Boost soft charging circuit for driving laser emission, laser radar and charging method thereof

Abstract

According to the boost soft charging circuit for driving laser emission, the laser radar and the charging method of the laser radar, the boost soft charging circuit comprises an input port, an output port and a charging circuit connected between the input port and the output port, and the charging circuit comprises a first switching circuit and an energy storage inductor. The first switch circuit responds to a first driving signal and conducts the input port and the output port so as to enable the energy storage inductor to store energy; after the laser transmitter is triggered, energy stored in the energy storage inductor is efficiently transferred to the bus capacitor by utilizing the resonance characteristics of the inductor and the capacitor, so that the bus capacitor is charged until the voltage on the power bus reaches the working voltage of the laser transmitter. According to the resonant charging mode, energy loss in the charge sharing process can be avoided, the energy transmission efficiency is improved, and system heating is effectively reduced; and moreover, the limitation on the bus capacitance is reduced, and the circuit is simple in structure, reliable and stable.

Description

Technical Field

[0001] This application relates to the technical field of lidar driving, and particularly to a boost soft charging circuit for driving laser emission, a lidar, and a charging method thereof. Background Art

[0002] With the development of electric vehicles, the rapid development of the Advanced Driver Assistance System (ADAS) has made the importance of lidar (LiDAR) technology increasingly prominent. Lidar works based on the Time of Flight (ToF) principle, and it is indispensable for achieving accurate environmental perception in automotive sensor systems. To meet the stringent requirements of future vehicles for detection range and accuracy, lidar transmitters require drive currents with specific performance. Generally, the drive current needs to have a nanosecond-level pulse width and an amplitude reaching dozens of amperes. This means that lidar systems not only require high-voltage power supplies to ensure sufficient power output for long-distance detection but also require fast charging speeds and low charging losses to meet the needs of high-frequency pulse emission.

[0003] In the prior art, a commonly adopted method is to connect a current-limiting resistor between the output capacitor of the boost converter and the bus capacitor of the laser drive circuit to achieve the charging process of the bus capacitor. However, this traditional method has many deficiencies. Specifically, on the one hand, the boost converter requires a large-volume output capacitor with a high-voltage and large capacitance value and a high-power current-limiting resistor, which undoubtedly increases the cost and volume of the system; on the other hand, when the bus capacitor is replenished with energy through the output capacitor of the boost converter, due to the large voltage difference between the two capacitors, significant energy losses will occur during the charge sharing process, which will greatly reduce the system efficiency and also generate more heat; to solve the energy consumption problem, a more powerful thermal management system needs to be equipped, which also increases the system cost, volume, and complexity. Summary of the Invention

[0004] This application provides a boost soft charging circuit for driving laser emission, a lidar, and a charging method thereof, which can solve the technical problems that the boost charging circuit for providing the drive voltage of the laser transmitter in the traditional lidar system has the restriction of low bus voltage on system performance and additional energy losses will occur during the charging of the bus capacitor.

[0005] In a first aspect, an embodiment of this application provides a boost soft charging circuit for driving laser emission, including:

[0006] An input port for connecting to an external input power supply to obtain an input voltage;

[0007] An output port for connecting to a laser transmitter through a power bus to provide a working voltage to the laser transmitter; wherein, a bus capacitor is connected between the power bus and a preset voltage terminal;

[0008] A charging circuit is connected between the input port and the output port; the charging circuit includes a first switching circuit and a storage inductor; the first switching circuit conducts the input port and the output port in response to a first level of a first driving signal; the storage inductor is configured to, after the laser emitter is triggered and when the first switching circuit is conducting, form a resonant circuit with the bus capacitor to charge the bus capacitor until the voltage on the power bus reaches the operating voltage of the laser emitter.

[0009] In some embodiments, the first switching circuit is further configured to, when the voltage on the bus capacitor reaches the operating voltage of the laser emitter, respond to a second level of the first driving signal to disconnect the input port from the output port, so that the storage inductor stops charging the bus capacitor.

[0010] In some embodiments, when the voltage on the bus capacitor reaches the input voltage of the input port, the first driving signal will switch from the first level to the second level.

[0011] In some embodiments, the first switching circuit includes a first switching transistor; the control end of the first switching transistor is configured to obtain the first driving signal, the first end of the first switching transistor is connected to the input end of the charging circuit to obtain the input voltage; the first end of the storage inductor is connected to the second end of the first switching transistor, and the second end of the storage inductor is connected to the output end of the charging circuit.

[0012] In some embodiments, the charging circuit further includes a first diode; the first end of the first diode is connected to the second end of the storage inductor, and the second end of the first diode is connected to the output end of the charging circuit.

