WO2021051466A1

WO2021051466A1 - Laser emission circuit and lidar

Info

Publication number: WO2021051466A1
Application number: PCT/CN2019/111738
Authority: WO
Inventors: 陈俊麟; 芮文彬
Original assignee: 深圳市速腾聚创科技有限公司
Priority date: 2019-10-17
Filing date: 2019-10-17
Publication date: 2021-03-25
Also published as: CN112805586B; CN117169857A; CN112805586A

Abstract

A laser emission circuit and a LIDAR, relating to the field of LIDAR. A laser diode (LD) is switched from originally being connected to a drain electrode of an energy release switch element (Q2) to being connected to a second terminal of an energy storage capacitor (C2), and the second terminal of the energy storage capacitor (C2) is grounded by means of a cathode of the laser diode (LD). When the second terminal of the energy storage capacitor (C2) is caused to float by means of the laser diode (LD), the second terminal of the energy storage capacitor (C2) is no longer directly grounded. For such a laser emission circuit during an energy transfer stage, parasitic capacitance of the energy release switch element (Q2) does not cause the laser diode (LD) to emit light early due to an energy transfer charging process, thus preventing the laser diode (LD) to emit light at unexpected times, solving the problem of laser light leakage.

Description

Laser emission circuit and lidar

Technical field

This application relates to the field of laser circuits, in particular to a laser emitting circuit and a laser radar.

Background technique

In lidar, the laser emitting circuit is used to emit laser light. The working process of the laser emitting circuit is generally divided into three stages: charging stage, energy transfer stage and energy discharging stage. The charging stage includes charging an energy storage element. Storing electric energy in the energy storage element, the energy transfer phase includes transferring the stored electric energy on the energy storage element to the energy transfer element after the charging phase is completed, and the energy discharging phase includes transferring the energy after the transfer of electric energy is completed. The electric energy stored on the energy transfer element is released to drive the laser diode to emit laser light. At present, with the development of lidar, it is necessary for lidar to complete the charging stage in a shorter time. However, the inventor found that in the process of reducing the charging time, the original laser emitting circuit will emit laser in advance during the conversion stage. This causes the phenomenon of "laser light leakage", that is, the laser emitting circuit emits light at an unexpected time, which will affect the measurement performance of the lidar.

Summary of the invention

The laser emitting circuit and the lidar provided in the embodiments of the present application can solve the problem of laser light leakage caused by the laser emitting circuit emitting laser in the energy conversion stage in the related art. The technical solution is as follows:

In the first aspect, an embodiment of the present application provides a laser emitting circuit, including:

An energy charging circuit, connected to the energy transfer circuit, for storing electric energy;

The energy transfer circuit is connected to the energy charge circuit and the energy release circuit, and is used to transfer the electric energy stored in the energy charge circuit to the energy transfer circuit; the energy transfer circuit includes an energy storage capacitor and a floating diode , The first end of the energy storage capacitor is connected to the charging circuit, and the first end of the energy storage capacitor is connected through the first end of the energy release switch element; the second end of the energy storage capacitor Connected to the anode of the floating diode, the second end of the energy storage capacitor is connected to the discharge circuit, and the cathode of the floating diode is grounded;

The energy release circuit is connected to the energy conversion circuit, and is used to drive the laser diode to emit light with the electric energy stored in the energy conversion circuit; the energy release circuit includes an energy release switch element and the laser diode. The first end of the energy-releasing switch element is connected to the first end of the energy storage capacitor, the second end of the energy-releasing switch element is grounded, and the second end of the energy-releasing switch element is connected to the anode of the laser diode , The cathode of the laser diode is connected to the second end of the capacitor.

In the second aspect, an embodiment of the present application provides a laser radar, including the above-mentioned laser emitting circuit.

