Scanner driving circuit, scanner device and laser radar

Abstract

The present disclosure provides a scanner driving circuit, a scanner device and a laser radar. The scanner driving circuit comprises: a first operational amplifier, an input end of the first operational amplifier being configured to receive a first input signal; a first power amplifier circuit, a first end of the first power amplifier circuit being configured to be coupled with an output end of the first operational amplifier, and a second end of the first power amplifier circuit being configured to be coupled with a first end of the scanner; a second operational amplifier, an input end of the second operational amplifier being configured to receive a second input signal; and a second power amplifier circuit, a first end of the second power amplifier circuit being configured to be coupled with an output end of the second operational amplifier, and a second end of the second power amplifier circuit being configured to be coupled with a second end of the scanner, wherein the first operational amplifier and the second operational amplifier comprise a feedback circuit configured to make a direct current voltage across the scanner a predetermined value based on the corresponding first input signal or the second input signal.

Description

Technical Field

[0001] This disclosure relates to the field of circuit technology, and more specifically, to a scanner driving circuit, a scanner device including the scanner driving circuit, and a lidar including the scanner device. Background Technology

[0002] The scanner is a crucial component of LiDAR (LiDAR system). It alters the laser beam's emission direction, enabling coverage of the LiDAR's field of view (FOV). Accurate control of the scanner's rotation angle is essential for obtaining accurate LiDAR detection data. Existing scanner drive circuits suffer from inaccurate control, particularly for reciprocating oscillating scanners, where jamming or inaccurate control frequently occurs at the reversal points, impacting LiDAR detection accuracy. Therefore, accurately driving the scanner's movement is a problem that needs to be solved in the LiDAR field. Summary of the Invention

[0003] This disclosure provides a scanner driver circuit, comprising: a first operational amplifier, the input terminal of which is configured to receive a first input signal; a first power amplifier circuit, a first terminal of which is configured to be coupled to the output terminal of the first operational amplifier, and a second terminal of which is configured to be coupled to a first terminal of a scanner; a second operational amplifier, the input terminal of which is configured to receive a second input signal; and a second power amplifier circuit, a first terminal of which is configured to be coupled to the output terminal of the second operational amplifier, and a second terminal of which is configured to be coupled to a second terminal of the scanner, wherein the first operational amplifier and the second operational amplifier include a feedback circuit, the feedback circuit being configured to cause the DC voltage division across the scanner to be a predetermined value based on the corresponding first input signal or the second input signal.

[0004] Optionally, the first operational amplifier includes a first feedback circuit, the first feedback circuit including: a first resistor, a first end of the first resistor being coupled to the inverting input terminal of the first operational amplifier, and a second end of the first resistor being grounded; and a second resistor, a first end of the second resistor being coupled to the inverting input terminal of the first operational amplifier, and a second end of the second resistor being coupled to the first terminal of the scanner.

[0005] Optionally, the second operational amplifier includes a second feedback circuit, which includes: a third resistor, the first end of which is coupled to the inverting input terminal of the second operational amplifier, and the second end of which is grounded; and a fourth resistor, the first end of which is coupled to the inverting input terminal of the second operational amplifier, and the second end of which is coupled to the second terminal of the scanner.

[0006] Optionally, the resistance values ​​of the first resistor, the second resistor, the third resistor, and the fourth resistor meet at least one of the following conditions: the ratio of the resistance value of the second resistor to the resistance value of the first resistor is equal to the ratio of the difference between the predetermined value and the DC voltage divider of the first input signal to the DC voltage divider of the first input signal; or, the ratio of the resistance values ​​of the fourth resistor to the resistance value of the third resistor is equal to the ratio of the difference between the predetermined value and the DC voltage divider of the second input signal to the DC voltage divider of the second input signal.

[0007] Optionally, the scanner driver circuit further includes at least one of the following: a fifth resistor disposed between the output terminal of the first operational amplifier and the first terminal of the scanner; or a sixth resistor disposed between the output terminal of the second operational amplifier and the second terminal of the scanner.

[0008] Optionally, the first power amplifier circuit and the second power amplifier circuit include Class B power amplifier circuits, wherein the Class B power amplifier circuits include PMOS and NMOS, and the PMOS and NMOS are configured to operate in the linear region.

[0009] Optionally, the predetermined value of the DC voltage divider of the scanner is set to the intermediate value between the first voltage of the PMOS connection and the second voltage of the NMOS connection.

[0010] Optionally, the first threshold voltage at which the NMOS begins to conduct is configured to be less than or equal to the second threshold voltage at which the PMOS begins to conduct.

[0011] Optionally, the scanner driver circuit further includes at least one of the following: a first capacitor disposed between the inverting input terminal of the first operational amplifier and the output terminal of the first operational amplifier; or, a second capacitor disposed between the inverting input terminal of the second operational amplifier and the output terminal of the second operational amplifier.

[0012] Optionally, the scanner driver circuit further includes at least one of the following: a seventh resistor disposed between the output terminal of the first operational amplifier and the control terminal of the first power amplifier circuit; or, an eighth resistor disposed between the output terminal of the second operational amplifier and the control terminal of the second power amplifier circuit.

[0013] Optionally, the scanner drive circuit further includes a third capacitor, which is configured to be connected in parallel with the scanner.

[0014] Optionally, the carrier phases of the first input signal and the second input signal are opposite.