[0013] In some embodiments, the boost soft charging circuit for driving laser emission further includes a charging current return circuit;

[0014] The charging current return circuit is connected between the input port and the preset voltage terminal and is connected in series with the first switching circuit; the charging current return circuit is configured to, after the storage inductor stops charging the bus capacitor, form a loop with the input port and the preset voltage terminal to return the current of the storage inductor to the input port until the current on the storage inductor is zero.

[0015] In some embodiments, the charging current return circuit includes a second switching transistor, a third switching transistor, and a second diode;

[0016] The control terminal of the second switching tube is used to obtain a second driving signal. The first end of the second switching tube is connected to the second end of the energy storage inductor, and the second end of the second switching tube is connected to the input port; the control terminal of the third switching tube is used to obtain a third driving signal. The first end of the third switching tube is connected to the first end of the energy storage inductor, and the second end of the third switching tube is connected to the preset voltage terminal;

[0017] The second diode is used to block the reverse current between the input port and the energy storage inductor when the circuit on the energy storage inductor is zero; the second diode is connected between the first end of the second switching tube and the second end of the energy storage inductor.

[0018] In some embodiments, the inductance value parameter of the energy storage inductor satisfies that the time when the current of the energy storage inductor flows into the bus capacitor exceeds one-quarter of the resonance period.

[0019] In a second aspect, an embodiment of the present application provides a lidar, including: a boost soft charging circuit for driving laser emission, a power bus, and a laser emission circuit as described in any of the above embodiments; a bus capacitor and a parasitic inductor are connected between the power bus and the preset voltage terminal;

[0020] The laser emission circuit includes a laser emitter and a trigger circuit; the laser emitter emits laser in response to a trigger signal sent by the trigger circuit; wherein, when the laser emitter emits laser, a resonance discharge loop formed by the bus capacitor and the parasitic inductor provides a laser driving current;

[0021] The boost soft charging circuit is used to charge the bus capacitor through a resonance charging loop formed by the energy storage inductor and the bus capacitor after the laser emitter emits laser until the voltage on the power bus reaches the working voltage of the laser emitter.

[0022] In a third aspect, an embodiment of the present application provides a charging method for a lidar, which is used for the lidar described in any of the above embodiments; the charging method includes:

[0023] Monitoring the state of the laser emitter;

[0024] After determining that the laser emitter emits laser, controlling the boost soft charging circuit for driving laser emission to charge the bus capacitor until the voltage on the bus capacitor reaches the working voltage of the laser emitter.

[0025] The boost soft charging circuit for driving laser emission, lidar and its charging method provided by the embodiments of the present application. The boost soft charging circuit includes an input port, an output port, and a charging circuit connected between the input port and the output port. The charging circuit at least includes a first switching circuit and a storage inductor. The first switching circuit responds to a first driving signal to conduct the input port and the output port, so that the storage inductor stores energy. After the laser emitter is triggered, using the resonance characteristics of the inductor and capacitor, the energy stored in the storage inductor is efficiently transferred to the bus capacitor to charge the bus capacitor until the voltage on the power bus reaches the operating voltage of the laser emitter. The resonance charging method adopted in the present application can avoid energy loss during the charge sharing process, improve the energy transfer efficiency, and effectively reduce system heating; and reduce the limitation on the size of the bus capacitor, and the circuit structure is simple, reliable and stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings herein are incorporated into and constitute a part of this specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0027] Figure 1 FIG. is a schematic structural diagram of a boost soft charging circuit for driving laser emission provided by an embodiment of the present application.

[0028] Figure 2 FIG. is a schematic structural diagram of a boost soft charging circuit for driving laser emission provided by another embodiment of the present application.

[0029] Figure 3 FIG. is a circuit diagram of a boost soft charging circuit for driving laser emission provided by an embodiment of the present application.

[0030] Figure 4 FIG. is a circuit diagram of a lidar provided by an embodiment of the present application.

[0031] Figure 5 FIG. is a process diagram of the operation of a boost soft charging circuit provided by an embodiment of the present application.

[0032] Figure 6 FIG. is a waveform diagram of the operation process of a boost soft charging circuit provided by an embodiment of the present application.

[0033] Figure 7 FIG. is a flowchart of a charging method for a lidar provided by an embodiment of the present application.

[0034] Through the above-mentioned accompanying drawings, specific embodiments of the present application have been shown, and there will be more detailed descriptions hereinafter. These drawings and text descriptions are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. Detailed implementation manners

[0035] The present application will be further described in detail below in conjunction with the accompanying drawings through specific implementation manners. Similar elements in different implementation manners use related similar element numbers. In the following implementation manners, many detailed descriptions are provided to enable a better understanding of the present application. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other elements, materials, or methods. In some cases, some operations related to the present application are not shown or described in the specification to avoid overwhelming the core part of the present application with excessive descriptions. For those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations based on the descriptions in the specification and the general technical knowledge in the art.