The beneficial effects brought by the technical solutions provided by some embodiments of the present application include at least:

The laser diode is changed from being connected to the drain of the energy-releasing switch element to being connected to the second end of the energy storage capacitor, and the second end of the energy storage capacitor is grounded through the cathode of the laser diode, and the second end of the energy storage capacitor passes through The laser diode is suspended, that is, the second end of the energy storage capacitor is no longer directly grounded. In this way, the parasitic capacitance of the energy-releasing switch element of the laser emitting circuit of the present application will not cause the laser diode to advance due to the energy conversion charging process. It emits light, so as to prevent the laser diode from emitting light at an unexpected time and solve the problem of laser light leakage.

Description of the drawings

In order to more clearly describe the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

FIG. 1 is a schematic structural diagram of a related technology laser emitting circuit provided by an embodiment of the present application;

Fig. 2 is a block diagram of a laser emitting circuit provided by an embodiment of the present application;

FIG. 3 is a schematic diagram of the structure of a laser transmission circuit provided by an embodiment of the present application;

FIG. 4 is another schematic diagram of the structure of the laser transmission circuit provided by the embodiment of the present application.

detailed description

In order to make the purpose, technical solutions, and advantages of the present application clearer, the following will further describe the embodiments of the present application in detail with reference to the accompanying drawings.

Figure 1 shows a schematic diagram of the structure of the laser emitting circuit in the related art. The working process of the laser emitting circuit is divided into three stages: charging stage, energy transfer stage and energy discharging stage. The three stages will be described in detail below.

Charging stage: the gate of the switching tube Q1 is connected to the pulse generator TX_CHG, the pulse generator TX_CHG sends rectangular pulses, and controls the on and off of the switching tube Q1; the pulse generator TX_EN sends rectangular pulses to control the on and off of the switching tube Q2 disconnect. When the switching tube Q1 is in the on state and the switching tube Q2 is in the off state, the laser emitting circuit is in the charging stage. The current generated by the power supply VCC forms a loop through the inductor L1 and the switch Q1 to charge the inductor L1. Assuming that the on-time of the switch Q1 is △t (△t is also called the charging time), the current increment in the inductor L1 follows the formula: △I=(VCC×△t)/L1 (Formula 1).

Among them, VCC in formula 1 represents the voltage value of the power supply VCC, and L1 represents the inductance value of the inductor L1.

The charged energy obeys the formula

Substitute formula 1 into formula 2 to get

According to formula 3, it can be seen that the charging energy W _L is inversely proportional to the inductance value L1, and is proportional to the square of the on-time Δt of the switch Q1. In the case of keeping the charging energy W _L unchanged, if the on-time of the switch Q1 is to be reduced, the inductance value of the inductor L1 needs to be reduced.

It can be seen from formula 1 and formula 2 that the pulse generator TX_CHG can control the width of the rectangular pulse to control the on-time of the switch tube Q1, that is, control the charging time of the inductor L1, thereby changing the size of the charging energy and adjusting the laser emission power .

Energy transfer stage: When the switch tube Q1 is in the off state and the switch tube Q2 is also in the off state, the laser emitting circuit is in the energy transfer stage. Since the current of the inductor L1 cannot change suddenly, charging energy is stored in the inductor L1, and the inductor L1 charges the energy storage capacitor C2 through the boost rectifier diode D1, so that the charging energy stored in the inductor L1 is transferred to the energy storage capacitor C2.

Although the switching tube Q1 and the switching tube Q2 are in an off state, there is a parasitic capacitance between the drain and source of the two switching tubes. Let the parasitic capacitance between the drain and the source of the switching tube Q1 be C _Q1-DS , The parasitic capacitance between the drain and source of the switch Q2 is C _Q2-DS .

Then the current increment △I of the inductor L1 will be shunted through the following three branches:

Loop 1: The current _{forms a loop from the inductor L1 to the ground GND via the parasitic capacitance C Q1-DS} , and the current on this loop is defined as I _CQ1 .