[0015] This disclosure also provides a scanner device, including: a scanner, and a scanner driving circuit consistent with any embodiment of this disclosure, the scanner driving circuit being connected to the scanner and configured to drive the scanner to oscillate.

[0016] This disclosure also provides a lidar, including: a laser configured to emit a laser beam; and a scanner device consistent with any embodiment of this disclosure, the scanner device being configured to change the emission direction of the laser beam. Attached Figure Description

[0017] To further illustrate the various embodiments of this disclosure, reference will be made to the accompanying drawings. It should be understood that these drawings may depict only some embodiments of this disclosure and are therefore not intended to limit the scope of protection claimed by this disclosure.

[0018] Figure 1 An exemplary structural block diagram of a lidar consistent with some embodiments of this disclosure is shown.

[0019] Figure 2 A first embodiment of a scanner driver circuit consistent with some embodiments of this disclosure is shown.

[0020] Figure 3 A second embodiment of a scanner driver circuit consistent with some embodiments of this disclosure is shown. Detailed Implementation

[0021] The following description is made with reference to the accompanying drawings. The drawings illustrate, by way of example, some embodiments in which the claimed subject matter can be practiced. It should be understood that the following embodiments are intended to describe some examples for illustrative purposes and should not be construed as limiting the present disclosure; those skilled in the art can make appropriate modifications and adjustments to the disclosed embodiments without departing from the scope of the subject matter claimed herein, provided they fully understand the spirit of the present disclosure.

[0022] Unless otherwise defined, the terms used herein shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0023] The terms “first,” “second,” etc., used in the specification and claims of this application do not imply any order, quantity, or importance, but are merely used to distinguish different components or features.

[0024] The embodiments of this application are exemplary implementations or examples. References to "embodiment," "one embodiment," "some embodiments," "alternative embodiments," or "other embodiments" in the specification mean that a specific feature or construction described in connection with the embodiment is included in at least some, but not necessarily all, embodiments of the present technology. Various appearances of "embodiment," "one embodiment," or "some embodiments" do not necessarily refer to the same embodiment. Elements or aspects from one embodiment may be combined with elements or aspects from another embodiment.

[0025] In the description of this disclosure, the terms "upper," "lower," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are used only for the convenience of describing this disclosure, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure. In other embodiments where the placement orientation of the device or component is opposite or different from the orientation shown in the drawings, these positional descriptions may vary accordingly.

[0026] In the description of this disclosure, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0027] In the description of this disclosure, the terms "coupling" and "connection" can include direct or indirect coupling or connection.

[0028] LiDAR (Light Detection and Ranging) is a remote sensing technology. LiDAR uses lasers to measure distances and create detailed three-dimensional (3D) images of objects and landscapes. During object detection, the LiDAR emits a laser beam; upon encountering an object, the laser is reflected from the object's surface; the reflected light (also called the echo) is received by the LiDAR and converted into an electrical signal. The LiDAR processes this electrical signal to determine information about the object, such as its distance, position, or velocity. LiDAR systems can also be configured to create real-time 3D models of the environment, which can be represented as point clouds. A point cloud is a collection of three-dimensional data points representing the surfaces of objects, structures, and environments within a specific area. Each data point in the point cloud can be defined by its X, Y, and Z coordinates in space, representing its position in three-dimensional space. Using point clouds, vehicles can accurately identify the location of objects such as cars, pedestrians, and / or cyclists.

[0029] LiDAR can generate high-quality point clouds, which simplifies and improves the processing efficiency of driver assistance algorithms. LiDAR provides intelligent vehicles (such as autonomous vehicles) with high-resolution 3D perception results, enhancing their perception capabilities to handle more complex road conditions (such as dark environments or unknown objects on highways). LiDAR can be widely used in passenger cars and commercial vehicles equipped with Advanced Driver Assistance Systems (ADAS) and / or autonomous driving (automated transportation). LiDAR can also be applied to any suitable end device, such as drones or robots.

[0030] LiDAR can be categorized into mechanical, semi-solid-state, and solid-state lidar based on its scanning method. In semi-solid-state lidar, the laser and detector are fixed relative to the lidar housing, and the laser emission direction is changed by a scanner to achieve FOV coverage. Scanner lag or inaccurate control will affect the accuracy of lidar detection; for example, scanner lag will cause jitter in adjacent frames of point cloud data. Therefore, accurately driving the scanner movement is a problem that needs to be solved in the lidar field.

[0031] Figure 1 An example structural block diagram of a lidar consistent with some embodiments of this disclosure is shown. For example... Figure 1 As shown, the lidar 100 includes a laser emitting system 110, a laser receiving system 120, and a control and processing system 130. Optionally, the lidar 100 also includes a scanning system 140. The scanning system 140 may include a rotating optical engine, a unidirectional rotating polygonal mirror, a reciprocating oscillating mirror or galvanometer (e.g., a MEMS mirror, a GALVO mirror, etc.), and other components that can change the orientation of the laser beam in the environment.

[0032] Laser emitting system 110 emits a laser. Upon encountering object 10, the laser beam is reflected from the surface of object 10, forming an echo that returns to lidar 100. Laser receiving system 120 receives the reflected echo and converts it into an electrical signal. This signal is pre-processed (e.g., filtered, amplified, or converted from analog to digital) and provided to control and processing system 130. Control and processing system 130 processes the echo data to determine information about object 10, such as its distance, position, or velocity. This process is repeated millions of times per second to create an accurate, real-time 3D environment map, such as a point cloud. Computers in terminal devices such as vehicles can use the point cloud for safe navigation.

