Laser emission circuit and control method thereof, and laser radar

Abstract

The invention discloses a laser emission circuit and a control method thereof, and a laser radar. The laser emission circuit comprises a power supply module and a laser emission module. The power supply module comprises an energy acquisition unit, a boost control unit and an energy storage unit, and the energy acquisition unit comprises a plurality of inductors connected in parallel; the laser emission module comprises an emission unit and an emission control unit; the boost control unit is used for controlling the energy acquisition unit to acquire energy of an external power supply or controlling the energy acquisition unit to transmit the energy to the energy storage unit; and the emission control unit is used for controlling the emission unit to emit a laser pulse by using the energy stored by the energy storage unit after the energy storage of the energy storage unit is completed. By means of the scheme, the inductance energy storage and capacitor charging efficiency of the power supply module in the laser emission circuit can be improved, and the circuit integration degree and reliability are high.

Description

Technical Field

[0001] The present invention relates to the field of circuit technology, and in particular to a laser emission circuit and a control method thereof, and a laser radar. Background Art

[0002] In order to resist interference, laser radar needs to emit multiple laser pulses in a short period of time, encode the multiple transmitted pulses during transmission (that is, set the pulse amplitude and pulse interval), and filter out the echo signal of the transmitted pulse emitted by itself after being reflected by the object from the multiple pulses of the received signal according to the coding information of the transmitted pulse, so as to achieve the purpose of anti-interference.

[0003] The energy of resonant laser emission comes from the charge stored in the resonant capacitor after the boost circuit. In the traditional BOOST circuit, due to the long time of inductor energy storage and capacitor charging, the time required for the laser to complete a light emission is also relatively long. Since the time window that the laser radar can provide for ranging is limited, it is difficult to provide enough time to complete the emission of multiple pulses, which is not conducive to improving the anti-interference performance of the laser radar. Summary of the invention

[0004] The present invention provides a laser emitting circuit and a control method thereof, and a laser radar, so as to improve the inductive energy storage and capacitive charging efficiency of a power supply module in the laser emitting circuit, and the circuit has high integration and reliability.

[0005] To this end, the present invention provides the following technical solutions:

[0006] In one aspect, the present invention provides a laser emission circuit, the laser emission circuit comprising: a power supply module and a laser emission module; the power supply module comprises: an energy acquisition unit, a boost control unit, and an energy storage unit, the energy acquisition unit comprises a plurality of parallel inductors; the laser emission module comprises an emission unit and an emission control unit;

[0007] The boost control unit is used to control the energy acquisition unit to acquire energy from an external power source, or to control the energy acquisition unit to transfer the energy to the energy storage unit;

[0008] The emission control unit is used to control the emission unit to emit laser pulses using the energy stored in the energy storage unit after the energy storage unit completes energy storage.

[0009] Optionally, the inductance values ​​of the multiple inductors are the same.

[0010] Optionally, the boost control unit includes: a first switch subunit and a first drive subunit;

[0011] The first driving subunit is used to drive the first switch subunit to close or open;

[0012] The energy acquisition unit acquires energy from an external power source after the first switch subunit is closed; and transmits the energy to the energy storage unit after the first switch subunit is opened.

[0013] Optionally, the transmitting control unit includes: a second switch subunit and a second driving subunit;

[0014] The second driving subunit is used to drive the second switch subunit to close or open;

[0015] The emission unit emits laser pulses after the second switch subunit is closed.

[0016] Optionally, the first switch subunit and the second switch subunit are transistors.

[0017] Optionally, the laser pulse is a single pulse or multiple pulses.

[0018] On the other hand, the present invention also provides a laser emission circuit control method, the laser emission circuit comprises: a power supply module and a laser emission module; the power supply module comprises: an energy acquisition unit, a boost control unit, and an energy storage unit, the energy acquisition unit comprises a plurality of parallel inductors, the boost control unit is used to control the energy acquisition unit to acquire energy from an external power source, or control the energy acquisition unit to transfer the energy to the energy storage unit; the laser emission module comprises an emission unit and an emission control unit, the emission control unit is used to control the emission unit to emit laser pulses using the energy stored in the energy storage unit after the energy storage unit completes energy storage;

[0019] The method comprises:

[0020] Inductor charging stage: using the external power supply to charge the multiple parallel-connected inductors so that the inductors obtain energy;

[0021] Inductive discharge stage: transferring the energy to the energy storage unit;

[0022] Laser emission stage: after the energy storage unit completes energy storage, laser pulses are emitted using the energy stored in the energy storage unit.

[0023] Optionally, the inductive charging stage further includes: adjusting the charging time of the inductive charging stage according to the energy required for emitting the laser pulse.

[0024] Optionally, the laser emission stage includes: after the energy storage unit completes energy storage, electrically connecting the energy storage unit to a laser emission module, so that the laser emission module emits laser pulses.

[0025] Optionally, the laser emission stage further includes: after the laser pulse emission is completed, disconnecting the energy storage unit from the laser emission module.

[0026] Optionally, the method further includes: repeatedly executing the inductive charging stage to the laser emitting stage to emit the laser pulses multiple times.

[0027] Optionally, the charging duration of the inductive charging stage corresponding to each emission of the laser pulse remains the same or different.

[0028] Optionally, the method further comprises: after the laser emission phase is completed, performing the next inductive discharge phase.

[0029] On the other hand, the present invention further provides a laser radar, the laser radar comprising the laser transmitting circuit and the laser receiving circuit as described above;

[0030] The laser emission circuit is used to emit laser pulses;

[0031] The laser receiving circuit is used to receive the laser pulse.