Loop 2: The current forms a loop from the inductor L1 through the boost rectifier diode D1 and the energy storage capacitor C2 to the ground GND. _{The current on this loop is defined as I C2.}

Loop 3: The current flows from L1 to the ground (GND) via the boost rectifier diode D1, laser diode LD, and C _Q2-DS . The _{current is defined as I CQ2.}

Only the loop 2 of the above three loops is the main charging loop, which realizes the energy storage effect on the energy storage capacitor C2. Loop 1 and loop 3 are both caused by parasitic capacitance.

Considering that the forward voltage drop of the boost rectifier diode D1 and the laser diode LD is relatively small, and the influence on each circuit is small, in order to simplify the calculation, ignore the influence of the boost rectifier diode D1 and the laser diode LD on the voltage drop of the circuit, and get △ I = I _C2 + I _CQ1 + I _CQ2 (Equation 4).

Suppose C _Q1-DS = C _Q2-DS = C ₂ /N, N is a number greater than 0, C _Q1-DS represents the capacitance value of the parasitic capacitance of the switch Q1, and C _Q2-DS represents the parasitic capacitance of the switch Q2 The capacitance value, C ₂ represents the capacitance value of the energy storage capacitor C2. The current value flowing through each loop is:

According to loop 3, it can be seen that I _CQ2 is equal to the current I _{LD of the} laser diode LD, that is, I _CQ2 =I _LD (Equation 8). Set the current threshold of the laser diode LD to emit light as I _LD-TH , if I _{CQ2 is} greater than the current threshold greater than I _LD-TH , the laser diode LD will emit laser light during the transition phase, causing light leakage, that is, the laser emitting circuit is in unexpected time Luminescence affects the measurement performance of lidar.

For example: in order to meet the comprehensive performance of lidar, such as: improving the system frequency point, realizing dual emission and multiple emission functions, it is required to reduce the charging time △t.

On the premise of keeping the energy W _{L of the} inductor L1 and the voltage value of the power supply VCC unchanged, it can be seen from Equation 3 that the inductance value of the inductor L1 in the charging circuit needs to be reduced accordingly. Then according to formula 1, it can be seen that if the inductance value of the inductor L1 decreases, the charging current ΔI generated by the inductor L1 will increase accordingly. Finally, according to formula 7 and formula 8, when the charging current △I increases, the current flowing through the laser diode LD during the energy conversion process will also increase, so that the current flowing through the laser diode LD may meet I _CQ2 ＝I _LD ≥I _LD-TH . At this time, the laser diode LD will emit light at an unexpected time, causing the phenomenon of "laser light leakage".

Discharging stage: When the switching tube Q1 is in the off state and the switching tube Q2 is in the on state, the laser emitting circuit is in the discharging stage. The energy stored on the energy storage capacitor C2 will form a loop through the laser diode LD and the switch Q2 to the ground GND, and drive the laser diode LD to emit laser light, so that the laser diode LD emits laser light at the expected time.

In order to solve the above technical problems, an embodiment of the present application provides a laser emitting circuit. As shown in FIG. 2, the laser emitting circuit of the embodiment of the present application includes: a charging circuit 201, a conversion circuit 202, and a discharging circuit 203. The charging circuit 201 is connected to the energy conversion circuit 202, and the energy conversion circuit 202 is connected to the energy discharging circuit 203. The charging circuit 201 is used to store electrical energy, the conversion circuit 202 is used to transfer the stored electrical energy in the charging circuit 201 to the conversion circuit, and the discharge circuit 203 is used to drive the laser diode with the electrical energy stored in the conversion circuit 202 Glow.

Referring to FIG. 3, which is a schematic diagram of the structure of the energy transfer circuit 202 and the energy release circuit 203 according to the embodiment of the application, the energy transfer circuit 202 includes an energy storage capacitor C2 and a floating diode D2. The energy release circuit 203 includes an energy storage capacitor C2, an energy release switch element, and a laser diode LD. The energy release switch element includes two switch terminals and a control terminal (not shown in Figure 2). The control terminal inputs a control signal (such as pulse Signal) to control the closing or opening of the two switch terminals to realize the on or off state of the discharging switch element. Among them, the energy-releasing switching element can be GaN (Gallium nitride), MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor, metal oxide semiconductor field effect transistor) or IGBT (Insulated Gate Bipolar Transistor, insulated gate bipolar transistor). Type transistor).