[0033] The laser emitting system 110 includes an excitation source (such as a driving circuit), a laser, and an emitting optics. The laser emits laser light under the drive of the excitation source, and the laser light exits through the emitting optics. The laser can be a vertical-cavity surface-emitting laser (VCSEL), an edge-emitting laser (EEL), or any other laser capable of generating laser light. The wavelength of the emitted laser light can be any of 905 nm, 940 nm, or 1550 nm; the laser can also emit laser light of other wavelengths. The excitation source can include a driver integrated circuit, such as an analog chip or a digital-analog hybrid chip.

[0034] The laser receiving system 120 includes a receiving optics and a detector. The receiving optics collects the echo reflected from an object and focuses the echo onto the detector. The detector uses the photoelectric effect to convert the echo into an electrical signal. The detector may include a single-photon detector, such as a single-photon avalanche diode (SPAD), a silicon photomultiplier (SiPM), or an avalanche photodiode (APD). The lidar 100 may also include a preprocessing circuit. This preprocessing circuit may include digitization circuitry, such as an analog-to-digital converter (ADC), which converts analog signals into digital signals for use with the control and processing system 130. Alternatively, the preprocessing circuit may include a time-to-digital converter (TDC); the echo is converted into an electrical signal by the detector and provided to the TDC; based on the received electrical signal, the TDC can determine the time information (e.g., a timestamp) of the echo and convert the time information into a digital signal for use with the control and processing system 130. The preprocessing circuit may also include analog front-end circuitry for channel selection and analog signal amplification. In some embodiments, the preprocessing circuit may be implemented as a system-on-chip (SOC) or an application-specific integrated circuit (ASIC). The transmitting and receiving optics include, for example, one or more optical devices such as lenses or lens groups, mirrors, filters, beam splitters, apertures, and homogenizers. The transmitting and receiving optics may be independently configured or may be fully or partially multiplexed.

[0035] The control and processing system 130 may include an information processing circuit and a light source control circuit. The information processing circuit processes electrical signals to determine information about the object. For example, the information processing circuit may include: an Application-Specific Integrated Circuit (ASIC), or a circuit implemented with a Programmable Logic Device (PLD), such as a Field Programmable Gate Array (FPGA), or a Microcontroller Unit (MCU), or a Digital Signal Processor (DSP). Another example is a Central Processing Unit (CPU). The light source control circuit sends control signals to the excitation source to control the excitation source to drive the laser to emit light, achieving pulsed laser emission. For example, the light source control circuit can send timing signals to control the laser emission timing. Furthermore, the light source control circuit can add pulse coding functionality by controlling one or more of the pulse interval, pulse intensity, and pulse width, thereby enhancing the anti-interference capability of the lidar. The light source control circuit and the information processing circuit can be integrated together, for example, integrated into a main control chip, or they can each be independent or partially independent chips. When the lidar 100 includes a scanning system 140, the control and processing system 130 can also include a scanning control circuit for controlling the scanning system 140. The scanning control circuit can be integrated with one or all of the light source control circuit and the information processing circuit; for example, the scanning control circuit, the light source control circuit, and the information processing circuit can be integrated into a main control chip; or they can each be independent or partially independent chips. In some embodiments, the control and processing system 130 can be implemented as a system-on-a-chip (SOC) or an application-specific integrated circuit (ASIC).

[0036] In applications, lidar can be installed on terminal devices to transmit the detected sensing data. The terminal devices then use this data to perform one or more functions, such as analysis, decision-making, or control. Terminal devices include, for example, vehicles, ships, aircraft (e.g., flying vehicles or drones), and robots (e.g., industrial robots or home robots).

[0037] Figure 2 A first embodiment of a scanner driver circuit consistent with some embodiments of this disclosure is shown. Figure 2The image shows a scanner 201. In some embodiments, the scanner 201 may be a combination of the above. Figure 1 The described scanning system 140 includes any of the various scanner types. Scanner 201 can be used to change, for example, the emission direction of a laser. For example, scanner 201 may include a tilting mirror, a coil, and a permanent magnet, wherein the coil is disposed on the tilting mirror (e.g., on the back of the tilting mirror), the permanent magnet is fixedly connected to the scanner's mounting base and disposed opposite to the coil, and the coil and... Figure 2 The scanner drive circuit shown is connected. For example, scanner 201 may include a tilting mirror, a coil, and a permanent magnet, wherein the permanent magnet is disposed on the tilting mirror (e.g., on the back of the tilting mirror), the coil is fixedly connected to the scanner's mounting base and disposed opposite to the permanent magnet, and the coil and... Figure 2 The scanner driver circuit connection is shown in the figure.

[0038] Figure 2 Also shown is a drive circuit 200 (also referred to herein as scanner drive circuit 200) for driving scanner 201. Scanner drive circuit 200 may correspond to the above combination. Figure 1 The described scan control circuit drives and controls the movement of the scanner 201. For example... Figure 2 As shown, the scanner driver circuit 200 may include a first operational amplifier 202, a first power amplifier circuit 203, a second operational amplifier 204, and a second power amplifier circuit 205. In some embodiments, such as Figure 2 As shown, the first operational amplifier 202 and the second operational amplifier 204 can be arranged symmetrically with respect to the scanner 201. The first power amplifier circuit 203 and the second power amplifier circuit 205 can be arranged symmetrically with respect to the scanner 201.