[0032] The laser emission circuit and control method thereof, and laser radar provided by the present invention utilize multiple parallel inductors to obtain energy from an external power source, transmit the energy to an energy storage unit, and utilize the energy stored in the energy storage unit to emit laser pulses. Multiple parallel inductors share a set of drive circuits, and the total inductance value can be reduced by using multiple inductors in association, thereby shortening the energy storage time of the inductors, improving the efficiency of inductor energy storage and capacitor charging, and ensuring that the total energy storage meets the system requirements. Since multiple parallel inductors share a set of drive circuits, there is no need to add other drive circuits, thereby avoiding increasing hardware costs; and compared with the inductors for energy storage in the existing laser emission circuit, each parallel inductor in the present invention can use a smaller inductance value, so the package can be made smaller, the volume of the inductor can be smaller, and it is more conducive to circuit system integration, thereby improving the integration of the circuit system. In addition, by utilizing the solution of the present invention, it is possible to avoid adding too many discrete devices, improve the reliability of the system, and reduce the probability of light pulse loss due to device failure or poor welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0034] Figure 1 It is a schematic diagram of the structure of a laser emission circuit;

[0035] Figure 2 yes Figure 1 The simulation schematic diagram of the relevant signals in the single pulse laser emission circuit shown;

[0036] Figure 3 It is a structural schematic diagram of an existing multi-pulse laser emission circuit;

[0037] Figure 4 yes Figure 3 A simulation schematic diagram of related signals in the multi-pulse laser emission circuit shown;

[0038] Figure 5 is a principle block diagram of a laser emission circuit provided by an embodiment of the present invention;

[0039] Figure 6 is a structural schematic diagram of a laser emission circuit provided by an embodiment of the present invention;

[0040] Figure 7 yes Figure 6 A simulation schematic diagram of related signals in the laser emission circuit shown;

[0041] Figure 8 It is a timing diagram of emitting a single pulse laser signal using the laser emitting circuit provided by an embodiment of the present invention;

[0042] Fig. 9 It is a timing diagram of emitting a double-pulse laser signal using the laser emitting circuit provided by an embodiment of the present invention;

[0043] Fig.10 It is a timing diagram of emitting three-pulse laser signals using the laser emitting circuit provided in an embodiment of the present invention;

[0044] Fig.11 is a flow chart of a laser emission circuit control method provided by an embodiment of the present invention;

[0045] Fig.12 It is a structural schematic diagram of a laser radar provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0046] In order to make the above-mentioned objects, features and beneficial effects of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0047] The following first briefly describes a laser emission circuit.

[0048] The laser emission circuit is usually a combination of a BOOST circuit and a resonant laser emission circuit, such as Figure 1As shown, it is a structural schematic diagram of an existing laser emission circuit. Figure 2 Figure 3 is a simulation diagram of the relevant signals.

[0049] Combine the following Figure 1 and Figure 2 Explain the working principle of the laser emission circuit.

[0050] Reference Figure 1 The laser emission circuit includes a BOOST circuit 11 and a resonant laser emission circuit 12. The BOOST circuit 11 includes a switch tube Q1, an inductor L1, a capacitor C1, and voltage-stabilizing diodes D11 and D22, and the resonant laser emission circuit 12 includes a laser LA and a switch tube QA.

[0051] Combination Figure 2 The signals shown in the figure, among which U1 represents the driving signal of the switch tube Q1, U LA Represents the control signal of the switch tube QA; V C1 Represents the voltage on capacitor C1; Iout represents the current flowing through the laser LA.

[0052] After U1 jumps from a low level to a high level, the switch tube Q1 is closed, and energy is stored in the inductor L1 through the external power supply; after U1 jumps from a high level to a low level, the switch tube Q1 is disconnected, the inductor L1 charges the capacitor C1, and the energy is transferred from the inductor L1 to the capacitor C1.

[0053] After the capacitor C1 is charged, control U LA It becomes a high level, that is, the switch tube QA is closed, the capacitor C1 is discharged, and the laser LA generates a pulse current Iout.

[0054] Figure 1 The laser emission circuit shown can realize the single-pulse laser emission function, and the time to complete one laser pulse emission is: the energy storage time of the inductor L1 + the charging time of the capacitor C1 + the light-emitting time of the laser LA, which is usually 418ns. Since both the inductor energy storage and the capacitor charging take a long time, the circuit cannot complete the emission of multiple pulses in a short time. For example, in the ranging process, three laser pulses must be emitted within 300ns, and the above circuit needs at least 418×2ns to complete the emission of three laser pulses, which obviously cannot meet the requirements.

[0055] In order to meet the above requirement of achieving continuous multiple pulse transmission in a short time, a solution provided by the prior art is to adopt a method of expanding multiple BOOST circuits, and the multiple BOOST circuits charge the resonant capacitor in turn. However, since this solution needs to expand multiple BOOST circuits, the circuit integration is low and the cost is high.

[0056] like Figure 3 The figure shows a schematic diagram of the structure of an existing multi-pulse laser emission circuit.

[0057] The multi-pulse laser emission circuit adopts three BOOST circuits. The three BOOST circuits use independent switch tubes Q1, Q2, Q3 to control the energy storage of their respective inductors L1, L2, L3 through their respective drive signals U1, U2, U3. The three BOOST circuits share one energy storage capacitor C1. Figure 3 Among them, D11, D21, D31, and D22 are voltage-stabilizing diodes.

[0058] Figure 3 The simulation schematic diagram of the related signals in the multi-pulse laser emission circuit is shown in Figure 4 shown.

[0059] Also refer to Figure 3 and Figure 4 At t11, U1 changes from low level to high level, the switch tube Q1 is closed, and the inductor L1 is charged with energy through the external power supply; at t12, U1 changes from high level to low level, the switch tube Q1 is disconnected, the inductor L1 charges the capacitor C1, and the energy is transferred from the inductor L1 to the capacitor C1; at t13, after the capacitor C1 is charged, the control U LA It becomes a high level, that is, the switch tube QA in the laser emitting circuit 12 is closed, and the capacitor C1 is discharged, so that the laser LA generates a pulse current Iout; it should be noted that the switch tube QA can be closed at any time after the capacitor C1 is charged, so that the laser LA emits a laser pulse, and is not limited to being closed immediately after the capacitor C1 is charged.