The connection relationship between the components in the energy transfer circuit 202 and the energy release circuit 203 is: the first end of the energy storage capacitor C2 is connected to the charging circuit 201, and the first end of the energy storage capacitor C2 is connected to the first end of the energy release switch element Connected; the second end of the energy storage capacitor C2 is connected to the anode of the floating diode D2, and the second end of the energy storage capacitor C2 is connected to the cathode (K) of the laser diode LD; the cathode of the floating diode D2 is grounded , The anode (A) of the laser diode LD is grounded, and the anode of the laser diode LD is connected to the second end of the energy release switch element. Among them, the first end and the second end of the energy-releasing switch element in this embodiment refer to the two switch ends of the energy-releasing switch element.

The working process of the laser emitting circuit in Figure 3 includes:

In the charging phase, the energy storage element in the charging circuit 201 stores the electric energy supplied by the power supply, and after the charging action is completed, the energy conversion phase is performed.

In the energy transfer stage, the discharging switch element is in an off state, that is, both ends of the discharging switch element are open. The charging circuit 201 uses the stored electric energy to charge the energy conversion circuit 202, specifically by transferring the electric energy to the energy storage capacitor C2 in the energy conversion circuit 202. Although the discharging switch element is in the off state, there is a certain parasitic capacitance in the discharging switch element. In fact, the current from the charging circuit 201 will form two loops, one loop is through the energy storage capacitor C2 and the floating diode D2 To the ground GND, and during the charging process of the energy storage capacitor C2, the laser emitting tube LD is in the reverse bias cut-off state, and the energy transfer action is completed. The other loop is the loop formed by the parasitic capacitance of the energy-releasing switch element to the ground GND. It can be seen that the two loops no longer pass through the laser diode LD, so the laser diode will not have "laser light leakage" during the energy conversion stage, that is, It will not emit light at unexpected times, which solves the problem of "laser light leakage". After the energy transfer of the energy storage capacitor C2 is completed, the energy release stage is carried out.

In the discharging phase, the discharging switch is in the on state, and the electric energy stored on the energy storage capacitor passes through the two ends of the discharging switch element and the laser diode LD back to the second end of the energy storage capacitor to form a discharging circuit to drive the laser diode LD Glow.

In one embodiment, the energy conversion circuit further includes a boost rectifier diode, the anode of the boost rectifier diode is connected to the charging circuit 201, the cathode of the boost rectifier diode is connected to the first end of the energy storage capacitor C2, and the boost rectifier diode It has a one-way conduction function. Only the charging circuit 201 is allowed to charge the energy storage capacitor C2 during the energy transfer phase to prevent the energy storage capacitor C2 from causing the return of the energy in the energy storage capacitor C2 when the potential is higher than that of the charging circuit 201 . Wherein, it can be understood that the boost rectifier diode may be a Schottky diode.

In one or more embodiments, the energy-releasing switching element is a transistor, the collector of the transistor is connected to the first end of the energy storage capacitor C2, the emitter of the transistor is grounded, and the emitter of the transistor is connected to the anode of the laser diode LD. The base of is connected to the output terminal of the first pulse generator. The first pulse generator can send out pulses, such as rectangular pulses. When the rectangular pulse is at a high level, it controls the conduction between the collector and emitter of the transistor; when the rectangular pulse is at a low level, it controls the disconnection between the collector and the emitter of the transistor. The duration of the high level of the rectangular pulse is the on-time of the transistor.

In one or more embodiments, the energy-releasing switch element is a transistor, the emitter of the transistor is connected to the first end of the energy storage capacitor C2, the collector of the transistor is grounded, and the collector of the transistor is connected to the anode of the laser diode LD. The base of is connected to the output terminal of the first pulse generator. The first pulse generator can send out pulses, such as rectangular pulses. When the rectangular pulse is at a high level, it controls the disconnection between the collector and emitter of the transistor; when the rectangular pulse is at a low level, it controls the conduction between the collector and the emitter of the transistor. The duration of the low level of the rectangular pulse is the on-time of the transistor.