[0039] The input terminal of the first operational amplifier 202 is configured to receive a first input signal. The output terminal of the first operational amplifier 202 is configured to connect to the first terminal of the first power amplifier circuit 203 (e.g., ...). Figure 2 The left end of the first power amplifier circuit 203 shown is coupled. The second end of the first power amplifier circuit 203 (for example, Figure 2 The right end of the first power amplifier circuit 203 shown is configured to connect with the first end of the scanner 201 (e.g., Figure 2 The left end of the scanner 201 shown is coupled.

[0040] The input terminal of the second operational amplifier 204 is configured to receive a second input signal. The output terminal of the second operational amplifier 204 is configured to connect with the first terminal of the second power amplifier circuit 205 (e.g., ...). Figure 2 The right end of the second power amplifier circuit 205 shown is coupled. The second end of the second power amplifier circuit 205 (for example, Figure 2The left end of the second power amplifier circuit 205 shown is configured to connect with the second end of the scanner 201 (e.g., Figure 2 The scanner 201 shown is coupled at the right end.

[0041] The first operational amplifier 202 may include a feedback circuit 206, and the second operational amplifier 202 may include a feedback circuit 207. The feedback circuit 206 or the feedback circuit 307 may be configured to cause the DC voltage across the scanner 201 to be a predetermined value based on the corresponding first or second input signal.

[0042] In some embodiments of this disclosure, an input control signal (e.g., the first input signal or the second input signal mentioned above) can be applied to drive the scanner 201 to move through the scanner drive circuit 200 mentioned above. This can accurately control the movement of the scanner, reduce scanner stuttering and other phenomena, and improve the accuracy of the lidar detection results.

[0043] The scanner 201 can be driven to oscillate in a desired manner by inputting different control signals. For example, in an example where the scanner 201 is applied to a lidar system, the oscillation pattern of the scanner 201 can be determined based on the scanning requirements of the lidar. As an example, in some embodiments, if a sinusoidal oscillation of the scanner 201 is desired, the input control signals (e.g., the first and second input signals described above) can be sinusoidal pulse width modulation (SPWM) signals. In other embodiments, if a uniform oscillation of the scanner 201 is desired, requiring a linearly changing current flowing through the scanner 201, the input control signals (e.g., the first and second input signals described above) can be ramp modulation signals. In some embodiments, the input control signals can be other types of pulse width modulation signals. In some embodiments, the control signals on both sides (e.g., the first and second input signals) can be a pair of input control signals with opposite carrier phases. For example, when a sinusoidal oscillation of the scanner 201 is desired, the first and second input signals can be a pair of SPWM signals with opposite carrier phases. For example, when it is desired that the scanner 201 swings at a constant speed, the first input signal and the second input signal can be a pair of ramp modulated signals with opposite carrier phases.

[0044] Figure 3 A second embodiment of the scanner driver circuit 300, consistent with some embodiments of this disclosure, is shown. It should be noted that, for clarity and simplicity of description, Figure 3 The diagram shows circuit diagrams including various embodiments of the present disclosure. However, it should not be considered as... Figure 3 The circuit structure described herein is to be understood as the only or necessary implementation of this disclosure. Various embodiments of this disclosure may include, for example... Figure 3One or more circuits or components in the structure shown, and not Figure 3 All circuits or components in the present disclosure. Furthermore, some embodiments of this disclosure may also include those not in... Figure 3 One or more circuits or elements shown in the diagram.

[0045] Figure 3 Including with Figure 2 One or more identical or corresponding components or circuits. For example, Figure 3 The scanner 301 in the middle corresponds to Figure 2 Scanner 201 in the middle, Figure 3 The first operational amplifier 302 and the second operational amplifier 304 in the middle can respectively correspond to Figure 2 The first operational amplifier 202 and the second operational amplifier 204 are described in conjunction with [the other two operational amplifiers]. For clarity, [the following is also mentioned]. Figure 3 The embodiments shown are mainly described with Figure 2 Different parts.

[0046] As described above, the first operational amplifier 302 and the second operational amplifier 304 may each include a feedback circuit to control the output of the first operational amplifier 302 or the second operational amplifier 304 accordingly. In some embodiments, such as Figure 3 As shown, the first operational amplifier 302 may include a first feedback circuit 306. The first feedback circuit 306 may correspond to... Figure 2 The first feedback circuit 206 shown is described. The first feedback circuit 306 can be... Figure 2 An exemplary implementation of the first feedback circuit 206 shown is illustrated. The first feedback circuit 306 includes resistors R1 and R2. One end of resistor R1 is coupled to the inverting input of the first operational amplifier 302, and the other end of resistor R1 is grounded. One end of resistor R2 is coupled to the inverting input of the first operational amplifier 302, and the other end of resistor R2 is coupled to the first terminal of the scanner 301 (e.g., ...). Figure 3 The left end of the scanner 301 shown is coupled.

