Laser driver circuit, transmitting device and laser radar

Abstract

The application discloses a laser driver circuit, a transmitting device and a laser radar. The laser driver circuit is coupled with an energy storage unit and a laser, and comprises a driving unit adapted to turn on a light-emitting path comprising the energy storage unit and the laser based on a trigger signal; a first comparator adapted to compare an output signal at an output end of the driving circuit with a first threshold value and output a first detection signal based on a comparison result; a second comparator adapted to compare the output signal at the output end of the driving circuit with a second threshold value and output a second detection signal based on a comparison result; and a state judging unit adapted to output a working state signal of the driving unit and / or the laser according to the first detection signal and the second detection signal. The circuit can enhance the reliability of a laser transmitting end circuit.

Description

Technical Field

[0001] This specification relates to the field of lidar technology, and in particular to a laser driver circuit, a transmitting device, and a lidar. Background Technology

[0002] LiDAR (Light Detection and Ranging) is a sensor that uses lasers to achieve precise distance measurement. LiDAR emits laser pulses, which are reflected back from surrounding objects. By measuring the time it takes for the laser to reach and return to each object, the precise distance to the object can be calculated. LiDAR emits tens of thousands of pulses per second; by collecting these distance measurements, a three-dimensional environment model, or point cloud, can be constructed.

[0003] In lidar ranging applications, to achieve higher ranging accuracy, longer detection distances, and higher scanning frequencies, lasers are required to generate laser pulse signals with fast leading edges, high peak power, and narrow pulse widths. Since the performance of lasers themselves is generally good enough to meet these requirements, the main influencing factor on laser pulse signal quality is currently the performance of the driving circuit. Summary of the Invention

[0004] In view of this, the embodiments of this specification provide a laser driving circuit, a transmitting device, and a lidar, which can detect circuit faults, promptly identify abnormalities, and thus enhance the reliability of the laser transmitting circuit.

[0005] First, this specification provides a laser driving circuit coupled to an energy storage unit and a laser, the laser driving circuit comprising:

[0006] A driving unit is adapted to activate the light-emitting path including the energy storage unit and the laser based on a trigger signal;

[0007] A first comparator is adapted to compare the output signal of the laser driving circuit with a first threshold, and output a first detection signal based on the comparison result. The first threshold is close to and slightly smaller than the output signal value corresponding to the laser emitting the highest luminous energy.

[0008] The second comparator is adapted to compare the output signal of the laser driving circuit with a second threshold, and output a second detection signal based on the comparison result. The second threshold is less than the first threshold and slightly greater than the output signal value corresponding to the laser emitting the lowest luminous energy.

[0009] The status determination unit is adapted to output the operating status signal of the driving unit and / or the laser based on the first detection signal and the second detection signal.

[0010] Optionally, the state determination unit includes a logic circuit subunit and a timing circuit subunit, wherein:

[0011] The logic circuit subunit includes a latch module and a logic module. The latch module is adapted to latch the first detection signal and the second detection signal in the current time, and after receiving the second delay signal, to perform the operation of latching the first detection signal and the second detection signal in the next time. The logic module is coupled to the latch module and is adapted to output the working status signal of the driving unit and / or the laser after performing logical operations based on the first detection signal and the second detection signal.

[0012] The timing circuit subunit includes a delay module and a status output module, wherein: the delay module is adapted to generate a first delay signal and a second delay signal after delaying the trigger signal; the status output module is adapted to latch the current operating status signal of the driving unit and / or the laser, and after receiving the first delay signal, perform the operation of latching the next operating status signal of the driving unit and / or the laser.

[0013] Optionally, the duration of the second delay signal is greater than the duration of the first delay signal, and less than the time interval between two consecutive adjacent trigger signals.

[0014] Optionally, the latch module includes: a first D flip-flop and a second D flip-flop; the logic module includes a gate logic circuit module, wherein:

[0015] The first D flip-flop has its D input terminal coupled to the power supply terminal, its clock signal input terminal adapted to input the first detection signal and is triggered on the rising edge, and its reset signal terminal adapted to input the second delay signal;

[0016] The second D flip-flop has its D input terminal coupled to the power supply terminal, its clock signal input terminal adapted to input the second detection signal and is triggered on the rising edge, and its reset signal terminal adapted to input the second delay signal;

[0017] The gate logic circuit module is adapted to output the corresponding operating status signal of the driving unit and / or the laser to the corresponding input terminal of the timing circuit subunit based on the output results of the first D flip-flop and the second D flip-flop, including a first output terminal, a second output terminal and a third output terminal.

[0018] Optionally, the delay module includes: a first inverter and a second inverter, wherein:

[0019] The first inverter has an input terminal adapted to receive the trigger signal and an output terminal adapted to output the first delay signal.

[0020] The second inverter has its input terminal adapted to receive the trigger signal and its output terminal adapted to output the second delay signal;

[0021] The status output module includes: a third D flip-flop, a fourth D flip-flop, and a fifth D flip-flop, wherein:

[0022] The third D flip-flop has an input terminal adapted to be coupled to the first output terminal of the gate logic circuit, a clock signal input terminal adapted to input the first delay signal, and an output terminal adapted to output a laser open-circuit signal characterizing that the laser is in an open-circuit state.

[0023] The fourth D flip-flop has an input terminal adapted to be coupled to the second output terminal of the gate logic circuit, a clock signal input terminal adapted to input the first delay signal, and an output terminal adapted to output a driving unit open circuit signal that indicates that the driving unit is in an open circuit state.

[0024] The fifth D flip-flop has its input terminal adapted to be coupled to the third output terminal of the gate logic circuit, its clock signal input terminal adapted to input the first delay signal, and its output terminal adapted to output a signal characterizing that the laser is in normal working state.

[0025] Optionally, the laser driving circuit further includes: a first voltage divider unit, a second voltage divider unit, and a third voltage divider unit, wherein:

[0026] The first voltage divider unit is coupled between the power supply and ground, and is coupled to the inverting input terminal of the first comparator through the first voltage divider terminal;

[0027] The second voltage divider unit is coupled between the power supply and ground, and is coupled to the inverting input terminal of the second comparator through the second voltage divider terminal;

[0028] The third voltage divider unit is coupled between the output terminal of the laser driver circuit and ground, and is coupled to the non-inverting input terminal of the first comparator and the non-inverting input terminal of the second comparator respectively through the third voltage divider terminal.