[0036] In addition, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various implementation manners. At the same time, the steps or actions in the method description can also be reordered or adjusted in a manner obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for clearly describing a certain embodiment and do not mean a necessary sequence, unless it is stated otherwise that a certain sequence must be followed.

[0037] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects and are not used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are usually of the same type, and the number of objects is not limited. For example, the first object can be one or multiple. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / " generally indicates an "or" relationship between the associated objects before and after. And the "connection" and "coupling" mentioned in the present application, unless otherwise specified, both include direct and indirect connection (coupling).

[0038] The technical solution of the present application and how the technical solution of the present application solves the above technical problems will be described in detail below with specific embodiments. These several specific embodiments below can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0039] Figure 1 It is a schematic structural diagram of a boost soft charging circuit for driving laser emission provided by an embodiment of the present application. As Figure 1As shown, the boost soft charging circuit for driving laser emission provided in this embodiment at least includes an input port 110, an output port 120, and a charging circuit 130 connected between the input port 110 and the output port 120.

[0040] In this embodiment, the input port 110 is the connection point of the circuit to an external power supply to obtain an input voltage. Through a conductive channel, the input port 110 can transmit the input voltage to various parts of the circuit, including the charging circuit 130 and a possible protection circuit.

[0041] The output port 120 is the output interface of the boost soft charging circuit 130, which is directly connected to the laser emitter through a power bus, and is responsible for stably and efficiently transmitting the processed electrical energy to the laser emitter to ensure that the laser emitter can work normally and efficiently. A bus capacitor C is connected between the power bus and a preset voltage terminal (the preset voltage terminal can be the ground terminal in the circuit, which may be a reference ground or an actual ground terminal). Bus , which can smooth the fluctuations of the input voltage. When the voltage of the external input power supply changes, the bus capacitor C Bus can absorb or release charges, thereby maintaining the relative stability of the voltage on the power bus, reducing circuit failures caused by power voltage fluctuations, and protecting other components in the circuit from voltage shocks.

[0042] The charging circuit 130 is the core part of the boost soft charging circuit, which is responsible for converting and storing the electrical energy received by the input port 110 and providing it to the laser emitter through the output port 120 in a suitable manner when needed.

[0043] In this embodiment, the charging circuit 130 at least includes a first switch circuit and a storage inductor L. Usually, the first switch circuit consists of a semiconductor switching device (such as MOSFET, IGBT, etc.) and its control circuit. The first switch circuit responds to the first level (usually high level) of the first drive signal, and the switch circuit conducts, thereby connecting the input port 110 (i.e., the external input power supply) to the output port 120 (i.e., the subsequent load circuit, the laser emitter), enabling the electrical energy of the external input power supply to flow through the switch circuit and enter the storage inductor L.

[0044] After the laser emitter emits laser, the voltage on the power bus is at a very low value, so there is a certain positive voltage difference across the storage inductor L, and the inductor magnetization starts. At this time, the inductor current continuously flows into C Bus , and the bus voltage continuously rises. When the bus voltage is greater than the voltage provided by the input port 110, a negative voltage difference appears across the storage inductor L, and the magnetic energy in the inductor is released. Throughout the process, the input port 110 always supplies energy to the power bus through the charging circuit 130. Directly through the storage inductor L to the bus capacitor C BusCharging can avoid energy loss during the charge sharing process. Under ideal conditions, charge is transmitted without loss, thereby improving the energy transfer efficiency and effectively reducing system heating. At the same time, the charging time is also shortened, making the charging cycle of the energy storage inductor L and the bus capacitor C Bus almost proportional to the charging time. During the operation of the transmitter, the current in the energy storage inductor L remains almost constant. Even if the inductance value is small, the interference to the resonant charging process can be ignored.

[0045] It should be noted that the basic structure of the soft charging circuit in this embodiment is similar to that of the traditional Boost charging circuit, and both at least include an energy storage inductor L and a bus capacitor C Bus , but the charging circuit 130 in this embodiment uses the energy storage inductor L and the bus capacitor C Bus to form a resonant circuit for charging, which is significantly different from the existing Boost charging circuit. In this embodiment, by utilizing the resonant characteristics of the inductor and the capacitor, efficient conversion and storage of energy can be achieved without loss between the energy storage inductor L and the bus capacitor C Bus . The traditional Boost charging circuit boosts the input voltage to a higher output voltage through periodic switching operations of switching elements (such as transistors). When the switching element is turned off, the energy storage inductor L stores energy; when the switching element is turned on, the energy storage inductor L releases the stored energy, increasing the output voltage. However, this method requires a large output capacitor to store the output voltage, and then charges the bus capacitor through a current limiting resistor. This intermediate process of energy conversion is essentially a hard charging process of capacitor to capacitor, with significant energy loss. Compared with traditional technologies, the resonant charging circuit in this embodiment has the advantages of high efficiency, fast charging, good stability, and no intermediate process, can achieve efficient conversion and storage of energy, reduce energy loss, the electrical energy in the circuit can be more effectively converted into charge, and can adapt to different input voltages and charging requirements by adjusting the parameters of the energy storage inductor L and the bus capacitor C Bus , so it is more suitable for scenarios that require high efficiency, fast charging, and stable performance.