In one or more embodiments, the energy-releasing switch element is a gallium nitride (GaN) switch tube, the gallium nitride switch tube is a MOS (Metal Oxide Semiconductor, metal oxide semiconductor) tube, and the drain of the gallium nitride switch tube Connected to the first end of the energy storage capacitor C2, the source of the gallium nitride switch is grounded, the source of the gallium nitride switch is connected to the anode of the laser diode, and the gate of the gallium nitride switch is connected to the first pulse generator The output terminal is connected. The first pulse generator can send out pulses, such as rectangular pulses, to control the conduction or disconnection between the collector and emitter of the gallium nitride switch tube. The duration of the rectangular pulse is the conduction time of the gallium nitride switch tube .

In one or more embodiments, the charging circuit includes a power supply, a decoupling capacitor, an inductor, and a charging switch element. The power source is a DC power source, the positive pole of the power source is connected to the first end of the inductor, the second end of the inductor is grounded through the charging switch element, and the second end of the inductor is connected to the first end of the energy storage capacitor C2. Decoupling capacitors are used to eliminate parasitic coupling between circuits. When the charging switch element is in the on state, the power supply charges the inductor. After the charging is completed, the inductor stores electric energy. Among them, the charging switching element can be a gallium nitride switch tube, a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor, metal oxide semiconductor field effect transistor) or an IGBT (Insulated Gate Bipolar Transistor, insulated gate bipolar transistor)

Further, the charging switch element is a transistor, the collector of the transistor is connected to the first end of the energy storage capacitor C2, the emitter of the transistor is grounded, and the base of the transistor generates a second pulse. The output terminal of the device is connected; the second pulse generator outputs a high level to control the crystal to be in the on state, and the output low level to control the transistor to be in the off state; or

The charging switch element is a transistor, the emitter of the transistor is connected to the first end of the energy storage capacitor C2, the collector of the transistor is grounded, and the base of the transistor is connected to the output of the second pulse generator. Terminal is connected, the second pulse generator outputs a high level to control the crystal to be in the off state, and outputs a low level to control the transistor to be in the on state; or

The charging switch element is a gallium nitride switch tube, the drain of the gallium nitride switch tube is connected to the first end of the energy storage capacitor C2, the source of the gallium nitride switch tube is grounded, and the The gate of the gallium nitride switch tube is connected to the output terminal of the second pulse generator. The second pulse generator is used to control the on-time of the charging switch element.

In one or more embodiments, the discharging circuit 203 further includes a dynamic compensation capacitor connected across the two ends of the discharging switch element, and the dynamic compensation capacitor is connected across the two ends of the discharging switch element. On the switch side. The dynamic compensation capacitor can suppress the current resonance caused by the parasitic parameters of the discharge circuit of the energy storage capacitor C2, and supplement the dynamic impedance when the energy release switch element is turned on.

In one or more embodiments, the capacitance value of the dynamic compensation capacitor is smaller than the capacitance value of the energy storage capacitor.

In one or more embodiments, the energy storage capacitor C2 may be composed of multiple capacitors in parallel to reduce the ESR (Equivalent Series Resistance) of the energy storage capacitor C2. It is understandable that the capacitance values of the multiple capacitors may be equal or unequal. Preferably, the capacitance values of the multiple capacitors connected in parallel are the same, the ESR consistency of the capacitors with the same capacitance value in parallel is better, and the discharge of each parallel capacitor is more equal, which can better improve the efficiency of the energy storage capacitor.

It is understandable that the ground connection of the various components in Figure 3 (for example: floating diode D2, laser diode LD, and energy release switch element) can be changed to connect to the negative pole of the power supply, which can also realize the laser in Figure 3 The same function as the transmitting circuit. Wherein, it can be understood that the negative pole of the power supply can be grounded.