[0029] Optionally, the first voltage divider unit includes a first resistor and a second resistor connected in series, and the first voltage divider terminal is disposed between the first resistor and the second resistor;

[0030] The second voltage divider unit includes a third resistor and a fourth resistor connected in series, and the second voltage divider terminal is disposed between the third resistor and the fourth resistor;

[0031] The third voltage divider unit includes a fifth resistor and a sixth resistor connected in series, and the third voltage divider terminal is disposed between the fifth resistor and the sixth resistor.

[0032] Optionally, the first voltage divider unit includes a first capacitor and a second capacitor connected in series, and the first voltage divider terminal is disposed between the first capacitor and the second capacitor;

[0033] The second voltage divider unit includes a third capacitor and a fourth capacitor connected in series, and the second voltage divider terminal is disposed between the third capacitor and the fourth capacitor;

[0034] The third voltage divider unit includes a fifth capacitor and a sixth capacitor connected in series, and the third voltage divider terminal is disposed between the fifth capacitor and the sixth capacitor.

[0035] This specification also provides a transmitting device, including:

[0036] Laser;

[0037] The laser driving circuit described in any of the foregoing embodiments is coupled to a power supply, the laser, the energy storage unit, and a controller, and includes: a driving unit, a first comparator, a second comparator, and a status determination unit. The laser driving circuit is adapted to drive the laser to emit light based on a trigger signal and output the operating status signal of the driving unit and / or the laser to the controller so as to perform corresponding fault protection operations when it is determined that the driving unit and / or the laser is in a fault state.

[0038] The energy storage unit is coupled to the laser and is adapted to form a charging path with the power supply and a light-emitting path with the laser; and the energy storage unit is adapted to be charged by the power supply through the charging path when the driving unit is turned off, and to be discharged through the light-emitting path when the driving unit is turned on, so that the laser emits light pulses.

[0039] This specification also provides a lidar system, comprising: a light emitting device, a driving device, an energy storage device, and a controller, wherein:

[0040] The light emitting device includes multiple lasers;

[0041] The driving device includes multiple driving circuits, each driving circuit being coupled to the energy storage device, the controller, and a corresponding laser. Each driving circuit includes a driving unit, a first comparator, a second comparator, and a status judgment unit. Specifically, it adopts the laser driving circuit described in any of the foregoing embodiments, drives the corresponding laser to emit light based on a trigger signal, and outputs the corresponding driving unit and / or the laser's operating status signal to the controller, so as to perform corresponding fault protection operations when it is determined that the corresponding driving circuit is in a fault state.

[0042] An energy storage device includes an energy storage unit coupled to at least one of the lasers, adapted to form a charging path with a power source and a light emission path with the coupled lasers, wherein the energy storage unit is adapted to charge via the power source through the charging path when the coupled driving unit is turned off, and to discharge via the light emission path when the coupled driving unit is turned on, so that the coupled lasers emit light pulses.

[0043] The controller is adapted to be coupled to the driving device, and is adapted to output a trigger signal to the driving unit of the corresponding driving circuit based on preset emission control parameters to drive the corresponding laser to emit light. Based on the received operating status signal of the driving unit and / or the laser, when it is determined that the driving circuit and / or the laser is in a fault state, the controller performs the corresponding fault protection operation.

[0044] Optionally, the controller is adapted to output a transmission control signal to control the corresponding transmission channel to stop working when it determines that the laser is open or / and the driving unit is open based on the received operating status signals of the driving unit and / or the laser.

[0045] Optionally, the controller is also adapted to output a corresponding open-circuit alarm signal when it determines that the laser is open or / and the drive circuit is open based on the received operating status signals of the drive unit and / or the laser.

[0046] The laser driving circuit described in this specification uses a driving unit to activate the light-emitting path including the energy storage unit and the laser. A first comparator compares the output signal of the laser driving circuit with a first threshold, outputting a first detection signal based on the comparison result. A second comparator compares the output signal of the laser driving circuit with a second threshold, outputting a second detection signal based on the comparison result. A status judgment unit outputs the operating status signal of the driving unit and / or the laser based on the first and second detection signals. By directly detecting the output signal of the laser driving circuit and comparing it with the preset first and second thresholds, the operating status can be monitored in real time, enabling fault detection and timely identification of abnormalities, thereby enhancing the reliability of the laser emitting circuit. Furthermore, since only two comparators are needed in the laser driving circuit to determine whether the driving unit and / or the laser is working properly, the structure is simple, easy to implement, and has a low cost.

[0047] Further, the state determination unit includes a logic circuit subunit and a timing circuit subunit. The logic circuit subunit includes a latch module and a logic module. The timing circuit subunit includes a delay module and a state output module. The delay module generates a first delayed signal and a second delayed signal based on the trigger signal after a delay. The latch module latches the first and second detection signals for the current time. Upon receiving the second delayed signal, it latches the next first and second detection signals. The logic module is adapted to perform logical operations based on the first and second detection signals and output the operating state signal of the driving unit / or the laser. The status output module latches the current operating status signal of the driving unit and / or the laser output by the logic module, and after receiving the first delay signal, performs the operation of latching the next operating status signal of the driving unit and / or the laser. The duration of the second delay signal is longer than the duration of the first delay signal and shorter than the time interval between two consecutive trigger signals. By adopting the above scheme, for non-continuously emitted laser pulses, the timing coordination of the latch module, the logic module and the status output module can effectively obtain the instantaneous changing operating status of the laser driving circuit and the laser, avoid omissions, and ensure the accuracy and reliability of fault monitoring results.

[0048] Furthermore, by using a second delay signal whose duration is greater than the duration of the first delay signal and less than the time interval between two consecutive adjacent trigger signals, the timing requirements of each device are ensured. This ensures that the working status signal output of the current driving unit and / or laser is completed before the next trigger signal arrives, thereby enabling the monitoring of the driving circuit used for pulse ranging.

[0049] Furthermore, the first and second voltage divider units are respectively coupled between the power supply terminal and ground, and the first voltage divider terminal is coupled to the inverting input terminal of the first comparator, and the second voltage divider terminal is coupled to the inverting input terminal of the second comparator. The third voltage divider unit, which is coupled between the output terminal of the laser driver circuit and ground, is coupled to the non-inverting input terminals of the first and second comparators respectively. By adopting the above scheme, the first and second comparators, together with the first, second, and third voltage divider units, can achieve the detection of the operating status of the laser driver circuit and the laser operating in a high-voltage environment with low power consumption. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0051] Figure 1 A schematic diagram of a laser driving circuit is shown.