[0046] Also because the charging circuit 130 in this embodiment uses the energy storage inductor L and the bus capacitor C Bus to form a resonant circuit for charging, soft charging of the laser emission driving circuit is achieved, that is, the charging process is not sudden and instantaneous, but gradually changes with the smooth change of the inductor current, which can reduce the current impact and voltage fluctuation in the circuit and protect the components in the circuit from damage. Only by adjusting the parameters of the energy storage inductor L and the bus capacitor C Bus to control the rising rate of the charging current and voltage, the characteristic of adjusting the charging speed can be achieved. At this time, the energy storage inductor L charges the bus capacitor C BusThe charging process can be regarded as a soft charging process with a nearly unobstructed component.

[0047] In addition, the charging circuit 130 of this embodiment is based on the energy storage inductor L and the bus capacitor C Bus to form a resonant circuit for charging. The energy storage inductor L and the bus capacitor C Bus jointly determine the resonant frequency. Generally, the higher the resonant frequency, the smaller the required capacitance value; conversely, the lower the resonant frequency, the larger the required capacitance value. For a common laser emitter circuit, the capacitance value of the required bus capacitor C Bus is generally in the nF range. In capacitive resonant drive, when a low bus voltage is used, in order to increase the pulse peak to detect a long-distance target, a relatively large bus capacitor C Bus is usually required. However, a larger capacitor will cause the pulse width to become wider, reducing the detection accuracy, and at the same time increasing the average emission energy of the laser, posing a threat to human eye safety. This embodiment uses resonant boost technology to effectively increase the bus voltage; and under the condition of a high bus voltage, the capacitance value requirement for the bus capacitor C Bus can be significantly reduced. While maintaining the pulse peak level, it can also effectively compress the pulse width, reduce the average laser emission energy, and ensure human eye safety. In addition, a higher pulse peak also improves the adaptability of the system in harsh weather or low reflectivity target scenarios, ensuring that the returned signal has a high signal-to-noise ratio.

[0048] In some embodiments, the first switch circuit is further configured to, when the voltage on the bus capacitor C Bus reaches the operating voltage of the laser emitter, respond to the second level of the first drive signal, disconnect the input port 110 from the output port 120, and adjust the current flow direction of the energy storage inductor L to stop the energy storage inductor L from charging the bus capacitor C Bus .

[0049] In some embodiments, when the voltage on the bus capacitor C Bus reaches the input voltage of the input port 110, the first drive signal will switch from the first level to the second level.

[0050] In the above embodiments, the first drive signal for controlling the first switch circuit has two levels, where the first level and the second level can be a high level and a low level, and the on and off of the first switch circuit are controlled by the switching of the levels. In some embodiments, two different drive signals can also be used as instructions to control the on and off of the first switch circuit.

[0051] Figure 2 It is a schematic structural diagram of a boost soft charging circuit for driving laser emission provided by another embodiment of the present application. As Figure 2As shown in the figure, the boost soft charging circuit for driving laser emission provided in this embodiment at least includes an input port 110, an output port 120, a charging circuit 130 connected between the input port 110 and the output port 120, and a charging return circuit 140. Among them, the connection relationship and implementation process of the input port 110, the output port 120, and the charging circuit 130 connected between the input port 110 and the output port 120 are similar to those in the above embodiment. To avoid repetition, they will not be elaborated here.

[0052] In this embodiment, the charging return circuit is connected between the input port 110 and the preset voltage terminal and is connected in series with the first switch circuit. The charging return circuit is used to, after the energy storage inductor L stops charging the bus capacitor C Bus form a loop with the input port 110 and the preset voltage terminal, so that the current on the energy storage inductor L returns to the input port 110 until the current on the energy storage inductor L becomes zero. That is to say, the charging return circuit, the first switch circuit, and other components they are connected to together form a complete circuit path that can control the flow direction of electric energy. When the energy storage inductor L completes the charging process of the bus capacitor C Bus and the first switch circuit has disconnected the connection between the input port 110 and the output port 120 (i.e., the connection between the energy storage inductor L and the bus capacitor C Bus ), the charging return circuit starts to function. At this time, the energy storage inductor L, the charging return circuit, the input port 110, and the preset voltage terminal form a closed current path, aiming to flow the remaining electric energy in the energy storage inductor L in the form of current and finally release this energy. When the current on the energy storage inductor L drops to zero, it means that the energy storage inductor L has completely released the electric energy it stores and is ready to enter the next charging cycle. By cooperating with the first switch circuit and the energy storage inductor L, the charging return circuit can ensure that after the energy storage inductor L stops charging the bus capacitor C Bus the remaining electric energy is effectively released, thus maintaining the stability and efficiency of the system.