Referring to FIG. 4, a specific structural diagram of a laser emitting circuit provided by an embodiment of this application. In this embodiment of the application, the charging circuit 201 includes a power supply VCC, an inductor L1, a decoupling capacitor C1, and a MOS tube Q1. Q1 is a charging switch element. The energy conversion circuit 202 includes a boost rectifier diode D1, an energy storage capacitor C2, and a floating diode D2. The energy release circuit 203 includes an energy storage capacitor C2, a MOS tube Q2, a dynamic compensation capacitor C3, and a laser diode LD, and the MOS tube Q2 serves as an energy release switch element.

The connection relationship of each element in Figure 4 is: the negative pole of the power supply VCC is grounded, the positive pole of the power supply VCC is grounded through the decoupling capacitor C1, and the positive pole of the power supply VCC is also connected to the inductor L1 and the drain (D) of the MOS transistor Q1, MOS The drain of the tube Q1 is connected to the anode of the boost rectifier diode D1 at the same time; the source (S) of the MOS tube Q1 is grounded, and the gate (G) of the MOS tube Q1 is connected to the output terminal of the pulse generator TX_CHG.

The cathode of the boost rectifier diode D1 is connected to the first end of the energy storage capacitor C2, and the cathode of the boost rectifier diode D2 is also connected to the drain (D) of the MOS transistor Q2. The second end of the energy storage capacitor C2 is connected to the anode of the floating diode D2, and the cathode of the floating diode D2 is grounded. The second end of the energy storage capacitor C2 is connected to the cathode (K) of the laser diode LD, the anode (A) of the laser diode LD is grounded, and the anode of the laser diode LD is connected to the source (S) of the MOS tube Q2, the MOS tube Q2 The gate (G) is connected to the output terminal of the pulse generator TX_EN. The dynamic compensation capacitor C3 is connected across the source and drain of the MOS transistor Q2.

It is understandable that the ground connection of the various components in Figure 4 (for example: decoupling capacitor C1, MOS transistor Q1, floating diode D2, laser diode LD and MOS transistor Q2) can be changed to be connected to the negative pole of the power supply, the same The same function as the laser emitting circuit in Figure 4 can also be achieved. Wherein, it can be understood that the negative pole of the power supply may be grounded.

Wherein, the capacitance value of the dynamic compensation capacitor C3 is smaller than the capacitance value of the energy storage capacitor C2, and the capacitance value range of the dynamic compensation capacitor C3 can be between 2pF-10nF, for example: the capacitance value of the dynamic compensation capacitor C3 is 100pF. The capacitance value range of the energy storage capacitor C2 may be between 2pF and 20nF. For example, the capacitance value of the energy storage capacitor C2 is 2nF. The inductance value range of the inductor L1 may be between 10 nH and 100 μH. For example, the inductance value of the inductor L1 is 330 nH. The value range of the parameter value of the above-mentioned element is only for the parameter, and the embodiment of the present application is not limited to this.

The working process of the laser emitting circuit of Fig. 4 includes:

1. The charging stage.

The pulse generator TX_CHG sends a rectangular pulse to the gate of the MOS tube Q1 to control the MOS tube Q1 to be in the on state, and at this time the MOS tube Q2 to be in the off state. The power supply VCC charges the inductor, and the decoupling capacitor C1 is connected in parallel between the positive and negative electrodes of the power supply VCC, which can prevent the parasitic oscillation caused by the circuit through the positive feedback path formed by the power supply VCC. The so-called decoupling is to prevent the current fluctuations formed in the power supply circuit from affecting the normal operation of the circuit when the currents of the front and rear circuits change. In other words, the decoupling circuit can effectively eliminate the parasitic coupling between the circuits.