[0052] Figures 2 to 4 The equivalent circuit diagram of the laser driving circuit corresponding to different working states of the laser is shown.

[0053] Figure 5 A schematic diagram of a laser driving circuit according to an embodiment of this specification is shown;

[0054] Figure 6 A table showing the operating status signal output of a laser driving circuit according to an embodiment of this specification is provided.

[0055] Figure 7 A schematic diagram of the structure of a laser driving circuit in a specific application scenario is shown in an embodiment of this specification;

[0056] Figure 8 A schematic diagram of the structure of a laser driving circuit in another specific application scenario is shown in an embodiment of this specification;

[0057] Figure 9 The diagram shows the waveform of the laser drive circuit when both the drive unit and the laser are in normal working condition, as illustrated in the embodiments of this specification.

[0058] Figure 10 The following diagram shows the voltage waveforms at corresponding monitoring points in the laser drive circuit when both the drive unit and the laser are in normal working condition, as illustrated in the embodiments of this specification.

[0059] Figure 11 The timing diagram of the corresponding signals in the laser drive circuit is shown when both the drive unit and the laser are in normal working condition in the embodiments of this specification.

[0060] Figure 12 The waveform diagram of the laser drive circuit with the laser open circuit in the embodiments of this specification is shown;

[0061] Figure 13 The following diagram shows the voltage waveforms at corresponding monitoring points in the laser drive circuit when the laser is open-circuited, as illustrated in the embodiments of this specification.

[0062] Figure 14The timing diagram of the corresponding signals in the laser drive circuit when the laser is open-circuited is shown in the embodiments of this specification;

[0063] Figure 15 The waveform diagram of the laser driving circuit when the driving unit is open is shown in the embodiment of this specification;

[0064] Figure 16 The voltage waveforms at corresponding monitoring points in the laser drive circuit when the drive unit is open-circuited, as shown in the embodiments of this specification, are illustrated.

[0065] Figure 17 The timing diagram of the corresponding signals in the laser drive circuit when the drive unit is open in the embodiment of this specification is shown;

[0066] Figure 18 A schematic diagram of the structure of a launching device according to an embodiment of this specification is shown;

[0067] Figure 19 A schematic diagram of the structure of a lidar according to an embodiment of this specification is shown. Detailed Implementation

[0068] LiDAR has become a core sensor device in many fields such as autonomous driving, mapping, smart cities, vehicle-to-everything (V2X), robotics, and security. Therefore, the normal and stable operation of LiDAR, including the LiDAR transmitter, is a necessary guarantee for the normal operation of equipment equipped with LiDAR in various fields. However, at present, there is no corresponding monitoring and guarantee mechanism for the laser driver circuit of the laser transmitter.

[0069] To make the problems of the prior art clearer to those skilled in the art, the following description is based on a narrow pulse width driving circuit.

[0070] Reference Figure 1 The schematic diagram of the laser driving circuit shown is a narrow pulse width driving circuit 10, which includes a gate driver 11, a driving switch 12 (e.g., a power FET), a laser LD, and an energy storage capacitor C. HV .

[0071] The emission energy of the laser LD can be changed by adjusting the pulse width of the trigger signal Tr or the voltage at the power supply HV terminal. Specifically, the width of each trigger signal Tr corresponds to the duration of laser LD emission. The drive switch 12 can only be opened and the laser LD can emit light when there is an input to the trigger signal Tr. Widening the trigger signal Tr limits the interval between adjacent pulses, increasing the dead time of the measurement and preventing the achievement of a higher trigger frequency. Since the emission power is proportional to the current flowing through the laser LD, changing the pulse width of the drive input trigger signal Tr proportionally changes the emission energy.

[0072] When the gate driver 11 does not receive the trigger signal Tr, the drive switch 12 is not turned on, and the charging circuit (power supply HV → capacitor C) is open. HV →GND) is turned on, and the power supply HV is the energy storage capacitor C HV When charging, the laser LD does not emit light; when the gate driver 11 receives a trigger signal Tr, the drive switch 12 is turned on, and the discharge circuit (capacitor C) is activated. HV →Laser LD→Drive switch 12→GND) is turned on by the energy storage diode C HV Power is supplied to the laser LD, and the laser LD emits light.

[0073] As can be seen from the above process, for the lidar to operate normally, both the drive switch 12 and the laser LD need to be in normal working condition simultaneously. If either of them malfunctions, such as an open circuit, it will cause a dead wire in one of the lidar lines (i.e., the laser LD in the channel corresponding to the input trigger signal Tr will not emit light), thus leading to ranging errors. Therefore, during lidar operation, it is necessary to determine whether the drive switch 12 and the laser LD are in normal working condition.

[0074] Reference Figures 2 to 4 The diagram shows the equivalent circuit diagrams corresponding to different operating states when the laser driving circuit drives the laser. In this embodiment, the laser LD is driven by a driving switch PMOS. Since the laser radar requires a pulse signal to drive it, the driving transistor PMOS can only be turned on when the gate of the driving transistor PMOS receives the trigger signal Tr. Only then can the discharge circuit, i.e., capacitor → driving switch PMOS → laser LD → ground GND circuit, be turned on, and the laser LD can emit light.

[0075] Specifically, Figure 2 Subgraphs (a) and (b) in the diagram show the equivalent circuit diagrams with the driving switch PMOS in the normal state and the laser LD in the normal state and open circuit state, respectively. Figure 3Subgraphs (a) and (b) show the equivalent circuit diagrams with the drive switch PMOS in a short-circuit state and the laser LD in a normal state and an open-circuit state, respectively. Figure 4 Subgraphs (a) to (b) in the figure show the equivalent circuit diagrams of the drive switch PMOS in the open circuit state and the laser LD in the normal state and the open circuit state, respectively. In the figure, default indicates that the corresponding drive circuit does not receive the trigger signal Tr, trigger indicates that the corresponding drive circuit has the trigger signal Tr, the resistor R represents the parasitic resistance in the circuit, V and I in the row corresponding to default correspond to the voltage and current when there is no trigger signal Tr, respectively, and V and I in the row corresponding to trigger correspond to the voltage and current when there is a trigger signal Tr, respectively.

[0076] by Figure 2 Taking (a) as an example, both the driving switch PMOS and the laser LD are in normal working condition. However, since there is no trigger signal input to the gate of the driving transistor PMOS, the voltage V and current I at its output terminal are both zero, and the laser LD does not emit light. When there is a trigger signal Tr input to the gate of the driving transistor PMOS, the driving switch PMOS is turned on, and the discharge path is opened, that is, the path of capacitor → driving switch PMOS → laser LD → ground GND is opened, and the laser LD emits light, and its output voltage V is V. N The current I is I N .