[0053] Figure 3 This is the circuit diagram of the boost soft charging circuit for driving laser emission provided by an embodiment of the present application. As Figure 3 shown, the boost soft charging circuit for driving laser emission provided in this embodiment at least includes an input port 110, an output port 120, a charging circuit 130 connected between the input port 110 and the output port 120, and a charging return circuit 140.

[0054] In this embodiment, the charging circuit 130 includes a first switch circuit and an energy storage inductor L; among them, the first switch circuit includes a first switch tube S 1 ; the first switch tube S 1The control terminal is used to obtain the first driving signal, and the first switching transistor S 1 The first terminal of is connected to the input terminal of the charging circuit 130, that is, connected to the input port 110 to obtain the input voltage. The first switching transistor S 1 The second terminal of is connected to the first terminal of the energy storage inductor L. The second terminal of the energy storage inductor L is connected to the output terminal of the charging circuit 130, that is, connected to the output port 120 to provide the working voltage to the laser emitter.

[0055] In some embodiments, the charging circuit 130 further includes a first diode D 1 . Specifically, the first terminal of the first diode is connected to the second terminal of the energy storage inductor L, and the second terminal of the first diode is connected to the output terminal of the charging circuit 130. That is, the first diode D 1 is connected between the energy storage inductor L and the output port 120 to prevent current backflow.

[0056] In this embodiment, the charging reflux circuit includes a second switching transistor S 2 and a third switching transistor S 3 . Specifically, the control terminal of the second switching transistor S 2 is used to obtain the second driving signal. The first terminal of the second switching transistor S 2 is connected to the second terminal of the energy storage inductor L, and the second terminal of the second switching transistor S 2 is connected to the input port 110; the control terminal of the third switching transistor S 3 is used to obtain the third driving signal. The first terminal of the third switching transistor S 3 is connected to the first terminal of the energy storage inductor L, and the second terminal of the third switching transistor S 3 is connected to the preset voltage terminal.

[0057] In some embodiments, the charging reflux circuit further includes a second diode D 2 , which is used to block the reverse current between the input port 110 and the energy storage inductor L when the current on the energy storage inductor L is zero; the second diode D 2 is connected between the first terminal of the second switching transistor S 2 and the second terminal of the energy storage inductor L.

[0058] In some embodiments, the inductance value parameter of the energy storage inductor satisfies that the time when the current of the energy storage inductor flows into the bus capacitor exceeds one-fourth of the resonance period to control the time of the charging process. At the same time, it can also make the recovery time of the bus voltage proportional to the resonance period. That is to say, the voltage recovery time of the bus capacitor C Bus can be adjusted by the inductance value of the energy storage inductor L. When the time when the current of the energy storage inductor L flows into the bus capacitor C Bus exceeds one-fourth of the energy storage inductor L and the bus capacitor C BusWhen the resonant period is reached, the boost function can be achieved; at the same time, the bus voltage V Bus The recovery time is proportional to the resonant period.

[0059] In summary, the boost soft charging circuit for driving laser emission provided in this embodiment, through the cooperation of the charging circuit and the charging return circuit with the energy storage inductor L, the switching tube in the charging circuit, under the control of the first driving signal, enables the energy storage inductor L and the bus capacitor C Bus to form a resonant circuit, and utilizes the resonant characteristics of the inductor and capacitor to charge the bus capacitor C Bus ; and after the charging is completed, the charging circuit is disconnected and the charging return circuit is turned on, so that the energy storage inductor L releases energy, introducing an energy recovery mechanism, improving the system energy efficiency and significantly reducing the power consumption; that is, the soft charging control of the bus capacitor C of the laser transmitter is realized, improving the charging efficiency and system performance, and can also flexibly control the time of the charging process by adjusting the parameters of the energy storage inductor L, achieving a balance between the charging speed and efficiency. Bus

[0060] Figure 4 This is the circuit diagram of a lidar provided by an embodiment of the present application. As Figure 4 shown, the lidar provided in this embodiment includes the boost soft charging circuit for driving laser emission, the power bus, and the laser emission circuit described in any of the above embodiments.