[0060] At t21 before t12 when inductor L1 charges capacitor C1, U2 jumps from low level to high level, and switch Q2 closes, which means that the inductor L2 starts to store energy through the external power supply. Correspondingly, at t22 after the last discharge of capacitor C1 is completed, U2 jumps from high level to low level, and switch Q2 is disconnected, inductor L2 charges capacitor C1, and energy is transferred from inductor L2 to capacitor C1; at t23, after capacitor C1 is fully charged, U LAIt becomes a high level, the switch tube QA is closed, the capacitor C1 is discharged, and the laser LA generates a pulse current Iout; it should be noted that when the inductor L2 charges the capacitor C1, it is necessary to ensure that the capacitor C1 has completed the last discharge, that is, it is necessary to ensure that the moment when Q2 is disconnected (t22) is after the last discharge of the capacitor is completed; in addition, the switch tube QA can be closed at any time after the capacitor C1 is charged for the second time, so that the laser LA emits a laser pulse, and is not limited to being closed immediately after the capacitor C1 is charged for the second time. Therefore, the time interval between the two pulses emitted by the laser LA can be adjusted by adjusting the closing time of the switch tube QA and / or adjusting it to the charging time of the inductor L2 (that is, the time interval between t21 and t11).

[0061] Similarly, at t31, U3 jumps from low level to high level, the switch tube Q3 closes, and starts to store energy in the inductor L3 through the external power supply. Correspondingly, at t32, after the capacitor C1 is discharged, U3 jumps from high level to low level, the switch tube Q3 is disconnected, the inductor L3 charges the capacitor C1, and the energy is transferred from the inductor L3 to the capacitor C1; at t33, after the capacitor C1 is charged, U LA It becomes a high level, the switch tube QA is closed, and the capacitor C1 is discharged, so that the laser LA generates a pulse current Iout. The principle of adjusting the pulse interval is the same as above and will not be repeated here.

[0062] The advantage of this solution is that the inductors in different BOOST circuits can store energy simultaneously or successively within a certain period of time without affecting each other. Figure 3 The inductors L1, L2, and L3 in the circuit store energy in succession at a time interval of 100ns, and each inductor takes 340ns to store energy. Then, the resonant capacitor C1 is charged in succession at a time interval of 100ns. The laser LA emits light immediately after the capacitor C1 is fully charged each time. Therefore, the laser LA can emit light once after the inductor L1 fully charges the capacitor C1, and the laser LA can emit light for the second time after the inductor L2 fully charges the capacitor C1, and the laser LA can emit light for the third time after the inductor L3 fully charges the capacitor C1. The time interval between the three light emissions is 100ns, and the laser can complete three laser emissions within 300ns.

[0063] It should be noted that the 300 ns time window means that the three laser pulses are emitted within 300 ns, because the inductor L1 can be charged before the time window.

[0064] However, this solution requires the provision of multiple BOOST circuits, that is, multiple MOS tubes and multiple MOS tube drivers need to be added, which significantly increases the circuit scale, is costly and is not conducive to improving the circuit integration.

[0065] To this end, the present invention provides a laser emission circuit and a control method thereof, in which the energy acquisition unit in the power supply module that provides energy for the laser emission module is designed as a plurality of parallel inductor structures, and the plurality of parallel inductors share a set of driving circuits to reduce the total inductance value, shorten the energy storage time of the inductor, improve the inductor energy storage and capacitor charging efficiency, and ensure that the total energy storage meets the system requirements.

[0066] like Figure 5 , which is a principle block diagram of a laser emission circuit provided by an embodiment of the present invention.

[0067] The laser emission circuit includes: a power supply module 51 and a laser emission module 52. Among them:

[0068] The power supply module 51 includes: an energy acquisition unit 511 , a boost control unit 512 , and an energy storage unit 513 . The energy acquisition unit 511 includes a plurality of inductors connected in parallel.

[0069] The laser emitting module 52 includes an emitting unit 521 and an emitting control unit 522 .

[0070] In this embodiment, the boost control unit 512 is used to control the energy acquisition unit 511 to acquire energy from an external power source, or to control the energy acquisition unit 511 to transfer the energy to the energy storage unit 513 .

[0071] Correspondingly, the emission control unit 522 is used to control the emission unit 521 to emit laser pulses using the energy stored in the energy storage unit 513 after the energy storage unit 513 completes energy storage.

[0072] In a specific application, the inductance values ​​of the multiple parallel inductors in the energy acquisition unit 511 may be the same or different, and this is not limited in the embodiment of the present invention. In addition, it should be noted that the maximum total energy that can be stored by the multiple inductors needs to be greater than or equal to the energy required for the transmitting unit 521 to transmit a pulse.

[0073] In a non-limiting embodiment, the boost control unit 512 may include: a first switch subunit and a first drive subunit, wherein the first drive subunit is used to drive the first switch subunit to close or open.

[0074] Correspondingly, the energy acquisition unit 511 acquires energy from the external power source after the first switch subunit is closed; and transmits the energy to the energy storage unit 513 after the first switch subunit is opened.

[0075] In a non-limiting embodiment, the transmitting control unit 522 may include: a second switch subunit and a second driving subunit, wherein the second driving subunit is used to drive the second switch subunit to close or open.

[0076] Correspondingly, the emitting unit 521 emits laser pulses after the second switch subunit is closed.

[0077] like Figure 6 , which is a schematic diagram of the structure of a laser emission circuit provided in an embodiment of the present invention.

[0078] Also refer to Figure 5 and Figure 6 ,exist Figure 6 In the illustrated embodiment, the energy acquisition unit 511 in the power supply module 51 includes four parallel-connected inductors L11, L12, L13, and L14. Of course, the present invention does not limit the number of inductors. Figure 6 The following are just illustrative examples.

[0079] The first switch subunit in the boost control unit 512 is implemented by a transistor Q21, and the first drive subunit 5122 can be implemented by an existing drive chip.

[0080] Figure 5 The energy storage unit 513 in the embodiment can be implemented by a capacitor C31.

[0081] In addition, in the power supply module 51, a voltage stabilizing diode D41 may be provided between the inductor and the capacitor C31, and a voltage stabilizing diode D42 may be connected across the capacitor C31.

[0082] Continue to refer to Figure 5 and Figure 6 The emitting unit in the laser emitting module 52 is a laser LA, the second switch subunit in the emission control unit is implemented by a transistor QA, and the second driving subunit 5222 can be implemented by an existing driving chip.