[0077] The inventor discovered through research and practice that, for example Figure 4 As shown, when the PMOS drive switch is in the open-circuit state, the output voltage is close to 0V. Figures 2 to 4 As shown in sub-figure (b), when only the laser LD is open-circuited, the voltage at the corresponding output terminal is close to the power supply voltage HV. Therefore, by detecting the voltage value at the output terminal of the drive circuit, it can be determined whether the drive switch PMOS and the laser LD are in an open-circuit state.

[0078] However, there is currently no corresponding monitoring and safeguard mechanism.

[0079] Based on this, the embodiments of this specification provide corresponding laser emission monitoring and circuit protection schemes. By setting a comparator in the laser driving circuit (hereinafter referred to as the driving circuit) to compare the output signal of the driving circuit with a first threshold and a second threshold respectively, and outputting a first detection signal and a second detection signal based on the comparison result, and the state judgment unit outputting the working state signal of the driving unit and / or the laser based on the first detection signal and the second detection signal, it is possible to realize real-time monitoring of the working state of the laser driving circuit and the laser, and to detect abnormalities in a timely manner, thereby enhancing the reliability of the laser emitting circuit.

[0080] To enable those skilled in the art to better understand the concepts, advantages, and implementation schemes of the solutions provided in this specification, the principles of the laser driving circuits, lidar, and other solutions provided in the embodiments of this specification will be described in detail and illustrated with reference to the accompanying drawings and specific examples.

[0081] First, in some embodiments of this specification, reference is made to Figure 5 The diagram shows a block diagram of a laser driving circuit. The laser driving circuit 50 is adapted to drive a laser 5A, and the power supply 5H can provide the operating voltage for the laser driving circuit. Specifically, the laser driving circuit 50 may include: a driving unit 5D, a first comparator U4, a second comparator U5, and a state determination unit U0, wherein:

[0082] The driving unit 5D is adapted to conduct the light-emitting path including the energy storage unit 5B and the laser 5A based on the trigger signal Tr.

[0083] The first comparator U4 is adapted to compare the output signal of the drive circuit with a first threshold, and output a first detection signal Comp1 based on the comparison result. The first threshold is close to and slightly smaller than the output signal value corresponding to the highest luminous energy emitted by the laser. For example, the first threshold can be set to 85% to 99% of the highest luminous energy emitted by the laser.

[0084] The second comparator U5 is adapted to compare the output signal of the drive circuit with a second threshold, and output a second detection signal Comp2 based on the comparison result. The second threshold is less than the first threshold and slightly greater than the output signal value corresponding to the minimum luminous energy emitted by the laser. The magnitude of the second threshold is related to both eye safety and circuit complexity. For eye safety, it should be as close as possible to the minimum luminous energy emitted by the laser; to reduce circuit complexity and avoid false alarms, it should be as far away as possible.

[0085] The state determination unit U0 is adapted to output the operating state signal S of the driving unit and / or the laser based on the first detection signal Comp1 and the second detection signal Comp2.

[0086] As can be seen from the above embodiment, the first comparator U4 compares the output signal of the laser driving circuit with the first threshold, and outputs the first detection signal Comp1 based on the comparison result. The second comparator U5 compares the output signal of the laser driving circuit with the second threshold, and outputs the second detection signal Comp2 based on the comparison result. The state judgment unit U0 outputs the working state signal of the driving unit 5D and / or the laser LD according to the first detection signal Comp1 and the second detection signal Comp2. By directly detecting the output signal of the laser driving circuit and comparing it with the preset first threshold and second threshold, the working state during real-time monitoring can be performed, fault detection of the circuit can be performed, and abnormalities can be detected in time, thereby enhancing the reliability of the laser emitting circuit. Moreover, since only two comparators U4 and U5 are used in the laser driving circuit to determine whether the driving unit 5D and / or the laser 5A are working normally, the structure is simple, easy to implement, and low in cost.

[0087] In a specific implementation, the state judgment unit U0 may include a logic circuit subunit U6 and a timing circuit subunit U7.

[0088] In the specific circuit implementation process, considering that the supply voltage of the laser is relatively large, high-voltage devices are required. If the comparator is directly connected to the voltage HVDD of the power supply 5H and the output terminal of the drive circuit 50, the comparator is generally a low-voltage device (usually 5V) and cannot withstand the voltage of the power supply voltage HVDD (e.g., 40V).

[0089] In response to this situation, in specific implementations, the comparator is not directly connected to the power supply and the output terminal of the drive circuit. Instead, a voltage divider circuit is set up, and the voltage obtained through the voltage divider circuit can reflect the working state of the drive unit and / or the laser.

[0090] Therefore, a voltage divider unit can be provided between the output terminals of the power supply 5H and the driving unit 5D and the first comparator U4 and the second comparator U5. Specifically, the laser driving circuit 50 may further include: a first voltage divider unit U1, a second voltage divider unit U2, and a third voltage divider unit U3, wherein the first voltage divider unit U1 is coupled to the power supply 5H and the first comparator U4, the second voltage divider unit U2 is coupled to the power supply 5H and the second comparator U5, and the third voltage divider unit U3 is coupled between the output terminal of the driving unit 5H and the first comparator U4 and the second comparator U5.

[0091] In specific implementation, the input signals of the first comparator U4 and the second comparator U5 can be either voltage signals or current signals. Specifically, if the input signals of the first comparator U4 and the second comparator U5 are voltage signals, then the first comparator U4 compares the voltage signal output by the driving unit 5D with a preset first threshold voltage Vth1, and generates a corresponding first detection signal Comp1 based on the comparison result; the second comparator U5 compares the voltage signal output by the driving unit 5D with a preset second threshold voltage Vth2, and generates a corresponding second detection signal Comp2 based on the comparison result. The state judgment unit U0 then generates a corresponding operating state signal S based on the first detection signal Comp1 and the second detection signal Comp2. If the input signal is a current signal, then the first comparator and the second comparator are suitable for comparing the current signal with preset threshold currents Ith1 and Ith2 respectively, and generating a corresponding operating state signal S based on the comparison result. Of course, the input signal can also be other parameters, such as the rate of change of current or the rate of change of voltage.

