Driving circuit suitable for electromagnetic MEMS micro galvanometer

Abstract

A drive circuit suitable for an electromagnetic MEMS micro galvanometer belongs to the technical field of micro electro mechanical systems, uses a DAC pin of a master control single-chip microcomputer to output a voltage waveform, uses an operational amplifier to build the drive circuit, can more conveniently control the rotation angle of the micro galvanometer, uses a voltage follower to increase the drive capability, and improves the drive capability of a DAC output signal of the master control single-chip microcomputer. The differential amplifier is used for converting a positive half-cycle voltage signal output by the single-chip microcomputer into a positive and negative half-cycle signal, and positive and negative angle rotation of the micro galvanometer is achieved. A driver is designed according to the'virtual short 'principle of an operational amplifier, conversion from voltage to current is achieved, through the voltage follower, the differential amplifier and the driver, the operational amplifier is fully used for building a driving circuit, the circuit structure is simple, additional noise and errors caused by a complex circuit are avoided, the control accuracy is improved, and meanwhile, the circuit structure is simple. The circuit is composed of common electronic elements, the control purpose is achieved, meanwhile, the production cost can be reduced, and the production process is simplified.

Description

Technical Field

[0001] The utility model belongs to the technical field of micro-electromechanical systems, and in particular relates to a driving circuit suitable for an electromagnetic MEMS micro-vibration mirror. Background Art

[0002] The driving method of electromagnetic MEMS micro-mirrors is mainly based on the principle of Lorentz force. In the magnetic field generated by the magnet, the current flowing in the coil surrounding the galvanometer generates a Lorentz force that causes the galvanometer to tilt based on Fleming's law. Specifically, dual-axis MEMS micromirrors are usually driven using two electrodes, each of which is embedded near the reflector of the micromirror. When a current passes through one pole, a magnetic field is generated at that location, which interacts with the charges around the reflector to generate a force that causes the reflector to rotate. At the same time, due to changes in the position and direction of the reflector, the position and direction of the reflected light will also change.

[0003] In addition, the driving circuit of the electromagnetic MEMS micro-vibration mirror usually uses feedback control to achieve precise position and direction adjustment. According to the position and direction of the reflected light detected by the sensor, the circuit can automatically adjust the magnitude and direction of the current to achieve precise control. This closed-loop feedback control method can provide very precise adjustment and stability.

[0004] This driving method enables the electromagnetic MEMS micro-vibration mirror to have dual-axis functions, which is lower in cost than the current galvanometer, and has a lower driving voltage and is easier to use. In addition, its mirror diameter is usually only a few millimeters, and it has the advantages of light weight, small size, easy mass production, and low production cost. It has outstanding performance in optical, mechanical properties and power consumption. Therefore, electromagnetic MEMS micro-vibration mirrors have been widely used in barcode scanning, high-definition projection, laser confocal microscopy systems and other fields.

[0005] In general, the driving method of electromagnetic MEMS micro-mirror is both scientific and practical, and can achieve precise control of laser beams, providing efficient and reliable solutions for various application scenarios. Although the electromagnetic MEMS micro-mirror driving circuit has many advantages, such as precise control, small size, and light weight, it also has some disadvantages:

[0006] Drive complexity: To achieve precise control, the drive circuit usually needs to adopt complex feedback control mechanisms. This increases the complexity of the circuit design and may introduce additional noise and errors.

[0007] Manufacturing cost: Although electromagnetic MEMS micro-vibration mirrors are low-cost when produced in large quantities, their drive circuits may require the use of high-quality electronic components and complex production processes, which may increase the overall manufacturing cost. Utility Model Content

[0008] The purpose of the utility model is to solve the problems in the prior art and provide a driving circuit suitable for an electromagnetic MEMS micro-vibration mirror to solve the technical problem that the prior art cannot solve the driving complexity.

[0009] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0010] A driving circuit suitable for an electromagnetic MEMS micro-vibration mirror comprises a voltage follower, wherein the input end of the voltage follower is connected to a DAC pin of a main control microcontroller, the output end of the voltage follower is connected to a differential amplifier, and the output end of the differential amplifier is connected to a driver.