[0083] In this embodiment, the voltage stabilizing diode D42 can prevent a large negative voltage from appearing at the output end of the power supply module 51 (ie, the output end of the capacitor C31) when the laser LA emits light, thereby damaging the laser LA or affecting the size of the next stored voltage of the capacitor C31.

[0084] The laser emitting circuit can emit a single pulse laser or a multi-pulse laser.

[0085] Combine the following Figure 6 The working process of the laser emission circuit is described in detail. In order to more intuitively show the timing relationship of the relevant signals in the circuit, you can also refer to Figure 7 , Figure 7 yes Figure 6 The simulation diagram of the relevant signals in the laser emission circuit shown in FIG. 1 is shown in FIG. 1 , wherein U11 represents the driving signal of the transistor Q21, I Lrepresents the current of four inductors, namely L11, L12, L13, and L14, U LA Represents the driving signal of transistor QA; U C31 represents the voltage on capacitor C31; Iout represents the current flowing through the laser LA.

[0086] Reference Figure 6 and Figure 7 After the driving signal U11 jumps from a low level to a high level, the transistor Q21 is closed, and the parallel inductors L11, L12, L13, and L14 simultaneously obtain energy from the external power supply; after the driving signal U11 jumps from a high level to a low level, the transistor Q21 is disconnected, and the parallel inductors L11, L12, L13, and L14 charge the capacitor C31 at the same time, and transfer the energy obtained from the external power supply to the capacitor C31.

[0087] After the capacitor C31 is charged, the control drive signal U LA It becomes a high level, that is, the switch tube QA is closed, the capacitor C31 is discharged, and the laser LA generates a pulse current Iout; it should be noted that the switch tube QA can be closed at any time after the capacitor C31 is charged to make the laser LA emit a laser pulse, and is not limited to being closed immediately after the capacitor C31 is charged. When the parallel inductors L11, L12, L13, and L14 charge the capacitor C31 for the next time, it is necessary to ensure that the capacitor C31 has completed the last discharge, that is, it is necessary to ensure that the moment when Q21 is disconnected is after the last discharge of the capacitor C31 is completed; in addition, the switch tube QA can be closed at any time after the capacitor C31 is charged for the second time to make the laser LA emit a laser pulse, and is not limited to being closed immediately after the capacitor C31 is charged for the second time. Therefore, the time interval between the two pulses emitted by the laser LA can be adjusted by adjusting the closing time of the switch tube QA and / or adjusting it to the charging time of the parallel inductors L11, L12, L13, and L14 (that is, the time interval between the two times the parallel inductors start to store energy).

[0088] The following is an analysis of the changes in the internal current and the amount of energy stored when a certain voltage is applied to the inductor.

[0089] First, the relationship between the applied voltage and internal current of the inductor is as follows:

[0090] I Δ =U / L

[0091] Among them, I Δ is the change of the current inside the inductor, U is the voltage of the external power supply connected to the inductor, and L is the inductance.

[0092] From the above formula, we can know that under the same voltage, the smaller the inductance value, the faster the current growth rate inside the inductor. In other words, the reduction of inductance value can increase the current growth rate inside the inductor, thereby shortening the energy storage time of the inductor. For example, if the inductance value is increased from the original 1uH ( Figure 1 L1 in the circuit is reduced to 220nH ( Figure 6 In the process of inductor energy storage, the internal current speed increase of the inductor will be 4.55 times of the original one.

[0093] Secondly, the formula for inductor energy storage is as follows:

[0094] W=LI 2 / 2

[0095] It can be seen from the above formula that when the same current flows through each inductor, the reduction in the inductance value of each inductor will lead to a reduction in the energy storage of each inductor, but multiple inductors connected in parallel can increase the total energy storage and meet the energy storage requirements of the energy storage unit 513.

[0096] Based on the above principle, in the solution of the present invention, multiple smaller inductors are connected in parallel, which can not only increase the speed of the current inside the inductor and shorten the energy storage time of the inductor, but also ensure that the total energy storage of the energy storage unit 513 meets the requirements. For example, Figure 6 In the illustrated embodiment, four 220nH inductors are connected in parallel to ensure that the total energy storage of the inductors meets the system requirements.

[0097] By using multiple inductors in parallel, compared with the existing Figure 1 The energy storage scheme of a single inductor shown in the figure can have the following situations:

[0098] (1) Keep the inductance value of each inductor unchanged ( Figure 6 The inductance of each inductor in Figure 1 To ensure that the total energy storage remains unchanged, the current inside each inductor needs to be reduced ( Figure 6 The current magnitude of each inductor is compared to Figure 1 The current in the inductor is reduced; since the total inductance is reduced and the current required by each inductor is reduced, the charging and discharging time is reduced accordingly;

[0099] (2) Reduce the inductance value of each inductor ( Figure 6 The inductance of each inductor in Figure 1 The inductance value shown in the figure) ensures that the total energy storage remains unchanged. There are three possible situations: the current inside each inductor can become smaller, remain unchanged, or increase ( Figure 6 The current magnitude of each inductor is compared to Figure 1 The current size in the inductor is reduced, and since the total inductance is reduced, the charging and discharging time is correspondingly reduced.

[0100] The size of the inductor energy storage will affect the energy of the subsequent laser LA to emit a single pulse laser, and the length of the inductor energy storage time will affect the time required for the subsequent laser LA to emit multiple pulse lasers. Therefore, in practical applications, the size and number of parallel inductors can be determined based on the required total energy and time, as long as the total energy storage in all inductors meets the system requirements.

[0101] In the three cases of the above-mentioned method (2), compared with the solution of keeping the current in the inductor unchanged, the current flowing through each inductor can be increased and the number of inductors connected in parallel can be reduced; or the current flowing through each inductor can be reduced and the number of inductors connected in parallel can be increased to meet the charging and discharging time requirements and the total stored energy requirements, which is not limited in this embodiment of the present invention.