[0092] In some embodiments of this specification, the input signal is a voltage signal, and the first threshold voltage Vth1 can be a value close to and slightly less than the voltage value corresponding to the highest luminous energy emitted by the laser, and the second threshold voltage Vth2 can be a value close to the lowest voltage value of the electrical energy consumed by the laser when it emits light, which is close to the safety standard for the human eye.

[0093] It should be noted that the first threshold voltage Vth1 is greater than the second threshold voltage Vth2.

[0094] The following uses a specific application of a laser as an example to illustrate the principle of detecting the operating state of the driving unit and / or the laser in the laser driving circuit as described in the embodiments of this specification:

[0095] When the channel of laser 5A is selected, and the input terminal of the corresponding driving unit 5D receives the trigger signal Tr, a light-emitting path is formed with laser 5A and energy storage unit 5B, and the entire discharge path begins to work. The voltage LDA1 (corresponding to the laser 5A) output by the driving unit 5D is divided by the third voltage divider unit U3. Figures 2 to 4The output voltage of the drive unit 5A is divided by the voltage of the first comparator 51 (V) to obtain the detection voltage Vout. This voltage is then compared with the first threshold voltage Vth1 of the first comparator U4 and the second threshold voltage Vth2 of the second comparator 52. If the detection voltage Vout is greater than the first threshold voltage Vth1, the first detection signal Comp1 output by the first comparator 51 is high (represented by the number 1), indicating that the laser 5A is open. If the detection voltage Vout is less than the second threshold voltage Vth2, the second detection signal Comp2 output by the second comparator U5 is low (represented by the number 0), indicating that the drive unit 5D is open. If the detection voltage Vout is greater than the second threshold voltage Vth2 and less than the first threshold voltage Vth1, the first detection signal Comp1 is low (represented by the number 0), and the second detection signal Comp2 is high (represented by the number 1), indicating that both the drive unit 5D and the laser 5A are in normal working condition. For ease of description, the number 1 is used to represent a high level and the number 0 is used to represent a low level.

[0096] The state judgment unit U0 can generate the corresponding operating state signal S of the driving unit 51 and / or the laser 5A based on the first detection signal Comp1 and the second detection signal Comp2.

[0097] Specifically, the first detection signal Comp1 and the second detection signal Comp2 can serve as clock signals for the logic circuit subunit U6, generating corresponding status signals that are input to the timing circuit subunit U7. The timing circuit subunit U7 can generate operating status signals suitable for characterizing the operating state of the laser and / or driving unit within the duration of a pulse input signal, such as... Figure 6 As shown, it is output to the outside, such as the upper or lower panel of the lidar or other control modules.

[0098] In practical implementation, multiple status signal output terminals can output signals that characterize the driving unit and / or laser in their respective operating states, as shown in the reference. Figure 6 and Figure 7 The operating status signal S output by the first state signal output terminal LD_Open can represent whether the laser is open-circuited, the operating status signal output by the second state signal output terminal PMOS_Open can represent whether the driving unit is open-circuited, and the operating status signal output by the third state signal output terminal Normal can represent whether both the driving unit and the laser are working normally. If the processor reads and processes the operating status signal S output by the state judgment unit U0, for example... Figure 6As shown, the operating status signal values ​​of Normal, LD_Open, and PMOS_Open can be read. If the Normal signal is 1, it is determined that neither the laser nor the drive unit is open-circuited, and both are working normally. If LD_Open is 1, it is considered that the laser is open-circuited; if PMOS_Open is 1, it is determined that the drive unit is open-circuited. This allows for error reporting to downstream devices of the lidar.

[0099] In the embodiments described in this specification, the processor can be implemented using digital logic devices, microcontrollers, central processing units (CPUs), field programmable gate arrays (FPGAs), etc.

[0100] To enable those skilled in the art to better understand and implement the embodiments of this specification, a specific implementation example of a laser driving circuit is given below. First, refer to... Figure 7 The schematic diagram of the laser driving circuit shown is provided. The laser driving circuit 70 is adapted to work with the laser 7A and the energy storage unit ( Figure 7 (Not shown) Coupled, the laser driving circuit 70 may specifically include: a driving unit 71, a first voltage divider unit U1, a second voltage divider U2, a third voltage divider unit U3, a first comparator U4, a second comparator U5, a logic circuit subunit U6, and a timing circuit subunit U7, wherein:

[0101] The driving unit 71 is adapted to conduct the energy storage unit (based on the trigger signal Tr) Figure 7 (To be shown) and the light-emitting path of laser 7A;

[0102] In the embodiments described in this specification, the driving unit can be a PMOS transistor T1, such as... Figure 7 As shown. In other embodiments of the present invention, the driving unit may also be an NMOS transistor, such as the one described in reference [reference image]. Figure 1 The driving unit is a switching transistor; any transistor that can be turned on or off is acceptable, and its specific type is not limited.

[0103] The first voltage divider unit U1 is coupled between the power supply terminal HVDD and ground GND, and is coupled to the inverting input terminal of the first comparator through the first voltage divider terminal. Specifically, the first voltage divider unit U1 may include a first resistor R1 and a second resistor R2 connected in series, and the first voltage divider terminal is disposed between the first resistor R1 and the second resistor R2;

[0104] The second voltage divider unit U2 is coupled between the power supply terminal HVDD and ground GND, and is coupled to the inverting input terminal of the second comparator through the second voltage divider terminal. Specifically, the second voltage divider unit U2 may include a third resistor R3 and a fourth resistor R4 connected in series, with the second voltage divider terminal located between the third resistor R3 and the fourth resistor R4.

[0105] The third voltage divider unit U3 is coupled between the output terminal of the drive circuit and ground, and is coupled to the non-inverting input terminals of the first comparator and the second comparator respectively through the third voltage divider terminal. Specifically, the third voltage divider unit U3 includes a fifth resistor R5 and a sixth resistor R6 connected in series, and the third voltage divider terminal is disposed between the fifth resistor R5 and the sixth resistor R6;

[0106] The first comparator U4 is adapted to compare the output signal of the drive circuit output obtained by the third voltage divider unit U3 with the first threshold obtained by the first voltage divider unit U1, and output a first detection signal Comp1 based on the comparison result. The first threshold is close to and slightly smaller than the output signal value corresponding to the laser emitting the highest luminous energy.

[0107] The second comparator U5 is adapted to compare the output signal of the drive circuit output obtained by the third voltage divider unit with the second threshold obtained by the second voltage divider unit U2, and output a second detection signal Comp2 based on the comparison result. The second threshold is less than the first threshold and slightly greater than the output signal value corresponding to the laser emitting the lowest luminous energy.