2. Energy transfer stage.

After the charging is completed, the pulse generator TX_CHG stops sending rectangular pulses to the MOS transistor Q1, the MOS transistor Q1 is in the off state, and the MOS transistor Q2 is still in the off state at this time. Because the current of the inductor l 1 cannot change suddenly, the inductor L1 will continue the potential generated by ΔI to generate two currents through the boost rectifier diode D1, one of which charges the energy storage capacitor C2, and the charging current passes through the boost rectifier diode D1, the energy storage capacitor C2, the floating diode D2 and the ground form a loop, and during the charging process of the energy storage capacitor C2, the laser diode LD is in a reverse bias cut-off state. The other conversion charging current passes through the parasitic capacitance C _Q2-DS (not shown in the figure) of the MOS transistor Q2 and the dynamic compensation capacitor C3 to form another loop, and flows through the parasitic capacitance C _Q2-DS of the MOS transistor Q2 Current no longer flows through the laser diode LD.

Obviously, neither of the above two charging currents will flow through the laser diode LD, so it will not emit light at an unexpected time, which solves the problem of laser light leakage.

Among them, the improved laser emission circuit has the following characteristics: the laser diode LD is connected to the second end of the energy storage capacitor C2 from the original connection to the drain of the MOS transistor Q2, and the second end of the energy storage capacitor C2 is connected to the second end of the energy storage capacitor C2 through the laser diode LD. The connection to the ground is suspended, that is, the second end of the energy storage capacitor C2 is no longer directly grounded. Therefore, the laser emission circuit can also be called "laser leakage elimination floating emission circuit" in Chinese, and its English name is abbreviated as FCEL (float ground circuit for eliminating laser leakage, which eliminates laser leakage floating emission circuit).

3. Energy release stage.

The pulse generator TX_EN sends a rectangular pulse to the gate of the MOS tube Q2 to control the MOS tube Q2 to be in the on state, and at this time the MOS tube Q1 is in the off state. The energy stored in the energy storage capacitor C2 forms an energy release (discharge) circuit through the drain and source of the MOS transistor Q2, the laser diode LD, and the second end of the energy storage capacitor C2, and drives the laser diode LD to complete the laser emission action. In addition, the dynamic compensation capacitor C3 also forms its own discharge circuit through the drain and source of the MOS transistor Q2, which releases the stored electric energy during the energy transfer and prepares for the next cycle of laser transmission.

An embodiment of the present application also provides a laser radar, including the above-mentioned laser emission circuit.

Specifically, the above-mentioned laser emitting circuit can be applied to a laser radar. In addition to the laser emitting circuit, the laser radar can also include specific structures such as a power supply, a processing device, an optical receiving device, a rotating body, a base, a housing, and a human-computer interaction device. It is understandable that the lidar can be a single-channel lidar, including one of the above-mentioned laser emission circuits, and the lidar can also be a multi-channel lidar, including multiple channels of the above-mentioned laser emission circuit and the corresponding control system. The quantity can be determined according to actual needs.

In the above-mentioned laser radar, by changing the structure of the laser emitting circuit, the laser diode LD is connected to the second end of the energy storage capacitor C2 from the original connection to the drain of the MOS transistor Q2, and the second end of the energy storage capacitor C2 passes through the laser diode LD The cathode of the energy storage capacitor C2 is grounded, and the second end of the energy storage capacitor C2 is suspended by the laser diode LD, that is, the second end of the energy storage capacitor C2 is no longer directly connected. The charging process causes the laser diode to emit light in advance, which prevents the laser diode from emitting light at an unexpected time and solves the problem of laser light leakage.

A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing relevant hardware through a computer program. The program can be stored in a computer readable storage medium, and the program can be stored in a computer readable storage medium. During execution, it may include the procedures of the above-mentioned method embodiments. Wherein, the storage medium can be a magnetic disk, an optical disc, a read-only storage memory or a random storage memory, etc.

The above-disclosed are only preferred embodiments of this application, and of course the scope of rights of this application cannot be limited by this. Therefore, equivalent changes made in accordance with the claims of this application still fall within the scope of this application.