[0102] It should be noted that, since the current flowing through the inductor during energy storage cannot exceed its saturation current, if the current flowing through each inductor is increased to reduce the number of parallel inductors, the selection of the inductor will be more demanding and may also cause inductor saturation, affecting the robustness of the system; while reducing the current flowing through each inductor and increasing the number of parallel inductors will increase the cost. Therefore, it is preferred to keep the current flowing through each inductor unchanged ( Figure 6 The current magnitude of each inductor is compared to Figure 1 The current size in the inductor is determined by the energy storage time requirement.

[0103] Specifically, the charging time of the capacitor C31 can be calculated according to the following formula:

[0104]

[0105] According to the above formula, when the capacitance value of the capacitor remains unchanged, reducing the inductance value can reduce the time it takes to charge the capacitor. For example, if four inductors are connected in parallel, the total inductance is calculated as follows:

[0106]

[0107] Figure 6 In the embodiment shown, after four 220nH inductors are connected in parallel, the total inductance is 55nH. Figure 1 Compared with the inductor L1 (1μH) shown in the figure, its discharge time is the charging time t required for the capacitor to charge. charge It is shortened from 68ns to 16ns, which means the capacitor charging rate is 4.25 times that of the original solution.

[0108] It can be seen that compared with Figure 3The prior art solution shown in the figure achieves the same function. The present invention saves two transistors in hardware (i.e. Figure 3 Q2 and Q3 in the figure), the drivers of these two transistors, and the two diodes (i.e. Figure 3 In the embodiment of the present invention, an inductor is added to the two driver control signal lines (D4, D5). Since the inductance value of the inductors (L11, L12, L13, L14) used in the scheme of the present invention is less than one-fourth of the original inductance value, the package can be made smaller, and the sum of the volumes of the four inductors used in the design is similar to the volume of the original inductor. Therefore, the circuit integration can be further improved. In addition, the reduction of discrete devices also improves the reliability of the system and reduces the probability of light pulse loss due to device failure or poor welding.

[0109] By using the scheme of the present invention, by controlling the timing of the signal, the laser LA can realize the emission of a single laser pulse signal, and can also realize the emission of any number of laser pulse signals in a short time. These situations are described in detail below.

[0110] For ease of description, Figure 6 The control end of transistor Q21 (i.e., the gate of Q21) is called the boost control port, and its input signal is called the boost control signal GateIn. The control end of transistor QA (i.e., the gate of QA) is called the light-emitting control port, and its input signal is called the light-emitting control signal Trig_In_Pro. The inductor energy storage time is called the gate value, i.e., the high level duration of the boost control signal GateIn.

[0111] There are two ways to adjust the luminous intensity of the laser LA: (1) The luminous intensity of the laser can be adjusted by adjusting the gate value, that is, the larger the gate value, the more energy the inductor stores, the more energy the inductor transfers to the capacitor C31, the higher the voltage of the capacitor C31, and the stronger the luminous intensity of the laser LA. (2) The intensity of the laser luminous intensity can be adjusted by adjusting the number of inductors connected to the circuit, for example, at least one of the four parallel inductors L11, L12, L13, and L14 can be connected in series with a switch, and the number of parallel inductors can be adjusted by the switch.

[0112] like Figure 8 FIG. 1 is a timing diagram of emitting a single pulse laser signal using the laser emitting circuit provided in an embodiment of the present invention.

[0113] For the boost control signal GateIn: at t 1 At this moment, GateIn starts to jump from low level to high level, t 1 ~t 2The stage is the energy storage time of the parallel inductor (i.e., gate value), and the gate value can be adjusted in the range of 2ns to 100ns. 2 At this moment, GateIn changes from high level to low level, the energy storage of the parallel inductor ends, and the energy storage capacitor C31 starts to be charged. 2 ~t 3 The stage is the charging time t of the parallel inductor charging the capacitor C31 charge , for example, it can be 16ns. It should be noted that the charging time is not limited to 16ns and can be set arbitrarily according to requirements.

[0114] For the light-emitting control signal Trig_In_Pro: 3 At time t, capacitor C31 is fully charged. 3 After the moment (that is, any moment after the capacitor C31 is fully charged), Trig_In_Pro can be controlled to jump from a low level to a high level, that is, the laser is controlled to emit light; Figure 8 As shown, at t 4 At this moment, Trig_In_Pro changes from low level to high level and satisfies t 4 ≥t 3 =t 1 +gate+t charge The laser emits light during the high level duration of Trig_In_Pro, and this high level duration is called the light emission control signal pulse width t pw , satisfying the following conditions: pw =t 5 -t 4 , where t 5 is the moment when the light-emitting control signal Trig_In_Pro changes from a high level to a low level, for example, t pw =10ns.

[0115] It should be noted that the pulse width of the light emitting control signal t pw Not limited to 10ns, as long as the pulse width of the light control signal t pw It only needs to be greater than or equal to the time required for the laser to emit light.

[0116] like Fig. 9 FIG. 1 is a timing diagram of emitting a double-pulse laser signal using the laser emitting circuit provided in an embodiment of the present invention.

[0117] For the boost control signal GateIn: at t 1 At this moment, GateIn starts to jump from low level to high level, t 1 ~t 2 The first stage is the energy storage time of the parallel inductor (i.e., gate value, ranging from 2ns to 100ns); at t2 At the moment, GateIn jumps from high level to low level, the parallel inductor energy storage ends, and starts to charge the energy storage capacitor C31. 3 At the moment, the parallel inductor is charged for the first time for the energy storage capacitor, and the charging time is t charge =t 3 -t 2 =16ns; the second energy storage start time of the parallel inductor t 4 Conditions to be met: 4 ≥t 1 +gate+t charge +t regain , where t regain is the inductor reverse current recovery time, that is, the time when the inductor starts to store energy for the second time t 4 It must be satisfied that at any time after the last discharge of the inductor is completed and the reverse current is restored, at t 7 At the moment GateIn jumps from high level to low level again, the second energy storage of the parallel inductor ends, and the energy storage capacitor C31 starts to be charged for the second time. 8 At the moment, the parallel inductor is used to charge the energy storage capacitor for the second time, and the charging time is t charge =t 8 -t 7 =16ns, where t 4 ~t 7 The second stage is the energy storage time of the parallel inductor (i.e., gate value, ranging from 2ns to 100ns). It should be noted that the energy storage time of the parallel inductor determines the energy stored in the parallel inductor, which also determines the energy stored in the energy storage capacitor C31. Therefore, if the double pulse light intensity energy needs to be consistent, t 7 -t 4 =t 2 -t 1 =gate.