[0061] In this embodiment, a bus capacitor C Bus and a parasitic inductor are connected between the power bus and the preset voltage terminal. The laser emission circuit includes a laser emitter and a trigger circuit; the laser emitter emits laser in response to the trigger signal issued by the trigger circuit; wherein, when the laser emitter emits laser, a resonant discharge circuit composed of the bus capacitor C Bus and the parasitic inductor provides the working voltage; the boost soft charging circuit is used to charge through a resonant charging circuit composed of the energy storage inductor L and the bus capacitor C Bus after the laser emitter emits laser, until the voltage on the bus reaches the working voltage of the laser emitter.

[0062] In some embodiments, the laser emitter may be a laser diode D L , and the trigger circuit includes an emission switch tube S Emit .

[0063] Next, in combination with the circuit diagram of the above lidar, the working principle of the boost soft charging circuit 410 in the present application will be further described.

[0064] Figure 5 This is the process diagram of the operation of the boost soft charging circuit provided by an embodiment of the present application. Figure 6This is a waveform diagram of the operation process of a boost soft charging circuit provided by an embodiment of the present application. As Figure 5 and Figure 6 shown, based on the circuit diagram of the boost soft charging circuit provided by the above embodiment, the operation process of the boost soft charging circuit includes at least four stages, namely the laser emission stage (Φ E ), the bus capacitor charging stage (Φ C ), the bus voltage regulation stage (inductor current recovery stage, Φ R ), and the waiting for emission stage (Φ S ).

[0065] In the laser emission stage (Φ E ), when the control terminal of the emission switch S Emit receives the emission control signal V launch and is triggered, the emission switch S Emit will conduct rapidly, and the laser diode D L enters the forward bias state, and at the same time, the equivalent parasitic inductor L stray is excited. At this time, the resonant current pulse I DL causes the bus capacitor C Bus to discharge, and its bus voltage V Bus drops to 2V DL -V TG , where V DL is the forward bias voltage of the laser diode D L , and V TG is the desired bus voltage V Bus value. During this entire stage, the time is very short, and the change amplitude of the current I L on the energy storage inductor L is extremely small and can be almost ignored.

[0066] In this stage, the discharge resonance causes the voltage V Bus on the bus capacitor C Bus to become negative. At this time, a large pressure difference is generated across the energy storage inductor L, providing conditions for the magnetization of the energy storage inductor L, thereby starting the resonant charging process between the energy storage inductor L and the bus capacitor C Bus .

[0067] In the bus capacitor charging stage (Φ C ), the first switching tube S 1 conducts under the control of the first drive signal. Since the bus voltage V Bus drops to 2V DL -V TG during the laser emission stage, an L-C Bus resonant circuit between the energy storage inductor L and the bus capacitor C Bus is successfully established. In this circuit, the energy storage inductor L starts to be magnetized sharply. AsFigure 6 As shown, from time t 2 to time t 4 . During this period, the resonant current continuously charges the bus capacitor C Bus . When the time reaches t 4 , the voltage value of the bus voltage V Bus exceeds the input voltage V IN . At this time, although the current I L of the energy storage inductor L begins to decrease, it still continues to provide a charging current for the bus voltage V Bus , making it higher than V IN .

[0068] In this stage, as the current I L of the energy storage inductor L gradually rises, all the current flows into the bus capacitor C Bus for charging, and the bus voltage V Bus keeps rising. As Figure 6 shown, the rising slope of the current I L of the energy storage inductor L gradually decreases with the increase of the bus voltage V Bus , until the voltage across the energy storage inductor L is zero. At this time, the slope of the current I L of the energy storage inductor L is zero, reaching a quarter of the resonance period. Subsequently, the current I L of the energy storage inductor L begins to decrease, but the bus voltage V Bus still continues to rise. By precisely controlling the time when the current I L of the energy storage inductor L flows into the bus capacitor C Bus , the final bus voltage V Bus can be adjusted. As long as the time when the current I L of the energy storage inductor L flows into the bus capacitor C Bus exceeds a quarter of the resonance period, the bus voltage V Bus will be greater than the input source voltage V IN , thus achieving step-up.

[0069] It can be seen that on the charging path in this stage, only the on-resistance of the switch, the parasitic resistance of the energy storage inductor L and the bus capacitor C Bus and the parasitic resistance of the wire exist. Due to the very small resistance, the charging process of the energy storage inductor L to the bus capacitor C Bus can be approximated as an ideal inductor-capacitor resonance process. Different from the hard charging method of the inductor to the capacitor in the traditional scheme, through the soft charging of the energy storage inductor L to the bus capacitor C Bus , the energy loss in this process is extremely small. The first diode D 1 on the charging path ensures that the current I L of the energy storage inductor L will not flow reversely during the resonant charging process.