Claims

A laser emitting circuit, characterized in that it comprises:

An energy charging circuit, connected to the energy transfer circuit, for storing electric energy;

The conversion circuit is connected to the charging circuit and the discharging circuit, and is used to transfer the electric energy stored in the charging circuit to the conversion circuit; the conversion circuit includes an energy storage capacitor and a floating ground Diode, the first end of the energy storage capacitor is connected to the charging circuit, and the first end of the energy storage capacitor is connected to the first end of the energy release switch element; the second end of the energy storage capacitor The terminal is connected to the anode of the floating diode, the second terminal of the energy storage capacitor is connected to the discharge circuit, and the cathode of the floating diode is grounded;

The energy release circuit is connected to the energy conversion circuit and is used to drive the laser diode to emit light with the electric energy stored in the energy conversion circuit; the energy release circuit includes an energy release switch element and the laser diode, and the energy release circuit includes an energy release switch element and the laser diode. The first end of the energy-releasing switch element is connected to the first end of the energy storage capacitor, the second end of the energy-releasing switch element is grounded, and the second end of the energy-releasing switch element is connected to the anode of the laser diode , The cathode of the laser diode is connected to the second end of the capacitor.
The laser emitting circuit according to claim 1, wherein the power conversion circuit further comprises a boost rectifier diode, the anode of the boost rectifier diode is connected to the charging circuit, and the boost rectifier diode The cathode is connected to the first end of the energy storage capacitor.
The laser emitting circuit according to claim 1, wherein the energy-releasing switch element is a transistor, the collector of the transistor is connected to the first end of the energy storage capacitor, and the emitter of the transistor is grounded and The emitter of the transistor is connected to the anode of the laser diode, and the base of the transistor is connected to the output terminal of the first pulse generator; or

The energy-releasing switch element is a transistor, the emitter of the transistor is connected to the first end of the energy storage capacitor, the collector of the transistor is grounded, and the collector of the transistor is connected to the anode of the laser diode, The base of the transistor is connected to the output terminal of the first pulse generator; or

The energy release switch element is a gallium nitride switch tube, the drain of the gallium nitride switch tube is connected to the first end of the energy storage capacitor, the source of the gallium nitride switch tube is grounded and the nitrogen The source of the gallium nitride switch tube is connected with the anode of the laser diode, and the gate of the gallium nitride switch tube is connected with the output terminal of the first pulse generator.
The laser emitting circuit according to claim 1, wherein the charging circuit includes a power supply, a decoupling capacitor, an inductor, and a charging switch element;

Wherein, the negative pole of the power supply is grounded, the positive pole of the power supply is grounded through the decoupling capacitor, and the positive pole of the power supply is connected to the first end of the inductor, and the second end of the inductor is grounded through the charging switch element. And the second end of the inductor is connected to the first end of the energy storage capacitor.
The laser emitting circuit according to claim 4, wherein the charging switch element is a transistor, the collector of the transistor is connected to the first end of the energy storage capacitor, and the emitter of the transistor is grounded, The base of the transistor is connected to the output terminal of the second pulse generator; or

The charging switch element is a transistor, the emitter of the transistor is connected to the first terminal of the energy storage capacitor, the collector of the transistor is grounded, and the base of the transistor is connected to the output terminal of the second pulse generator. Connected; or

The charging switch element is a gallium nitride switch tube, the drain of the gallium nitride switch tube is connected to the first end of the energy storage capacitor, the source of the gallium nitride switch tube is grounded, and the nitrogen The grid of the gallium sulfide switch tube is connected with the output terminal of the second pulse generator.
The laser emitting circuit of claim 1, wherein the energy-releasing circuit further comprises a dynamic compensation capacitor, and the dynamic compensation capacitor is connected across the two ends of the energy-releasing switch element.
7. The laser emitting circuit of claim 6, wherein the capacitance value of the dynamic compensation capacitor is smaller than the capacitance value of the energy storage capacitor.
The laser emitting circuit according to claim 1, wherein the energy storage capacitor is composed of a plurality of capacitors in parallel.
The laser emitting circuit according to claim 1, wherein the boost rectifier diode and the floating diode are Schottky diodes.
A laser radar, characterized by comprising: the laser emitting circuit according to any one of claims 1 to 9.