[0108] The logic circuit subunit U6 may include a latch module U61 and a logic module U62, wherein: the latch module U61 is adapted to latch the first detection signal Comp1 and the second detection signal Comp2 in the current time, and after receiving the second delay signal Tr_str2, to perform the operation of latching the first detection signal Comp1 and the second detection signal Comp2 in the next time; the logic module U62 is coupled to the latch module U61 and is adapted to output the working status signal of the driving unit and / or the laser after logical operation based on the first detection signal Comp1 and the second detection signal Comp2;

[0109] In a specific implementation, the latch module U61 may include a first D flip-flop D1 and a second D flip-flop D2. The D input terminal of the first D flip-flop D1 is coupled to the power supply terminal VDD, its clock signal input terminal is adapted to input the first detection signal Comp1 and is triggered on the rising edge, and its reset signal terminal is adapted to input the second delay signal.

[0110] The D input terminal of the second D flip-flop D2 is coupled to the power supply terminal VDD. Its clock signal input terminal is adapted to input the second detection signal Comp2 and is triggered on the rising edge. Its reset signal terminal is adapted to input the second delay signal.

[0111] The logic module U62 may include gate logic modules ( Figure 7 (not shown in the diagram), adapted to output the corresponding operating status signal of the driving unit and / or the laser to the corresponding input terminal of the timing circuit subunit U7 based on the output results of the first D flip-flop D1 and the second D flip-flop D2, including a first output terminal, a second output terminal and a third output terminal.

[0112] In some embodiments of this specification, the timing circuit subunit U7 may include a delay module U71 and a status output module U72, wherein: the delay module U71 is adapted to generate a first delay signal Tr_str1 and a second delay signal Tr_str2 based on the trigger signal Tr; the status output module U72 is adapted to latch the current operating status signal of the driving unit and / or the laser, and after receiving the first delay signal Tr_str1, perform the operation of latching the next operating status signal of the driving unit and / or the laser.

[0113] In specific implementation, we will continue to refer to Figure 7 The delay module U71 may include: a first inverter P1 and a second inverter P2, wherein: the first inverter P1 has an input terminal adapted to receive the trigger signal Tr and an output terminal adapted to output the first delay signal Tr_str1; the second inverter P2 has an input terminal adapted to receive the trigger signal Tr and an output terminal adapted to output the second delay signal Tr_str2.

[0114] It should be noted that, in order to reduce the fluctuations of the first delayed signal Tr_str1 and the second delayed signal Tr_str2, both the first inverter P1 and the second inverter P2 can be coupled with a capacitor, such as... Figure 7 As shown, the first inverter P1 is connected in parallel with the seventh capacitor C7, wherein one end of the seventh capacitor C7 is connected to the output terminal of the first inverter P1 and the other end is grounded; the second inverter P2 is coupled with the eighth capacitor C2, wherein one end of the eighth capacitor C2 is connected to the output terminal of the second inverter P1 and the other end is grounded.

[0115] The status output module U72 may include: a third D flip-flop D3, a fourth D flip-flop D4, and a fifth D flip-flop D5, wherein: the input terminal of the third D flip-flop D3 is adapted to be coupled to the first output terminal of the logic module U62, its clock signal input terminal is adapted to input the first delay signal Tr_str1, and its output terminal serves as the first status signal output terminal LD_Open, adapted to output the laser open-circuit signal LD_Open, which characterizes whether the laser is in an open-circuit state;

[0116] The input terminal of the fourth D flip-flop D4 is adapted to be coupled to the second output terminal of the logic module U62. Its clock signal input terminal is adapted to input the first delay signal Tr_str1, and its output terminal serves as the second state signal output terminal PMOS_Open, adapted to output the drive unit open circuit signal PMOS_Open that characterizes whether the drive unit is in an open circuit state.

[0117] The input terminal of the fifth D flip-flop D5 is adapted to be coupled to the third output terminal of the logic module, its clock signal input terminal is adapted to input the first delay signal Tr_str1, and its output terminal serves as the third state signal output terminal, adapted to output the signal Normal that characterizes the laser being in normal working state.

[0118] In some embodiments of the present invention, reference is made to... Figure 5 and Figure 7 The power supply voltage HVDD is divided by the first voltage divider unit U1 and the second voltage divider unit U2 to obtain the required first threshold voltage Vth1 and second threshold voltage Vth2. The output voltage LDA1 of the driving circuit is divided by the third voltage divider unit U3 to obtain the monitoring voltage Vout of the laser driving circuit 60.

[0119] Specifically, refer to Figure 7 The first threshold voltage Vth1 = R2 * HVDD / (R1 + R2), the second threshold voltage Vth2 = R4 * HVDD / (R3 + R4), and the detection voltage Vout = R6 * LDA1 / (R5 + R6).

[0120] The first comparator U4 compares the first threshold voltage Vth1 with the detection voltage Vout, and outputs a first detection signal Comp1 based on the comparison result. The second comparator U5 compares the second threshold voltage Vth2 with the detection voltage Vout, and outputs a second detection signal Comp2. Specifically, when the channel of the laser 7A starts working, the detection voltage Vout is compared with the first threshold voltage Vth1. If the detection voltage Vout is greater than the first threshold voltage Vth1, the output Comp1 is 1, indicating that the laser 7A is open-circuited. The detection voltage Vout2 is compared with the second threshold voltage Vth2. If the detection Vout2 is less than the second threshold voltage Vth2, the output Comp2 is 0, indicating that the driving unit 71 is open-circuited. If the detection Vout2 is greater than the second threshold voltage Vth2 and less than the first threshold voltage Vth1, the output Comp1 is 0 and the output Comp2 is 1, indicating that both the laser 7A and the driving unit 71 are in normal working condition. For details, please refer to [link to documentation]. Figure 6 The table showing the working status is shown.

[0121] The first detection signal Comp1 output by the first comparator U4 and the second detection signal Comp2 output by the second comparator U5 can be used as the clock signal for the logic circuit unit U6. Specifically, the first detection signal Comp1 can be used as the clock signal for the first D flip-flop D1, and the second detection signal Comp2 can be used as the clock signal for the second D flip-flop D2. The states of the first detection signal Comp1 and the second detection signal Comp2 can be latched using the first D flip-flop D1 and the second D flip-flop D2 to output the operating state signal S.