[0070] During the bus voltage regulation phase (Φ R ), in order to accurately regulate the bus voltage V Bus to the target level V TG , this active regulation phase is introduced. During this phase, the first switching transistor S 1 is turned off, while the second switching transistor S 2 and the third switching transistor S 3 are simultaneously activated and turned on. This switching state change causes the current I L of the energy storage inductor L to no longer charge the bus capacitor C Bus , but instead flow back to the input side, realizing the recovery of the residual energy in the energy storage inductor L, further reducing the overall energy loss and improving the system efficiency. By cleverly controlling the start time of this phase, the bus voltage V Bus can be effectively regulated to the target level. As Figure 6 shown, throughout this phase, the current I L of the energy storage inductor L gradually decreases at a fixed linear rate.

[0071] During this phase, by controlling the charging time of the bus capacitor C Bus within a quarter to half of the resonant period, the boost function is achieved. The recovery time of the bus voltage V Bus will also be proportional to the resonant period. By reducing the value of the energy storage inductor L, the resonant period can be shortened, and thus a faster bus voltage recovery can be achieved. Moreover, since the discharge resonant period during laser emission is much smaller than the charging resonant period, even if the value of the energy storage inductor L is reduced, it will not affect the emission process of the laser emitter, and the current I L of the energy storage inductor L rises very little during the laser emission process and will not interfere with the emission process.

[0072] During the waiting for emission phase (Φ S ), when the current I L of the energy storage inductor L gradually decreases to 0, the second diode D 2 will automatically block the reverse current path, marking the successful end of a complete working cycle. At this time, the system smoothly enters the emission standby phase, and all components in the circuit are in a ready state, waiting for the trigger signal for the next laser pulse emission.

[0073] Figure 7 is a flowchart of a charging method for a lidar provided by an embodiment of the present application. As Figure 7 shown, the charging method for the lidar provided by this embodiment is applied to the above-mentioned lidar with a boost soft charging circuit. The charging method for this lidar includes the following steps:

[0074] Step S710, monitor the state of the laser emitter;

[0075] Step S720: After determining that the laser emitter emits laser light, control the boost soft charging circuit for driving laser emission to charge the bus capacitor until the voltage on the bus capacitor reaches the operating voltage of the laser emitter.

[0076] Specifically, the bus capacitor C Bus and the parasitic inductance L resonate and discharge to drive the laser emitter to emit laser light. When the laser emitter is triggered to emit light, the bus capacitor C Bus and the parasitic inductance L stray form a resonant discharge loop to provide drive current for the laser emitter, while pulling down the bus voltage V Bus , and the low bus voltage V Bus causes a voltage difference across the energy storage inductor, thus establishing an L-C Bus resonance process between the energy storage inductor L and the bus capacitor C Bus . The negative bus voltage generated during the resonant discharge drive process provides the initial condition for the resonant charging process of the bus capacitor C Bus and the energy storage inductor L. During the resonance process, the energy storage inductor L starts to be magnetized rapidly, and the boost soft charging circuit charges the bus capacitor C Bus . As the current I L of the energy storage inductor L gradually rises and all the current flows into the bus capacitor C Bus , the bus voltage V Bus keeps rising. After the bus voltage V Bus is adjusted to the operating voltage of the laser emitter, the first switch circuit in the boost soft charging circuit can be controlled to turn off through the first drive signal, and the charging of the bus capacitor C Bus is stopped. At this time, the bus voltage V Bus finally becomes negative, and the resonant discharge drive process ends.

[0077] In some embodiments, after stopping the charging of the bus capacitor C Bus , the circuit of the energy storage inductor L is switched through the second drive signal and the third drive signal, so that the current I L of the energy storage inductor L flows back to the input side, realizing the recovery of the residual energy in the energy storage inductor L, further reducing the overall energy loss, and improving the system efficiency.

[0078] The specific working process is as described in any of the above embodiments. To avoid repetition, it will not be elaborated here.

[0079] The charging method of the lidar provided in this embodiment is based on a boost soft charging circuit. Through the cooperation of the charging circuit and the charging return circuit with the energy storage inductor L, after the laser emitter emits laser light, an L-C Bus resonant circuit is formed between the energy storage inductor L and the bus capacitor C, and the resonant characteristics of the inductor and capacitor are utilized to realize the charging of the bus capacitor CBus Charging; and after charging is completed, disconnecting the charging circuit and conducting the charging reflux circuit, enabling the energy storage inductor L to release energy, introducing an energy recovery mechanism, improving the system energy efficiency and significantly reducing power consumption; that is, realizing soft charging control of the laser transmitter bus capacitor C Bus improves the charging efficiency and system performance, and can also flexibly control the time of the charging process by adjusting the parameters of the energy storage inductor L, achieving a balance between the charging speed and efficiency.