[0118] For the light-emitting control signal Trig_In_Pro: t 3 At time t, the energy storage capacitor C31 is fully charged for the first time, and the laser LA emits light for the first time. 5 Need to meet t 3 =t 1 +gate+t charge ≤t 5 ≤t 1 +2×gate+t charge +t regain -t pw =t 7 -t pw , that is, t 5 ≥t 3 And t 5+t pw ≤t 7 ; That is, the moment of first emission t 5 It must be after the energy storage capacitor C31 is fully charged, that is, t 5 ≥t 3 , and before charging the energy storage capacitor C31 for the second time, the energy storage capacitor C31 needs to be fully discharged, that is, t 5 +t pw ≤t 7 ; at t 8 At this moment, the energy storage capacitor C31 is fully charged for the second time, and the second light emission time is t 9 The condition to be satisfied is t 9 ≥t 8 =t 1 +2×gate+2×t charge +t regain , that is, the second luminescence moment t 9 It must be after the energy storage capacitor C31 is fully charged for the second time, that is, t 9 ≥t 8 ; Among them, the light control signal pulse width t pw =t 6 -t 5 =t 10 -t 9 , where t 6 is the moment when the light-emitting control signal Trig_In_Pro changes from a high level to a low level for the first time, t 10 It is the moment when the light-emitting control signal Trig_In_Pro changes from a high level to a low level for the second time.

[0119] like Fig.10 , which is a timing diagram of emitting three-pulse laser signals using the laser emitting circuit provided in an embodiment of the present invention.

[0120] For the boost control signal GateIn: at t 1 At this moment, GateIn starts to jump from low level to high level. 2 At this moment, the GateIn signal changes from high level to low level, t 1 ~t 2 The first stage is the energy storage time of the parallel inductor (i.e., gate value, ranging from 2ns to 100ns). 2 At the moment, the first energy storage of the parallel inductor ends and the energy storage capacitor C31 starts to be charged for the first time. 3 At the moment, the parallel inductor is charged for the first time for the energy storage capacitor, and the charging time is t charge =16ns; the second energy storage start time of the parallel inductor t 4 The condition to be satisfied is t4 ≥t 1 +gate+t charge +t regain , at t 7 At the moment, the second energy storage of the parallel inductor ends, and the energy storage capacitor C31 starts to be charged for the second time. 8 At the moment, the parallel inductor is used to charge the energy storage capacitor for the second time, and the charging time is t charge =t 8 -t 7 =16ns, where t 4 ~t 7 The second stage is the energy storage time of the parallel inductor (i.e., gate value, ranging from 2ns to 100ns); the third energy storage start time of the parallel inductor is t 9 The condition to be satisfied is t 9 ≥t 1 +2×gate+2×t charge +2×t regain , t 12 At time t, the third energy storage of the parallel inductor ends and the energy storage capacitor C31 starts to be charged for the third time. 13 At this moment, the parallel inductor is used to charge the energy storage capacitor for the third time, and the charging time is t charge =t 13 -t 12 =16ns, where t 9 ~t 12 The stage is the third energy storage time of the parallel inductor (i.e., gate value, ranging from 2ns to 100ns). In order to ensure the consistency of the three pulse light intensity, this embodiment requires t 12 -t 9 =t 7 -t 4 =t 2 -t 1 =gate. It should be noted that the present application is not limited to requiring the energy of each pulse light to be consistent, so the energy storage time of each parallel inductor may be different.

[0121] For the light-emitting control signal Trig_In_Pro: 3 At this moment, the energy storage capacitor C31 is fully charged for the first time, and the first light emission moment is t 5 It must be after the energy storage capacitor C31 is fully charged, that is, t 5 ≥t 3 , and before charging the energy storage capacitor C31 for the second time, the energy storage capacitor C31 needs to be fully discharged, that is, t 5 +t pw ≤t 7 , the first luminous moment t 5 Need to meet t 1+gate+t charge ≤t 5 ≤t 1 +2×gate+t charge +t regain -t pw ;t 8 At time t, the energy storage capacitor C31 is fully charged for the second time. Similarly, the second light emission time t 10 It must be after the energy storage capacitor C31 is fully charged for the second time, that is, t 10 ≥t 7 , and before charging the energy storage capacitor C31 for the third time, the energy storage capacitor C31 needs to be fully discharged, that is, t 10 +t pw ≤t 12 , the second luminous moment t 10 The condition to be satisfied is t 1 +2×gate+2×t charge +t regain ≤t 10 ≤t 1 +3×gate+2×t charge +2×t regain -t pw ;t 13 At time t, the energy storage capacitor C31 is fully charged for the third time. Similarly, at time t 14 It must be after the energy storage capacitor C31 is fully charged for the third time, that is, t 14 ≥t 12 , the third luminous moment t 14 The condition to be satisfied is t 14 ≥t 1 +3×gate+3×t charge +2×t regain ; Among them, the light control signal pulse width t pw =t 6 -t 5 =t 11 -t 10 =t 15 -t 14 , where t 6 is the moment when the light-emitting control signal Trig_In_Pro changes from a high level to a low level for the first time, t 11 is the moment when the light-emitting control signal Trig_In_Pro changes from high level to low level for the second time, t 15 This is the moment when the light-emitting control signal Trig_In_Pro changes from a high level to a low level for the third time.

[0122] Without loss of generality, using the solution of the present invention, any number of pulsed laser signals can be emitted within a short period of time, and certain timing requirements need to be met.