[0122] In specific implementation, if the voltage VDD at the D input terminal of the first D flip-flop D1 changes from 0 to 1, the first D flip-flop D1 is triggered on the rising edge and can latch the state of the first detection signal Comp1; otherwise, it continues to maintain the current state. Similarly, when the voltage VDD at the D input terminal of the second D flip-flop D2 changes from 0 to 1, the state of the second detection signal Comp2 can be latched.

[0123] Continue to refer to Figure 7 and combined Figure 6 The first detection signal Comp1, latched by the first D flip-flop D1, and the second detection signal Comp2, latched by the second D flip-flop D2, are processed by the logic module U62 to generate internal circuit status signals and transmit them to the timing circuit subunit U7. The status output module U72 in the timing circuit subunit U7 outputs the working status signals of the driving unit 71 and / or the laser 7A.

[0124] As a specific example, if the signal value corresponding to the first detection signal Comp1 is 1 and the signal value corresponding to the second detection signal Comp2 is 1, then the generated internal circuit status signal is sent to the third D flip-flop D3 via the first output terminal. The third D flip-flop D3 is triggered on the rising edge and outputs the working status signal as the laser open circuit signal LD_Open.

[0125] As another specific example, if the signal value corresponding to the first detection signal Comp1 is 0 and the signal value corresponding to the second detection signal Comp2 is 0, the generated internal circuit status signal is sent to the fourth D flip-flop D4 via the second output terminal. The fourth D flip-flop D4 is triggered on the rising edge and outputs the working status signal as the drive unit open signal PMOS_Open.

[0126] As another specific example, if the signal value corresponding to the first detection signal Comp1 is 0 and the signal value corresponding to the second detection signal Comp2 is 1, then the generated internal circuit status signal is sent to the fifth D flip-flop D5 via the third output terminal. The fifth D flip-flop D5 is triggered by the rising edge, and the output working status signal is a signal Normal suitable for characterizing that both the laser and the driving unit are working normally.

[0127] In a specific implementation, the clock signals of the third D flip-flop D3, the fourth D flip-flop D4, and the fifth D flip-flop D5 can be obtained by delaying and inverting the trigger signal Tr through the first inverter P1. Specifically, the clock signals at the clock signal terminals of the third D flip-flop D3, the fourth D flip-flop D4, and the fifth D flip-flop are all the trigger signal Tr, which is delayed and inverted by the first inverter P1 to form a first delayed signal Tr_str1.

[0128] After completing the above process, in order to facilitate the monitoring of the next operating status signal of the driving unit and / or the laser, in specific implementation, it is necessary to reset the first D flip-flop D1 and the second D flip-flop D2. Specifically, the second delayed signal Tr_str2 obtained by delaying and inverting the trigger signal Tr through the second inverter P2 can be used as the reset signal for the first D flip-flop D1 and the second D flip-flop D2, and input to the reset signal terminal R.

[0129] The solution described in this specification can be applied to the field of pulse ranging lidar. Due to the inherent characteristics, power consumption, and reliability issues of lidar, continuous emission of DC input signals is not suitable; most lidars use pulse signals for ranging. Monitoring DC input signals is relatively easy to implement, requiring only a simple threshold comparison, and the comparison value will remain constant. However, pulse input signals place higher demands on the detection circuit, requiring not only that the threshold comparison be completed within a specified time, but also that the comparison output signal be maintained until a fault is resolved. To address these challenges, this specification utilizes the input pulse trigger signal Tr to generate a corresponding delayed inverse timing signal. Furthermore, using logic circuitry (a first-stage flip-flop), after monitoring the operating status signal of the driving unit and / or the laser, the current trigger signal Tr needs to be inverted before receiving the next trigger signal Tr, resulting in a first delayed signal Tr_str1 and a second delayed signal Tr_str2. In other words, the duration of the first delay signal Tr_str1 and the second delay signal Tr_str2 relative to the current trigger signal Tr is less than the time interval between two consecutive adjacent trigger signals Tr, that is, the time interval between two consecutive adjacent trigger pulses. In addition, in specific implementations, the time interval between two consecutive adjacent trigger pulses can be set to the interval encoding value of two consecutive adjacent pulses.

[0130] Furthermore, in order to simultaneously satisfy the requirements of the first and second comparators completing the comparison operation and the state judgment unit completing the logic operation, the first delay signal Tr_str1 and the second delay signal Tr_str2 also need to meet certain requirements. Since the second delay signal Tr_str2 only takes effect when the next trigger signal is received, while the first delay signal Tr_str1 takes effect when the current trigger signal is received, the duration of the first delay signal Tr_str1 can be set to be less than the duration of the second delay signal Tr_str2. That is, ensure that the rising edge of the second delay signal Tr_str2 is after the rising edge of the first delay signal Tr_str1, determine that the pulse comparison state corresponding to the current trigger signal is retained, and then reset the first D flip-flop D1 and the second D flip-flop D2.

[0131] By setting the duration of the second delay signal to be greater than the duration of the first delay signal and less than the time interval between two consecutive adjacent trigger signals, it can be ensured that each device meets the timing requirements. This ensures that the working status signal output of the driving unit and / or laser corresponding to the current trigger signal is completed before the next trigger signal arrives, thereby realizing the monitoring of the driving circuit used for pulse ranging.

[0132] This specification also provides another specific implementation example of a laser driver circuit, such as... Figure 8The laser driver circuit 80 shown is, with Figure 7 The difference between the laser driving circuit 70 shown is that the first voltage divider unit U1, the second voltage divider unit U2, and the third voltage divider unit U3 of the laser driving circuit 80 are all composed of capacitors.

[0133] Specifically, the first voltage divider unit U1 includes a first capacitor C1 and a second capacitor C2 connected in series, and the first voltage divider terminal is disposed between the first capacitor C1 and the second capacitor C2.

[0134] The second voltage divider unit U2 includes a third capacitor C3 and a fourth capacitor C4 connected in series, and the second voltage divider terminal is disposed between the third capacitor C3 and the fourth capacitor C4;

[0135] The third voltage divider unit U3 includes a fifth capacitor C5 and a sixth capacitor C6 connected in series, and the third voltage divider terminal is located between the fifth capacitor C5 and the sixth capacitor C6.

[0136] To enable those skilled in the art to better understand the concept, advantages, and implementation schemes of the solutions provided in this specification, the following uses waveform diagrams under different operating state signals to illustrate the voltage changes of key nodes in the circuits of the embodiments in this specification.

[0137] Case 1: Neither the drive unit nor the laser is open-circuited, meaning the output working status signal is Normal, which indicates that both the drive unit and the laser are in normal working condition.