[0011] Preferably, the output end of the voltage follower is connected to the inverting end of the differential amplifier.

[0012] Preferably, the voltage follower includes a first operational amplifier and a second operational amplifier, the non-inverting input terminal of the first operational amplifier is connected to the DAC pin of the main control microcontroller, and the inverting input terminal is connected to the output terminal and then connected to the non-inverting input terminal of the second operational amplifier, the inverting input terminal of the second operational amplifier is connected to two branches, one branch is grounded through a resistor R52, and the other branch and the output terminal are both connected to a jumper JP19, and the differential amplifier is connected to the second operational amplifier through the jumper JP19.

[0013] Preferably, the resistor R52 is 220Ω.

[0014] Preferably, the first operational amplifier and the second operational amplifier are both dual operational amplifiers.

[0015] Preferably, the driver includes a third operational amplifier, whose in-phase input terminal is connected to the output terminal of the differential amplifier, and the inverting input terminal of the third operational amplifier includes two branches, one branch is grounded after passing through a resistor R51, and the other branch is connected to the output terminal of the third operational amplifier via a jumper JP18.

[0016] Preferably, the third operational amplifier is a high-performance low-noise dual operational amplifier.

[0017] Preferably, the resistor R51 is 110Ω.

[0018] Compared with the prior art, the utility model has the following beneficial effects:

[0019] The present application discloses a driving circuit suitable for an electromagnetic MEMS micro-vibration mirror. In order to more conveniently control the rotation angle of the micro-vibration mirror, the DAC pin of the main control microcontroller is used to output a voltage waveform, and an operational amplifier is used to build a driving circuit. In order to improve the driving ability of the DAC output signal of the main control microcontroller, a voltage follower is used to increase the driving ability. In order to realize the positive and negative angle rotation of the micro-vibration mirror, a differential amplifier is used to convert the positive half-cycle voltage signal output by the microcontroller into a positive and negative half-cycle signal. The driver is designed according to the "virtual short" principle of the operational amplifier to realize the conversion from voltage to current. The present application uses a voltage follower, a differential amplifier and a driver to fully utilize the operational amplifier to build a driving circuit, so that the circuit structure is simple, and the complex circuit is avoided. The introduction of additional noise and errors, thereby improving the accuracy of the control, and the circuit is composed of common electronic components, which can reduce production costs and simplify production processes while achieving the control purpose. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 A driving circuit diagram suitable for an electromagnetic MEMS micro-vibration mirror according to an embodiment of the utility model;

[0022] Figure 2 This is a simulation waveform diagram of an embodiment of the utility model.

[0023] Among them, 1-first channel; 2-second channel. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Generally, the components of the embodiment of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0025] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0027] In the description of the embodiments of the present utility model, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the utility model product is usually placed when in use, it is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0028] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0029] In the description of the embodiments of the present utility model, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0030] The utility model is further described in detail below with reference to the accompanying drawings:

[0031] See also Figure 1 The present application discloses a driving circuit suitable for an electromagnetic MEMS micro-vibration mirror, including a voltage follower, wherein the input end of the voltage follower is connected to the DAC pin of a main control microcontroller, the output end of the voltage follower is connected to a differential amplifier, and the output end of the differential amplifier is connected to a driver.

[0032] In order to more conveniently control the rotation angle of the micro-vibration mirror, the DAC pin of the main control microcontroller is used to output the voltage waveform, and an op amp is used to build a driving circuit. In order to improve the driving ability of the DAC output signal of the main control microcontroller, a voltage follower is used to increase the driving ability. In order to realize the positive and negative angle rotation of the micro-vibration mirror, a differential amplifier is used to convert the positive half-cycle voltage signal output by the microcontroller into a positive and negative half-cycle signal. The driver is designed according to the "virtual short" principle of the op amp to realize the conversion from voltage to current. This application uses a voltage follower, a differential amplifier and a driver to fully utilize the op amp to build a driving circuit, so that the circuit structure is simple, and the complex circuit introduces additional noise and errors, thereby improving the accuracy of the control. In addition, the circuit is composed of common electronic components, which can reduce production costs and simplify production processes while achieving the control purpose.