[0123] Among them, the timing logic constraints of the boost control signal GateIn are as follows (the rising edge of the signal is the start time, and the falling edge is the end time):

[0124] The first energy storage of the inductor:

[0125] Start time t start1 =t d

[0126] End time t stop1 =t d +gate

[0127] The second energy storage of inductor:

[0128] Start time t start2 ≥t d +gate+t charge +t regain

[0129] End time t stop2 =t start2 +gate≥t d +2×gate+t charge +t regain

[0130] The third energy storage of inductor:

[0131] Start time t start3 ≥t d +2×gate+2×t charge +2×t regain

[0132] End time t stop3 =t start3 +gate≥t d +3×gate+2×t charge +2×t regain

[0133] …

[0134] The Nth energy storage of the inductor:

[0135] Start time t startN ≥t d +(N-1)×gate+(N-1)×t charge +(N-1)×t regain

[0136] End time t stopN =tstartN +gate≥t d +N×gate+(N-1)×t charge +(N-1)×t regain

[0137] In order to ensure the consistency of the intensity of N pulses, t startN -t stopN =…=t stop3 -t start3 =t stop2 -t start2 =t stop1 -t start1 =gate.

[0138] Among them, the timing logic constraints of the light-emitting control signal Trig_In_Pro are as follows:

[0139] The laser emits light for the first time:

[0140] Time lower limit constraint t s1 ≥t stop1 +t charge =t d +gate+t charge

[0141] Time upper limit constraint t s1 ≤t stop2 -t pw =t d +2×gate+t charge +t regain -t pw

[0142] That is, s1 +t pw ≤t stop2 That is to say, the electricity in the capacitor needs to be discharged before charging the capacitor for the second time, that is, the first pulse must be emitted before the second charging of the inductor is completed.

[0143] The laser emits light for the second time:

[0144] Time lower limit constraint t s2 ≥t stop2 +t charge =t d +2×gate+2×t charge +t regain

[0145] Time upper limit constraint t s2 ≤t stop3 -t pw =t d +3×gate+2×t charge+2×t regain -t pw

[0146] That is, s2 +t pw ≤t stop3 That is to say, before charging the capacitor for the third time, the electricity in the capacitor needs to be discharged, that is, the second pulse must be emitted before the third charging of the inductor is completed.

[0147] The laser emits light for the third time:

[0148] Time lower limit constraint t s3 ≥t stop3 +t charge =t d +3×gate+3×t charge +2×t regain

[0149] Time upper limit constraint t s3 ≤t stop4 -t pw =t d +4×gate+3×t charge +3×t regain -t pw

[0150] That is, s3 +t pw ≤t stop4 That is to say, before charging the capacitor for the fourth time, the electricity in the capacitor needs to be discharged, that is, the third pulse must be emitted before the fourth charging of the inductor is completed.

[0151] …

[0152] The laser emits light for the Nth time:

[0153] Time lower limit constraint t sN ≥t stopN +t charge =t d +N×gate+N×t charge +(N-1)×t regain

[0154] Time upper limit constraint t sN ≤t stop(N+1) -t pw =t d t d +(N+1)×gate+N×t charge +N×t regain -t pw

[0155] That is, sN +tpw ≤t stop(N+1) That is to say, before charging the capacitor for the N+1th time, the electricity in the capacitor needs to be discharged, that is, the Nth pulse must be emitted before the N+1th charging of the inductor is completed.

[0156] In the above formulas, t d Indicates the delay time of the boost control signal GateIn, t pw represents the pulse width of the light-emitting control signal Trig_In_Pro, gate represents the inductor energy storage time, t charge Indicates the charging time of energy storage capacitor C31, t regain Indicates the inductor reverse current recovery time.

[0157] Let the encoding time be t code , then the calculation formula for the maximum number of pulses N that can be sent within the encoding time is as follows:

[0158]

[0159] In the above formula, taking an integer for N is t code The maximum number of pulses that can be sent within a certain period of time. For example, t code =700ns, gate = 50ns, t code The maximum number of pulses that can be sent within a time period is 8.

[0160] Increasing the number of pulses sent during the coding time is beneficial to increasing the coding modulation complexity and the system's anti-interference ability. The simultaneous emission of multi-channel lasers is beneficial to solving the problem of crosstalk between transmitters and receivers and enhancing the stability and reliability of the system.

[0161] It should be noted that in the above examples, the sizes of the multiple inductors connected in parallel can be the same or different. When the sizes of the multiple inductors are the same, the size of the current inside each inductor and the energy obtained are the same; when the sizes of the multiple inductors are different, the sizes of the current inside different inductors and the energy obtained will be different, but it is only necessary to ensure that the maximum total energy obtained by the multiple inductors is greater than or equal to the energy required for the transmitting unit to transmit a pulse. In addition, in the case of continuous emission of multiple laser pulses, the above timing constraints can be met.

[0162] In addition, it should be noted that in actual applications, the charging time can be controlled to be the same each time (such as the above examples), or the charging time can be controlled to be different each time or partially the same and partially different. The specific setting can be based on application needs and is not limited in the embodiments of the present invention.

[0163] Accordingly, an embodiment of the present invention further provides a control method for the laser emitting circuit described above. Fig.11 A flow chart of the control method is shown, comprising the following steps:

[0164] First, in step S121, it is an inductor charging stage: the plurality of parallel-connected inductors are charged by the external power supply so that the inductors obtain energy;

[0165] Then, in step S122, which is the inductive discharge stage: the energy is transmitted to the energy storage unit;

[0166] Then, in step S123, it is the laser emission stage: after the energy storage unit completes energy storage, laser pulses are emitted using the energy stored in the energy storage unit.

[0167] Specifically, after the energy storage unit completes energy storage, the energy storage unit is electrically connected to the laser emission module, so that the laser emission module emits laser pulses. In other words, the energy storage unit provides energy to the laser emission module to achieve laser emission.

[0168] Furthermore, after the laser pulse is emitted, the energy storage unit needs to be disconnected from the laser emission module so that the inductor can obtain energy again and transfer the energy to the energy storage capacitor, so that the energy storage capacitor is charged again to provide energy for the laser emission module and realize the emission of multiple laser pulses.