[0047] In some embodiments, such as Figure 3 As shown, the second operational amplifier 304 may include a second feedback circuit 307. The second feedback circuit 307 may correspond to... Figure 2 The second feedback circuit 207 shown is described. The second feedback circuit 307 can be... Figure 2 An exemplary implementation of the second feedback circuit 207 shown is illustrated. The second feedback circuit 307 includes resistors R3 and R4. One end of resistor R3 is coupled to the inverting input of the second operational amplifier 304, and the other end of resistor R3 is grounded. One end of resistor R4 is coupled to the inverting input of the second operational amplifier 304, and the other end of resistor R4 is coupled to the second terminal of the scanner 301 (e.g., ...). Figure 3The scanner 301 shown is coupled at the right end.

[0048] As described above, the feedback circuit can be configured based on the control signal corresponding to the input to the first operational amplifier 302 (e.g., the first input signal, via...). Figure 3 The node A input shown is either the control signal (e.g., the second input signal, via) input to the second operational amplifier 304 or the control signal input to the second operational amplifier 304. Figure 3 The node B input shown makes the DC voltage divider across scanner 301 a predetermined value. In this disclosure, the DC voltage divider of scanner 301 can represent the voltage when the voltage difference across scanner 301 is zero.

[0049] In embodiments of this disclosure, if the DC voltage divider across scanner 301 is a predetermined value 'a' and the DC voltage divider of the first input signal is 'b', then the ratio of the resistance values ​​of R1 and R2 is set to be equal to the ratio of b to (ab). Similarly, if the DC voltage divider across scanner 301 is a predetermined value 'a' and the DC voltage divider of the second input signal is 'c', then the ratio of the resistance values ​​of R3 and R4 is set to be equal to the ratio of c to (ac). This ensures that when the DC voltage divider of the first input signal is 'b', the DC voltage divider at the first terminal of scanner 301 is a predetermined value 'a', and the DC voltage divider at the second terminal of scanner 301 is also a predetermined value 'a'. In some embodiments, the drive circuit 300 is symmetrically arranged relative to scanner 301, and the DC voltage divider of the first input signal can be set to be equal to the DC voltage divider of the second input signal, i.e., b = c. In this case, R1, R2, R3, and R4 are set such that R1 / R2 = R3 / R4 = b / (ab).

[0050] In some embodiments of this disclosure, a control signal (e.g., a first input signal or a second input signal) may pass through an RC circuit before being input to operational amplifier 302 or 304, so as to change the voltage input to operational amplifier 302 or 304 according to changes in the control signal. For example Figure 3 As shown, a resistor R11 and a capacitor C4 may be included between node A and the input of the first operational amplifier 302. A resistor R12 and a capacitor C5 may be included between node B and the input of the second operational amplifier 302.

[0051] In some embodiments of this disclosure, resistor R5 can be placed at the output terminal of the first operational amplifier 302 and the first terminal of the scanner 301 (e.g., Figure 3 The resistor R6 can be placed between the output of the second operational amplifier 302 and the second terminal of the scanner 301 (e.g., the left end of the scanner 301). Figure 3The resistor R5 or R6 is positioned between the right end of the scanner 301 shown. Setting the resistor R5 or R6 can make the current change flowing through the scanner 301 smoother and reduce distortion. In some embodiments, the resistor R5 positioned between the output of the first operational amplifier 302 and the first end of the scanner 301 can be the same as the resistor R6 positioned between the output of the second operational amplifier 304 and the second end of the scanner 301, for example, having the same resistance value. In other embodiments, R5 and R6 can be different, for example, having different resistance values.

[0052] In some embodiments, the first power amplifier circuit 303 may be as follows: Figure 3 The Class B power amplifier circuit shown. The second power amplifier circuit 305 can be as follows: Figure 3 The diagram shows a Class B power amplifier circuit. A Class B power amplifier circuit includes PMOS transistors and NMOS transistors. For example, as shown... Figure 3 As shown, the first power amplifier circuit 303 may include an NMOS transistor M1 and a PMOS transistor M2. The second power amplifier circuit 305 may include an NMOS transistor M3 and a PMOS transistor M4. The Class B power amplifier circuits 303 and 305 may be arranged symmetrically with respect to the scanner 301.

[0053] In some embodiments, the PMOS and NMOS transistors in Class B power amplifier circuits 303 and 305 are configured to operate in the linear region. The control signal input to, for example, the first operational amplifier 302 or the second operational amplifier 304 can vary over time (e.g., an SPWM signal, a ramp modulation signal, etc. as described above), causing the output signal (e.g., the output voltage) of the first operational amplifier 302 or the second operational amplifier 304 to also vary over time. This results in different conduction levels and different on-resistances (RDS_ON) of the connected PMOS or NMOS transistors, thereby different drive currents flowing through the scanner 301. Therefore, the scanner 301 can be positioned in a desired operating mode based on the set or selected control signal.

