3. Optical feedback element: Optical feedback element refers to various reflection, transmission and reflection-transmission structures, which can allow the laser beam to be transmitted along a certain optical path, and after strong focusing, finally gather the scattered light into a beam of strong light. It mainly includes optical geometric reflectors, optical resonant cavities, etc.

[0060] 4. Output optical components: Output optical components usually refer to the way the laser is emitted. The light beam is output by jumping mirrors or optical fiber transmission, so that the light beam can be output to the specified area as purely as possible optically. This part includes output optical fiber, output lens, etc.

[0061] The above four parts are combined together through specific optical design to form a stable and reliable laser. The optimization and coordination of these parts are the basis for the laser to generate coherent light radiation and obtain high-quality laser beam output.

[0062] There are many ways to classify lasers, which can be divided into several types such as solid, gas, liquid, semiconductor, dye and optical fiber: (1) Solid state lasers are generally small and strong, with high pulse radiation power and a wide range of applications. For example, Nd:YAG lasers. Nd (neodymium) is a rare earth element, and YAG stands for yttrium aluminum garnet, which has a crystal structure similar to ruby. There are also Tm:YAG, Ho:YAG, Ho:YAG, etc.

[0063] (2) Semiconductor lasers are small in size, light in weight, long in life, and simple in structure, making them particularly suitable for use in aircraft, warships, vehicles, and spacecraft. Semiconductor lasers can change the wavelength of lasers through external electric fields, magnetic fields, temperature, pressure, etc., and can directly convert electrical energy into laser energy, so they are developing rapidly.

[0064] (3) Gas laser is a laser that generates coherent light by releasing electric current through gas. It has good monochromaticity and coherence, and the laser wavelength can reach thousands of kinds, so it is widely used. Gas laser has simple structure, low cost and easy operation. It is widely used in industry, agriculture, medicine, precision measurement, holographic technology and other fields. Gas laser has many excitation modes such as electrical energy, thermal energy, chemical energy, light energy and nuclear energy.

[0065] (4) Dye lasers, which use liquid dyes as working materials, were introduced in 1966 and are widely used in various scientific research fields. Currently, about 500 dyes that can produce lasers have been discovered. These dyes can be dissolved in alcohol, benzene, acetone, water or other solutions. They can also be contained in organic plastics in solid form, or sublimate into vapor and appear in gaseous form. Therefore, dye lasers are also called "liquid lasers". The outstanding feature of dye lasers is that the wavelength can be continuously adjusted. There are many types of fuel lasers, which are low in price and high in efficiency. The output power is comparable to that of gas and solid lasers. They are used in spectroscopy, photochemistry, medicine and agriculture.

[0066] (5) Chemical Laser: Some chemical reactions produce enough high-energy atoms to release large amounts of energy that can be used to produce laser effects. This is mainly used in weapons. For example, hydrogen fluoride lasers can provide continuous output power in the megawatt range.

[0067] (6) Free electron laser: This type of laser is more suitable for producing high-power radiation than other types. Its working mechanism is unique. It obtains tens of millions of volts of high-energy adjusted electron beam from the accelerator, and forms energy levels of different energy states through a periodic magnetic field, generating stimulated radiation.

[0068] (7) Excimer laser (actually also a type of gas laser) is a type of ultraviolet gas laser. The laser light emitted by the molecules formed by the mixed gas of an excited inert gas and another gas (inert gas or halogen) when it transitions to its ground state is called an excimer laser. Excimer laser is a low-energy laser with no thermal effect. It is a pulsed laser with strong directionality, high wavelength purity and high output power. The photon energy wavelength range is 157-353 nanometers, and the pulse time is tens of nanoseconds. It is ultraviolet light. The most common wavelengths are 157 nm, 193 nm, 248 nm, 308 nm, and 351-353 nm.

[0069] (8) Fiber lasers use gain media (rare earth elements) in optical fibers to amplify optical signals. There are two types of fiber lasers: single-ended pumping and double-ended pumping. The latter can achieve higher output power. Coherent synthesis technology, which is still under development, can further expand the output power.

[0070] Figure 3 The MCU circuit 102 of one embodiment of the constant current drive system provided by the present invention and Figure 4 The circuit diagram of the precision amplifier 106 of one embodiment of the constant current drive system provided by the present invention includes: It can be understood that the single chip microcomputer selected in the present invention is STM32G474RET6 of STMicroelectronics, and the DAC uses ADI's 16-bit device AD5664RBRMZ-5REEL7. The DAC chip AD5664RBRMZ-5REEL7 is controlled by SPI communication to output a 0-4.096V voltage with a resolution of 4.096 / 2^16, which is used to set the current of the constant current circuit, thereby improving the current accuracy.