[0169] The laser pulses may be emitted multiple times by repeatedly executing the inductive charging stage to the laser emitting stage. Moreover, the next inductive discharging stage needs to be performed after the laser emitting stage is completed.

[0170] In a non-limiting embodiment, in the above step 121, i.e., the inductive charging stage, the charging duration of the inductive charging stage may be further adjusted according to the energy required for emitting the laser pulse.

[0171] In addition, it should be noted that the charging duration of the inductive charging stage corresponding to each emission of the laser pulse can remain the same or different, which can be determined according to actual application needs.

[0172] It can be seen that the laser emission circuit and control method thereof provided by the embodiments of the present invention can improve the inductive energy storage and capacitive charging efficiency of the power supply module in the laser emission circuit, and improve the circuit integration and reliability.

[0173] Accordingly, an embodiment of the present invention further provides a laser radar, such as Fig.12 The figure shows a schematic diagram of the structure of the laser radar.

[0174] The laser radar 130 includes the laser emitting circuit 131 and the laser receiving circuit 132 in the above-mentioned embodiments.

[0175] The laser emitting circuit 131 is used to emit laser pulses;

[0176] The laser receiving circuit 132 is used to receive the laser pulse.

[0177] The laser emission circuit 131 in the embodiment of the present invention obtains energy from an external power supply by means of multiple inductors in parallel, and transfers the energy to an energy storage capacitor, which provides emission energy for the laser emission module. It can also continuously emit multiple laser pulses in a short period of time, and the intervals and / or intensities of the multiple laser pulses can be the same or different.

[0178] Correspondingly, the laser receiving circuit 132 in the embodiment of the present invention can further determine whether the pulse interval and / or pulse intensity of the received pulse corresponds to the pulse interval and / or pulse intensity of the transmitted pulse, thereby determining whether the received signal is a signal emitted by the laser radar itself, thereby achieving the purpose of anti-interference.

[0179] It should be understood that the term "and / or" in this article is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article indicates that the associated objects before and after are in an "or" relationship.

[0180] The “plurality” mentioned in the embodiments of the present invention refers to two or more than two.

[0181] The first, second, etc. descriptions appearing in the embodiments of the present invention are only used for illustration and distinction of the description objects. There is no order, nor does it indicate any special limitation on the number of devices in the embodiments of the present invention, and cannot constitute any limitation on the embodiments of the present invention.

[0182] The “connection” in the embodiments of the present invention refers to various connection modes such as direct connection or indirect connection to achieve communication between devices, and the embodiments of the present invention do not impose any limitation on this.

[0183] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A laser emission circuit, characterized in that: The laser emission circuit comprises: a power supply module and a laser emission module; the power supply module comprises: an energy acquisition unit, a boost control unit, and an energy storage unit, the energy acquisition unit comprises a plurality of parallel inductors; the laser emission module comprises an emission unit and an emission control unit; The boost control unit is used to control the energy acquisition unit to acquire energy from an external power source, or to control the energy acquisition unit to transfer the energy to the energy storage unit; The emission control unit is used to control the emission unit to emit laser pulses using the energy stored in the energy storage unit after the energy storage unit completes energy storage.

2. The laser emitting circuit according to claim 1, characterized in that: The inductance values ​​of the multiple inductors are the same.

3. The laser emitting circuit according to claim 1, characterized in that: The boost control unit comprises: a first switch subunit and a first drive subunit; The first driving subunit is used to drive the first switch subunit to close or open; The energy acquisition unit acquires energy from an external power source after the first switch subunit is closed; and transmits the energy to the energy storage unit after the first switch subunit is opened.

4. The laser emitting circuit according to claim 3, characterized in that: The transmitting control unit comprises: a second switch subunit and a second driving subunit; The second driving subunit is used to drive the second switch subunit to close or open; The emission unit emits laser pulses after the second switch subunit is closed.

5. The laser emitting circuit according to claim 4, characterized in that: The first switch subunit and the second switch subunit are transistors.

6. The laser emitting circuit according to claim 1, characterized in that: The laser pulse is a single pulse or multiple pulses.

7. A laser emission circuit control method, characterized in that: The laser emission circuit comprises: a power supply module and a laser emission module; the power supply module comprises: an energy acquisition unit, a boost control unit, and an energy storage unit, the energy acquisition unit comprises a plurality of parallel inductors, the boost control unit is used to control the energy acquisition unit to acquire energy from an external power source, or to control the energy acquisition unit to transfer the energy to the energy storage unit; the laser emission module comprises an emission unit and an emission control unit, the emission control unit is used to control the emission unit to emit laser pulses using the energy stored in the energy storage unit after the energy storage unit completes energy storage; The method comprises: Inductor charging stage: using the external power supply to charge the multiple parallel-connected inductors so that the inductors obtain energy; Inductive discharge stage: transferring the energy to the energy storage unit; Laser emission stage: after the energy storage unit completes energy storage, laser pulses are emitted using the energy stored in the energy storage unit.

8. The control method according to claim 7, characterized in that: The inductive charging stage also includes: The charging duration of the inductive charging stage is adjusted according to the energy required for emitting the laser pulse.

9. The control method according to claim 7, characterized in that: The laser emission stage includes: After the energy storage unit completes energy storage, the energy storage unit is electrically connected to the laser emission module, so that the laser emission module emits laser pulses.

10. The control method according to claim 9, characterized in that: The laser emission stage also includes: After the laser pulse is emitted, the energy storage unit is disconnected from the laser emission module.

11. The control method according to any one of claims 7 to 10, characterized in that: The method further comprises: The inductor charging stage to the laser emitting stage are repeatedly executed to emit the laser pulses multiple times.

12. The control method according to claim 11, characterized in that: The charging duration of the inductive charging stage corresponding to each emission of the laser pulse remains the same or different.

13. The control method according to claim 11, characterized in that: The method further comprises: After the laser emission phase is completed, the next inductive discharge phase is performed.

14. A laser radar, characterized in that: The laser radar comprises a laser transmitting circuit as described in any one of claims 1 to 7, and a laser receiving circuit; The laser emission circuit is used to emit laser pulses; The laser receiving circuit is used to receive the laser pulse.

Images