[0033] In some embodiments, the output terminal of the voltage follower is connected to the inverting terminal of the differential amplifier.

[0034] In some embodiments, the voltage follower includes a first operational amplifier and a second operational amplifier, the non-inverting input terminal of the first operational amplifier is connected to the DAC pin of the main control microcontroller, and the inverting input terminal is connected to the output terminal and then connected to the non-inverting input terminal of the second operational amplifier. The inverting input terminal of the second operational amplifier is connected to two branches, one branch is grounded through a resistor R52, and the other branch and the output terminal are both connected to a jumper JP19, and the differential amplifier is connected to the second operational amplifier through the jumper JP19.

[0035] In some embodiments, the resistor R52 is 220Ω.

[0036] In some embodiments, the first operational amplifier and the second operational amplifier are both dual operational amplifiers.

[0037] Further optimized, the first operational amplifier and the second operational amplifier are both LMV358B-VR dual operational amplifiers.

[0038] In some embodiments, the driver includes a third operational amplifier, whose in-phase input terminal is connected to the output terminal of the differential amplifier, and the inverting input terminal of the third operational amplifier includes two branches, one branch is grounded after passing through a resistor R51, and the other branch is connected to the output terminal of the third operational amplifier through a jumper JP18. In order to achieve voltage-to-current conversion, the driver is designed according to the "virtual short" principle of the operational amplifier.

[0039] In some embodiments, the third operational amplifier is a high performance low noise dual operational amplifier.

[0040] Further optimized, the third operational amplifier is a NE5532DR high performance low noise dual operational amplifier.

[0041] In some embodiments, the resistor R51 is 110Ω.

[0042] In order to more conveniently control the rotation angle of the micro-vibration mirror, the present application uses the DAC pin of the main control microcontroller to output the voltage waveform, and uses an op amp to build a drive circuit. In order to improve the driving capability of the DAC output signal of the main control microcontroller, a voltage follower is used to increase the driving capability. In order to realize the positive and negative angle rotation of the micro-vibration mirror, a differential amplifier is used to convert the positive half-cycle voltage signal output by the microcontroller into a positive and negative half-cycle signal.

[0043] [Example 1]

[0044] like Figure 1 The figure shows a driving circuit diagram for an electromagnetic MEMS micro-vibration mirror proposed by the utility model. Since the voltage driving capability of the output of the DAC pin of the single-chip microcomputer is weak, it is necessary to connect the output pin SINOUT of the single-chip microcomputer to the voltage follower U7A to increase the driving capability. The voltage signal MEMSOUT output by U7B is connected to the inverting end of the differential amplifier U5A. In order to realize the positive and negative angle rotation of the micro-vibration mirror, the driving voltage also needs to have positive and negative half cycles. The positive half-cycle voltage signal output by the single-chip microcomputer is converted into a positive and negative half-cycle signal through the differential amplifier U5A. U5B is the most important VI driver. When the micro-vibration mirror is connected in series to JP18, there is only one path in the U5B circuit. According to the principle of "virtual short" of the ideal operational amplifier, the voltage at the in-phase terminal of U5B is equal to the voltage at the inverting terminal. Therefore, the path current formed by JP18 and R51 is determined by the resistance value of the resistor R51 and the positive input voltage.

[0045] [Example 2] Using the driving circuit to drive the MEMS micro-vibration mirror in the laser radar

[0046] Hamamatsu S12237-03P, the micro-vibration mirror is a single-axis electromagnetic micro-vibration mirror. The rotation angle of the Hamamatsu micro-vibration mirror is between -15° and +15°. When working in linear mode, the driving current frequency is 1Hz to 100Hz.