[0054] In some embodiments of this disclosure, operational amplifiers 302 or 304 adjust the output voltage based on input control signals (e.g., a first input signal or a second input signal) to control the on-state (on or off) and on-resistance of the corresponding MOSFETs, thereby changing the voltage at the end of scanner 301. Taking a sine wave as an example, and in some embodiments, the first input signal (input via node A) and the second input signal (input via node B) can be set as SPWM signals with opposite carrier phases. During the positive half-cycle of the first input signal (correspondingly, the second input signal is in the negative half-cycle), as... Figure 3In the circuit shown, M1 and M4 are turned on (for example, M1 and M4 are not fully turned on, but are in the linear operating region), while M2 and M3 are turned off, forming a voltage path V1→M1→scanner 301→M4→V4, creating a specific voltage difference across scanner 301. M1 is in the linear operating region; at different points in the positive half-cycle of the first input signal, according to the MOSFET relationship ID = Gm*VGS (VGS is the gate-source voltage, ID is the drain current, and Gm is the transconductance), different VGS results in different IDs. Similarly, M4 is in the linear operating region; at different points in the negative half-cycle of the second input signal, the current in M4 is different. Therefore, the voltage at each terminal of scanner 301 changes with the corresponding input control signal. For example, when the input control signal is an SPWM signal, the current change in scanner 301 is also sinusoidal.

[0055] Similarly, during the negative half-cycle of the first input signal (correspondingly, during the positive half-cycle of the second input signal), as... Figure 3 In the circuit shown, M2 and M3 are turned on (for example, M2 and M3 are not fully turned on, but are in the linear operating region), while M1 and M4 are turned off, forming a path V3→M3→scanner 301→M2→V2, creating a specific voltage difference across scanner 301. Therefore, during the negative half-cycle of the first signal, the voltage at each end of scanner 301 changes accordingly with the different input control signals.

[0056] As described above, the DC voltage divider across scanner 301 can be set to a predetermined value. In some embodiments, the predetermined value of the DC voltage divider across scanner 301 can be set to a value between the voltage of the PMOS connection and the voltage of the NMOS connection. For example, as... Figure 3 As shown, the drain of NMOS transistor M1 can be connected to voltage V1. The drain of PMOS transistor M2 can be connected to voltage V2. Similarly, the drain of NMOS transistor M3 can be connected to voltage V3. The drain of PMOS transistor M4 can be connected to voltage V4. In some embodiments, V1 can be equal to V3. V2 can be equal to V4. The predetermined value of the DC voltage divider of scanner 301 can be set to a value between V1 and V3 or any value between V2 and V4. By way of example and not limitation, the drain of NMOS transistor M1 can be connected to, for example, a voltage of 5V. The drain of PMOS transistor M2 can be grounded. The predetermined value of the DC voltage divider of scanner 301 can be set to a value between 0 and 5V as needed.

[0057] In some embodiments, the predetermined value of the DC voltage divider of the scanner 301 can be set according to the supply voltage of the scanner 301 and the required swing amplitude of the scanner. For example, if the supply voltage of the scanner 301 is 5V as described above, then the predetermined value can be any voltage within the range of 0V to 5V. The larger the required swing amplitude of the scanner 301, the closer the predetermined value is to half the supply voltage of the scanner 301. For example, when the scanner 301 requires a large swing amplitude, the predetermined value of the DC voltage divider of the scanner 301 can be set to an intermediate value between V1 and V3 or an intermediate value between V2 and V4. For example, when V1 = V2 = 5V and V2 = V4 = 0V (ground), the predetermined value of the DC voltage divider of the scanner 301 can be set to 2.5V or close to 2.5V to ensure that the scanner 301 has sufficient adjustment range during reciprocating motion.

[0058] The above explanation uses the case where the feedback ratios of the feedback circuit 306 of the first operational amplifier 302 and the feedback circuit 307 of the second operational amplifier 304 are the same. However, it should be understood that the feedback ratios can be set differently. For example, when the feedback ratios of feedback circuits 306 and 307 are the same, and the duty cycles of the first and second input signals are the same (e.g., both 50%), the voltage difference across the scanner 301 is zero. As another example, when the feedback ratios of feedback circuits 306 and 307 are different, and the voltage difference across the scanner 301 is zero, the duty cycles of the first and second input signals are different.

[0059] Based on the DC voltage divider of the control signal input to operational amplifiers 302 or 304 (e.g., the DC voltage divider of the first input signal is b or c as described above), the amplitude of the control signal, and the DC voltage divider at the output of operational amplifiers 302 or 304, the maximum current flowing through scanner 301 can be calculated. When the current flowing through scanner 301 is at its maximum, the voltage difference across scanner 301 is at its maximum. For example, if the input voltage of MOSFET M1 is at its maximum and the output voltage of MOSFET M4 is at its minimum, then the maximum current flowing through scanner 301 is also the current flowing through MOSFET M1. Therefore, the peak voltage of operational amplifier 302 (or similarly, operational amplifier 304 can be calculated) should be sufficient to allow MOSFET M1 to carry the aforementioned maximum current. Based on the current flowing through MOSFET M1 and the characteristic curve of MOSFET M1, the gate-source voltage difference VGS of MOSFET M1 can be obtained, thereby allowing the required peak output voltage of operational amplifier 302 (or similarly, operational amplifier 304 can be calculated). The power rails of operational amplifiers 302 or 304 can supply operational amplifiers 302 or 304 with a voltage V5 or V6 not less than the peak voltage, so that scanner 301 can achieve the desired operating state.

[0060] In some embodiments of this disclosure, a capacitor C1 can be provided between the inverting input terminal and the output terminal of the first operational amplifier 302, or a capacitor C2 can be provided between the inverting input terminal and the output terminal of the second operational amplifier 304. Capacitors C1 and C2 can provide a path for high-frequency signals. Therefore, in the event of high-frequency oscillation at the output terminal of operational amplifiers 302 or 304, the output voltage of operational amplifiers 302 or 304 can be clamped to the DC potential of the scanner 301 using capacitors C1 and C2. C1 and C2 can be the same or different.