[0080] The embodiments of the present application have been described above in conjunction with the accompanying drawings. However, the present application is not limited to the above specific embodiments. The above specific embodiments are merely illustrative and not restrictive. Those of ordinary skill in the art, under the inspiration of the present application, without departing from the purpose of the present application and the scope protected by the claims, can make several simple deductions, deformations or substitutions according to the idea of the present application, all of which fall within the protection scope of the present application.

Claims

1. A boost soft charging circuit for driving laser emission, characterized in that: include: An input port, used to connect to an external input power source and to obtain an input voltage; An output port, used to be connected to a laser emitter via a power bus, and used to provide an operating voltage to the laser emitter; wherein a bus capacitor is connected between the power bus and a preset voltage terminal; A charging circuit is connected between the input port and the output port; the charging circuit includes a first switching circuit and an energy storage inductor; the first switching circuit turns on the input port and the output port in response to a first level of a first drive signal; the energy storage inductor is used to form a resonant circuit with the bus capacitor to charge the bus capacitor after the laser emitter is triggered and the first switching circuit is turned on until the voltage on the power bus reaches the operating voltage of the laser emitter.

2. The boost soft charging circuit for driving laser emission according to claim 1, characterized in that: The first switch circuit is also used to disconnect the input port and the output port in response to the second level of the first drive signal when the voltage on the bus capacitor reaches the operating voltage of the laser transmitter, so that the energy storage inductor stops charging the bus capacitor.

3. The boost soft charging circuit for driving laser emission according to claim 2, characterized in that: When the voltage on the bus capacitor reaches the input voltage of the input port, the first driving signal will be switched from the first level to the second level.

4. The boost soft charging circuit for driving laser emission according to claim 1, characterized in that: The first switching circuit includes a first switching tube; the control end of the first switching tube is used to obtain the first driving signal, and the first end of the first switching tube is connected to the input end of the charging circuit to obtain the input voltage; the first end of the energy storage inductor is connected to the second end of the first switching tube, and the second end of the energy storage inductor is connected to the output end of the charging circuit.

5. The boost soft charging circuit for driving laser emission according to claim 4, characterized in that: The charging circuit also includes a first diode; a first end of the first diode is connected to a second end of the energy storage inductor, and a second end of the first diode is connected to an output end of the charging circuit.

6. The boost soft charging circuit for driving laser emission according to claim 4, characterized in that: Also includes a charging return circuit; The charging reflux circuit is connected between the input port and the preset voltage terminal; the charging reflux circuit is used to form a loop with the input port and the preset voltage terminal after the energy storage inductor stops charging the bus capacitor, so that the current of the energy storage inductor flows back to the input port until the current on the energy storage inductor is zero.

7. The boost soft charging circuit for driving laser emission according to claim 6, characterized in that: The charging reflux circuit includes a second switch tube, a third switch tube and a second diode; The control end of the second switch tube is used to obtain a second driving signal, the first end of the second switch tube is connected to the second end of the energy storage inductor, and the second end of the second switch tube is connected to the input port; the control end of the third switch tube is used to obtain a third driving signal, the first end of the third switch tube is connected to the first end of the energy storage inductor, and the second end of the third switch tube is connected to the preset voltage end; The second diode is used to block the reverse current between the input port and the energy storage inductor when the current on the energy storage inductor is zero; the second diode is connected between the first end of the second switch tube and the second end of the energy storage inductor.

8. The boost soft charging circuit for driving laser emission according to claim 1, characterized in that: The inductance parameter of the energy storage inductor satisfies that the time during which the current of the energy storage inductor flows into the bus capacitor exceeds one quarter of the resonance period.

9. A laser radar, characterized in that: include: A boost soft charging circuit, a power bus and a laser emission circuit for driving laser emission as claimed in any one of claims 1 to 8; a bus capacitor and a parasitic inductor are connected between the power bus and the preset voltage terminal; The laser emission circuit includes a laser emitter and a trigger circuit; the laser emitter emits laser in response to a trigger signal sent by the trigger circuit; wherein, when the laser emitter emits laser, a resonant discharge loop formed by the bus capacitor and the parasitic inductance provides a laser driving current; The boost soft charging circuit is used to charge the bus capacitor through a resonant charging loop composed of an energy storage inductor and a bus capacitor after the laser transmitter emits laser, until the voltage on the power bus reaches the operating voltage of the laser transmitter.

10. A method for charging a laser radar, used for the laser radar as claimed in claim 9; characterized in that: The charging method comprises: monitoring the status of the laser transmitter; After determining that the laser emitter emits laser, the boost soft charging circuit for driving laser emission is controlled to charge the bus capacitor until the voltage on the bus capacitor reaches the operating voltage of the laser emitter.

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