[0047] The driving circuit was built through simulation software, and the power supply was used to simulate the microcontroller to output an analog signal, which was a sine wave signal with a frequency of 50Hz and a peak voltage of 1.65V. Observe the simulation waveform, the first channel 1 is the input sine signal, and the second channel 2 is the output current signal, such as Figure 2 As shown, the display ratio is 1mA / 1V. The circuit successfully converts the input voltage signal into a sinusoidal current signal with a peak value of 15mA, which meets the driving current requirement of the micro-vibration mirror. The reliability of the driving circuit proposed by the utility model has been verified through simulation.

[0048] The driving circuit proposed in the utility model is applied to the laser radar, and the DAC pin of the single-chip microcomputer is used to output a triangle wave with a peak-to-peak value of 3.3V, which reaches the pin interface of the MEMS micro-vibration mirror through the driving circuit. By observing the oscilloscope, it can be seen that the output waveform of the MEMS driving circuit is a triangle wave with positive and negative half cycles. Due to the scanning angle requirements of the laser radar, the scanning angle of the MEMS micro-vibration mirror is -5°~+5°, which realizes the driving requirements of the MEMS micro-vibration mirror.

[0049] Through simulation and the process of building the actual lidar circuit, the driving circuit proposed in the utility model can be well applied to driving the electromagnetic MEMS micro-vibration mirror. By designing a simple operational amplifier control mechanism, not only the complexity of the circuit design is significantly reduced, but also the signal path is simplified, making the entire circuit more stable and reliable, effectively reducing the possible noise and errors, thereby improving the performance of the circuit.

[0050] In addition, the driver circuit also takes the cost factor into full consideration in the selection of components. It uses widely used electronic components on the market, which are low-priced, stable in performance, and easy to purchase and replace. Such a design not only ensures the reliability and durability of the circuit, but also significantly reduces the overall manufacturing cost.

[0051] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may be subject to various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A driving circuit suitable for an electromagnetic MEMS micro-vibration mirror, characterized in that: It comprises a voltage follower, the input end of the voltage follower is connected to the DAC pin of the main control microcontroller, the output end of the voltage follower is connected to the differential amplifier, and the output end of the differential amplifier is connected to the driver.

2. A driving circuit suitable for an electromagnetic MEMS micro-vibration mirror according to claim 1, characterized in that: The output end of the voltage follower is connected to the inverting end of the differential amplifier.

3. The driving circuit suitable for an electromagnetic MEMS micro-vibration mirror according to claim 1, characterized in that: The voltage follower includes a first operational amplifier and a second operational amplifier. The in-phase input terminal of the first operational amplifier is connected to the DAC pin of the main control microcontroller, and the inverting input terminal is connected to the output terminal and then to the in-phase input terminal of the second operational amplifier. The inverting input terminal of the second operational amplifier is connected to two branches, one branch is grounded through a resistor R52, and the other branch and the output terminal are both connected to a jumper JP19. The differential amplifier is connected to the second operational amplifier through the jumper JP19.

4. The driving circuit suitable for an electromagnetic MEMS micro-vibration mirror according to claim 3, characterized in that: The resistor R52 is 220Ω.

5. The driving circuit suitable for an electromagnetic MEMS micro-vibration mirror according to claim 3, characterized in that: The first operational amplifier and the second operational amplifier are both dual operational amplifiers.

6. The driving circuit suitable for an electromagnetic MEMS micro-vibration mirror according to claim 1, characterized in that: The driver includes a third operational amplifier, whose in-phase input terminal is connected to the output terminal of the differential amplifier. The inverting input terminal of the third operational amplifier includes two branches, one branch is grounded after passing through a resistor R51, and the other branch is connected to the output terminal of the third operational amplifier by a jumper JP18.

7. A driving circuit suitable for an electromagnetic MEMS micro-vibration mirror according to claim 6, characterized in that: The third operational amplifier is a high-performance low-noise dual operational amplifier.

8. The driving circuit suitable for an electromagnetic MEMS micro-vibration mirror according to claim 6, characterized in that: The resistor R51 is 110Ω.

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