[0061] In some cases, when the output voltage of operational amplifiers 302 or 304 is near the predetermined value of the DC divider voltage of the scanner, scanner 301 may be in a commutation state, at which point the current flowing through scanner 301 is zero (e.g., M1, M2, M3, and M4 are not conducting). The output voltage of operational amplifiers 302 or 304 may oscillate within a predetermined range of this predetermined voltage value. This may cause high-frequency oscillations at the output voltage of operational amplifiers 302 or 304 at the commutation point, potentially interfering with EMC. Capacitors C1 and C2 can provide a path for this high-frequency signal, reducing the fluctuations in the output voltage of operational amplifiers 302 or 304.

[0062] In some embodiments of this disclosure, the parameters of NMOS M1 and PMOS M2 (or, the parameters of NMOS M3 and PMOS M4) can be selected. For example, the threshold voltage at which NMOS M1 begins to conduct can be set to be less than or equal to the threshold voltage at which PMOS M2 begins to conduct, thereby shortening or avoiding the time during which both M1 and M2 are not conducting. This can reduce or avoid stuttering during scanning commutation of the scanner 301. Similarly, the parameters of NMOS M3 and PMOS M4 can be configured.

[0063] In other embodiments of this disclosure, the output of the first operational amplifier 302 and the first terminal of the scanner 301 (e.g.) can be connected. Figure 3 A resistor R5 can be placed between the output of the second operational amplifier 304 and the second terminal of the scanner 301 (as shown). Figure 3 R6 is set between the right end of the scanner 301 shown. By setting R5 or R6, low-gain feedback can be added to the scanner 301, thereby reducing or avoiding stuttering of the scanner 301 during scanning commutation.

[0064] In some embodiments of this disclosure, a resistor can be provided between the output terminal of operational amplifier 302 or 304 and the control terminal of the corresponding power amplifier circuit 303 or 304. For example, a resistor can be provided between the output terminal of the first operational amplifier 302 and the control terminal of the first power amplifier circuit 303. One end of this resistor is connected to the output terminal of the first operational amplifier 302, and the other end is connected to the gate of MOSFETs M1 and M2. Similarly, a resistor can be provided between the output terminal of the second operational amplifier 304 and the control terminal of the second power amplifier circuit 304. The magnitudes of these two sets of resistors can be the same or different. Providing a resistor between the output terminal of the operational amplifier and the control terminal of the corresponding power amplifier circuit can make the scanning curve of the scanner 301 smoother.

[0065] In some embodiments, such as Figure 3 As shown, resistors can be placed between the output of the first operational amplifier 302 and the gates of MOS transistors M1 and M2, respectively, for example... Figure 3 R7 and R8 are shown in the diagram. R7 and R8 can be the same or different. Similarly, resistors can be placed between the output of the second operational amplifier 304 and the gates of MOSFETs M3 and M4, for example... Figure 3R9 and R10 are shown in the diagram. R9 and R10 can be the same or different. Furthermore, in some embodiments, R7 and R9 can be arranged symmetrically with respect to scanner 301, or R8 and R10 can be arranged symmetrically with respect to scanner 301; for example, R7 and R9 can have the same resistance, or R8 and R10 can have the same resistance. In other embodiments, an asymmetrical arrangement can also be used; for example, R7 and R9 can have different resistances, or R8 and R10 can have different resistances.

[0066] In other embodiments, one or more common resistors may be provided between the output of the first operational amplifier 302 and the gates of MOSFETs M1 and M2. Similarly, one or more common resistors may be provided between the output of the second operational amplifier 304 and the gates of MOSFETs M3 and M4. These two sets of common resistors may be arranged symmetrically with respect to the scanner 301; for example, the two sets of common resistors on both sides of the scanner 301 may have the same resistance.

[0067] In some embodiments, a capacitor C3 can be connected in parallel across the scanner 301. Capacitor C3 can reduce the impact of potential crosstalk signals on the movement of the scanner 301. For example, there may be other circuits on the circuit board where the scanner drive circuit is located, and signals generated in these circuits may crosstalk into the drive coil of the scanner 301 through the wiring between coils on the circuit board. Capacitor C3 can reduce the impact of such crosstalk signals or other possible interference signals on the movement of the scanner 301.

[0068] Some embodiments of this disclosure also provide a scanner device. The scanner device includes a scanner, such as scanner 201 or 301 described above. The scanning device may also include scanner drive circuitry consistent with any embodiment of this disclosure, such as any embodiment of scanner drive circuitry 200 or 300 described above. The scanner drive circuitry is connected to the scanner and configured to drive the scanner to oscillate.

[0069] Some embodiments of this disclosure also provide a lidar. The lidar may include, for example, a combination of... Figure 1 The described lidar 100. In some embodiments, the lidar may include a laser. The laser may include, for example, a combination of... Figure 1 The laser described is configured to emit a laser beam. The lidar may also include a scanner device consistent with any embodiment of this disclosure. The scanner device is configured to change the emission direction of the laser beam.