[0071] The constant current drive system provided by the present invention comprises: a terminal 101, an MCU circuit 102, a first operational amplifier 103, a second operational amplifier 104, a third operational amplifier 105, a precision amplifier 106 and a DC-DC power supply circuit 107; the terminal 101 is connected to the MCU circuit 102; the output end of the MCU circuit 102 is connected to the positive input end of the first operational amplifier 103; the output end of the first operational amplifier 103 is connected to the inverting input end of the second operational amplifier 104; the output end of the second operational amplifier 104 is connected to the inverting input end of the third operational amplifier 105; the output end of the second operational amplifier 104 is also connected to the precision amplifier 106; the output end of the third operational amplifier 105 is connected to the DC-DC power supply circuit 107; the precision amplifier 106 is connected to the DC-DC power supply circuit 107. The present application communicates with the MCU after setting the corresponding matching parameters for the terminal 101, the MCU controls the DAC output, and the driving circuit drives the DC-DC power supply circuit. Since the DC-DC power supply circuit adopts hardware closed-loop control, the stability and accuracy of the constant current are guaranteed.

[0072] The above embodiments are only used to illustrate the design ideas and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The protection scope of the present invention is not limited to the above embodiments. Therefore, any equivalent changes or decorations made according to the principles and design ideas disclosed by the present invention are within the protection scope of the present invention.

Claims

1. A constant current drive system for driving a laser, characterized in that: The system comprises terminals and a constant current drive circuit electrically connected to each other: The constant current drive circuit includes an MCU circuit, a first operational amplifier, a second operational amplifier, a third operational amplifier, a precision amplifier and a DC-DC power supply circuit; Wherein, the terminal is connected to the input terminal of the MCU circuit; The output terminal of the MCU circuit is connected to the positive input terminal of the first operational amplifier; The output terminal of the first operational amplifier is connected to the inverting input terminal of the second operational amplifier; The output terminal of the second operational amplifier is connected to the inverting input terminal of the third operational amplifier; The output terminal of the second operational amplifier is also connected to the precision amplifier; The output terminal of the third operational amplifier is connected to the DC-DC power supply circuit; One end of the laser is connected to a precision amplifier, and the other end of the laser is connected to a DC-DC power supply circuit; The terminal is used to obtain external input laser data to be matched, and compare the model based on the laser data to be matched and the pre-stored model data to obtain a comparison result, and generate a control instruction based on the comparison result; the laser data is: power, voltage and current of the laser; The MCU circuit is used to perform constant current driving after receiving the control instruction.

2. The constant current drive system according to claim 1, characterized in that: The terminal is connected to the MCU circuit, including: The terminal is connected to the MCU circuit via SPI.

3. The constant current drive system according to claim 1, characterized in that: The circuit further includes: a first resistor; the output end of the first operational amplifier is connected to the inverting input end of the second operational amplifier through the first resistor.

4. The constant current drive system according to claim 3, characterized in that: The circuit also includes: a second resistor; one end of the second resistor is connected to the positive input end of the second operational amplifier, and the other end of the second resistor is grounded.

5. The constant current drive system according to claim 4, characterized in that: The circuit further includes: a third resistor; one end of the third resistor is connected to the inverting input end of the second operational amplifier, and the other end of the third resistor is connected to the output end of the second operational amplifier.

6. The constant current drive system according to claim 5, characterized in that: The circuit further includes: a fourth resistor, a fifth resistor and a sixth resistor; The fourth resistor, the fifth resistor and the sixth resistor intersect at one point; One end of the fourth resistor is connected to the output end of the second operational amplifier; One end of the fifth resistor is grounded; One end of the sixth resistor is connected to the precision amplifier.

7. The constant current drive system according to claim 6, characterized in that: The circuit also includes: a sampling resistor; the sampling resistor is connected in parallel with the precision amplifier.

8. The constant current drive system according to claim 7, characterized in that: The circuit further includes: a capacitor; One end of the capacitor intersects with the inverting input terminal of the third operational amplifier, the fourth resistor, the fifth resistor and the sixth resistor at a point; The other end of the capacitor is connected to the output end of the third operational amplifier.

9. The constant current driving system according to claim 8, characterized in that: The circuit further includes: a seventh resistor; one end of the seventh resistor is grounded, and the other end of the seventh resistor is connected to the positive input end of the third operational amplifier.

10. The constant current driving system according to claim 9, characterized in that: The circuit further includes: an eighth resistor and a MOS tube; One end of the eighth resistor is connected to the output end of the third operational amplifier, and the other end of the eighth resistor is connected to the MOS tube; The other end of the MOS tube is connected to the laser, and the third end of the MOS tube is also connected to the precision amplifier.

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