[0070] It should be understood that although this disclosure primarily describes a drive circuit for a scanner used in a lidar system, the scanner drive circuit according to this disclosure can be used in any other suitable device or apparatus to drive the scanner of that device or apparatus to move and achieve one or more of the technical effects described in this disclosure.

[0071] The vehicles described in this disclosure may include automobiles, trucks, motorcycles, golf carts, off-road vehicles, agricultural vehicles, or any other vehicles described elsewhere herein (e.g., buses, boats, airplanes, helicopters, drones, lawnmowers, bulldozers, submarines, all-terrain vehicles, snowmobiles, aircraft, recreational vehicles, amusement park vehicles, agricultural equipment, construction equipment or vehicles, warehouse equipment or vehicles, factory equipment or vehicles, trams, trains, handcarts, sidewalk delivery vehicles, robotic equipment, etc.).

[0072] Therefore, those skilled in the art can make appropriate modifications and adjustments to the embodiments specifically described above without departing from the spirit of this disclosure. Thus, it is intended that the claimed subject matter not be limited to the specific examples disclosed, but also include all implementations falling within the scope of the appended claims and their equivalents.

Claims

1. A scanner driver circuit, characterized in that, include: A first operational amplifier, wherein the input terminal of the first operational amplifier is configured to receive a first input signal; A first power amplifier circuit, wherein a first terminal of the first power amplifier circuit is configured to be coupled to the output terminal of the first operational amplifier, and a second terminal of the first power amplifier circuit is configured to be coupled to the first terminal of the scanner; A second operational amplifier, the input of which is configured to receive a second input signal; as well as A second power amplifier circuit, wherein a first terminal of the second power amplifier circuit is configured to be coupled to the output terminal of the second operational amplifier, and a second terminal of the second power amplifier circuit is configured to be coupled to the second terminal of the scanner. The first operational amplifier and the second operational amplifier include a feedback circuit, which is configured to make the DC voltage across the scanner a predetermined value based on the corresponding first input signal or the second input signal.

2. The scanner driving circuit as described in claim 1, characterized in that, The first operational amplifier includes a first feedback circuit, which includes: A first resistor, the first end of which is coupled to the inverting input of the first operational amplifier, and the second end of which is grounded; and The second resistor has a first end coupled to the inverting input of the first operational amplifier and a second end coupled to the first end of the scanner.

3. The scanner driving circuit as described in claim 1, characterized in that, The second operational amplifier includes a second feedback circuit, which includes: A third resistor, the first end of which is coupled to the inverting input of the second operational amplifier, and the second end of which is grounded; and A fourth resistor, the first end of which is coupled to the inverting input of the second operational amplifier, and the second end of which is coupled to the second end of the scanner.

4. The scanner driving circuit as described in claim 2 or claim 3, characterized in that, The resistance values ​​of the first resistor, the second resistor, the third resistor, and the fourth resistor meet at least one of the following conditions: The ratio of the resistance values ​​of the second resistor and the first resistor is equal to the ratio of the difference between the predetermined value and the DC voltage of the first input signal to the DC voltage of the first input signal; or, The ratio of the resistance values ​​of the fourth resistor and the third resistor is equal to the ratio of the difference between the predetermined value and the DC voltage of the second input signal to the DC voltage of the second input signal.

5. The scanner driving circuit as described in claim 1, characterized in that, It also includes at least one of the following: A fifth resistor is disposed between the output terminal of the first operational amplifier and the first terminal of the scanner; or, A sixth resistor is provided between the output of the second operational amplifier and the second terminal of the scanner.

6. The scanner driving circuit as described in claim 1, characterized in that, The first power amplifier circuit and the second power amplifier circuit include Class B power amplifier circuits, wherein the Class B power amplifier circuits include PMOS and NMOS, and the PMOS and NMOS are configured to operate in the linear region.

7. The scanner driving circuit as described in claim 6, characterized in that, The predetermined value of the DC voltage divider of the scanner is set to the midpoint between the first voltage of the PMOS connection and the second voltage of the NMOS connection.

8. The scanner driving circuit as described in claim 6, characterized in that, The first threshold voltage at which the NMOS begins to conduct is configured to be less than or equal to the second threshold voltage at which the PMOS begins to conduct.

9. The scanner driving circuit as described in claim 1, characterized in that, At least one of the following: A first capacitor is disposed between the inverting input terminal and the output terminal of the first operational amplifier; or, A second capacitor is disposed between the inverting input terminal and the output terminal of the second operational amplifier.

10. The scanner driving circuit as described in claim 1, characterized in that, It also includes at least one of the following: A seventh resistor is disposed between the output terminal of the first operational amplifier and the control terminal of the first power amplifier circuit; or, An eighth resistor is placed between the output terminal of the second operational amplifier and the control terminal of the second power amplifier circuit.

11. The scanner driving circuit as described in claim 1, characterized in that, It also includes a third capacitor, which is configured to be connected in parallel with the scanner.

12. The scanner driving circuit as described in claim 1, characterized in that, The carrier phases of the first input signal and the second input signal are opposite.

13. A scanner device, characterized in that, include: Scanner, and The scanner driving circuit according to any one of claims 1-12, wherein the scanner driving circuit is connected to the scanner and configured to drive the scanner to oscillate.

14. A lidar, characterized in that, include: A laser, configured to emit a laser beam; as well as The scanner device of claim 13, wherein the scanner device is configured to change the emission direction of the laser beam.

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