[0138] Reference Figure 9 The diagram shows the waveforms of the drive unit trigger signal and the output voltage signal of the drive circuit. Waveform 9A represents the waveform of the drive unit trigger signal voltage, and waveform 9B represents the waveform of the output voltage LDA1 of the drive circuit. Figure 9 It can be seen that within 0 to 1 μs, when the driving circuit does not receive the trigger signal Tr, the trigger signal voltage of the driving unit is zero, and the output voltage LDA1 is zero. Starting at 1 μs, when multiple trigger signals Tr are continuously input, the output voltage LDA1 of the driving circuit begins to change with a voltage drop following the trigger signal Tr.

[0139] Reference Figure 10 The diagram shows the voltage waveforms at corresponding monitoring points in the laser driver circuit. (From...) Figure 10It can be seen that starting from the 1 μs moment, multiple trigger signals Tr are continuously input. Since the first threshold voltage Vth1 obtained by the power supply voltage through the first voltage dividing unit is always greater than the detected Vout, the output value of Comp1 is always 0 (low level); since the detected voltage Vout is pulse-shaped, only when the second threshold voltage Vth2 obtained by the power supply voltage through the second voltage dividing unit is less than the detected voltage Vout, the output of Comp2 is 1 (high level). Therefore, Figure 10 the voltage waveform of Comp2 in

[0140] is a small spike corresponding to multiple pulses. Figure 11 Referring to the timing diagram of the laser driver circuit shown in Figure 7 , the output of the timing circuit subunit is controlled by the first delay signal Tr_str1. Among them, the output working state signal Normal is at a high level, that is, both the laser and the driving unit are working normally. The second delay signal Tr_str2 is used to reset the first D flip-flop D1 and the second D flip-flop D2 to facilitate the monitoring of the next trigger signal.

[0141] To achieve continuous monitoring of continuous multi-pulse trigger signals, in a specific implementation, the durations of the first delay signal Tr_str1, the second delay signal Tr_str2, and the trigger signal Tr can be set to satisfy a preset relationship.

[0142] In some embodiments of this specification, as Figure 11 shown, the duration t1 of the first delay signal Tr_str1 is less than the duration t2 of the second delay signal Tr_str2, that is, t1 < t2; the duration t1 of the first delay signal Tr_str1 is less than the time interval t3 between two consecutive adjacent trigger signals Tr, that is, t1 < t3; the duration of the second delay signal Tr_str2 is less than the time interval between two consecutive adjacent trigger signals Tr, that is, t2 < t3. From the above, it can be seen that the overall durations of the pulses corresponding to the first delay signal Tr_str1, the second delay signal Tr_str2, and the trigger signal Tr are t1 < t2 < t3.

[0143] Case 2: The laser is open, that is, the working state signal output by the state output module is LD_Open.

[0144] Referring to Figure 12 the waveform diagram of the trigger signal voltage of the driving unit and the voltage LDA1 at the output end of the laser driver circuit shown in Figure 12It can be seen that starting at 1μs, the trigger signal receiver of the driving unit begins to receive continuous transmission pulse signals, and the voltage signal LDA1 at the output of the laser driving circuit also begins to drop following the trigger signal Tr. At 2μs, the laser LD is open-circuited, and the voltage signal LDA1 at the short-circuited output of the laser driver increases, approaching the power supply voltage signal HVDD. The voltage of the trigger signal Tr of the driving unit remains unchanged. Figure 12 As shown.

[0145] Reference Figure 13 The diagram shows the voltage waveforms at each monitoring point of the laser driver circuit. The inputs of both the first and second comparators receive the voltage divider signal Vout corresponding to the output voltage signal LDA1 of the laser driver circuit. Figure 13 It can be seen that starting from 1μs, based on the continuous emission pulse signal received by the driving unit, the voltage signal LDA1 at the output of the laser driving circuit also begins to drop along with the trigger signal Tr, and the laser works normally. After 2μs, the PMOS of the driving unit is open, and the voltage Vth1 obtained by the power supply voltage through the first voltage divider unit is always less than Vout1, so the output of comparator Comp1 is always 1 (high level); the voltage Vth2 obtained by the power supply voltage through the second voltage divider unit is always less than the voltage divider signal Vout2 at the output of the laser driving circuit, and the output of comparator Comp2 is always 1 (high level).

[0146] Reference Figure 14 The waveform diagram of the laser driver circuit shown is combined with... Figure 7 During the 1μs to 2μs period, the laser LD emits light accordingly based on the trigger signal Tr. Therefore, the normal output of the working status signal is high (corresponding to an output value of 1), that is, both the driving unit and the laser are working normally. Starting at 2μs, an open circuit fault occurs in the laser. In addition, under the control of the first delay signal Tr_str1, the output signal LD_Open of the working status signal terminal is high, and the output signal Normal of the working status signal terminal becomes low. The second delay signal Tr_str2 is used to reset the first D flip-flop D1 and the second D flip-flop D2, so as to continue monitoring the next trigger signal.

[0147] In specific implementation, such as Figure 14As shown, the duration t4 of the first delay signal Tr_str1 is less than the duration t5 of the second delay signal Tr_str2, i.e., t4 < t5; the duration t4 of the first delay signal Tr_str1 is less than the time interval t6 between two consecutive adjacent trigger signals Tr, i.e., t4 < t6; the duration t5 of the second delay signal Tr_str2 is less than the time interval t6 between two consecutive adjacent trigger signals Tr, i.e., t5 < t6. In summary, the durations of the first delay signal Tr_str1, the second delay signal Tr_str2, and the trigger signal Tr satisfy the following relationship: t4 < t5 < t6.

[0148] Case 3: The drive unit is open, that is, the working state signal output by the state output module is PMOS_Open.

[0149] Refer to Figure 15 the waveform diagram of the drive circuit trigger signal voltage and the output voltage LDA1 shown, where waveform 15A represents the waveform of the drive circuit trigger signal Tr voltage, and waveform 15B is the waveform of the voltage LDA1 at the output end of the laser drive circuit. From Figure 15 it can be seen that starting from the 2 μs moment, a pulse signal of multiple consecutive trigger signals Tr is emitted, and the drive unit PMOS is open. At this time, the voltage at the output end of the drive circuit is close to zero.

[0150] Refer to the voltage waveform diagram of the corresponding monitoring points of the laser drive circuit as shown in 16. After the 2 μs moment, the drive unit PMOS is open, and the voltage signal LDA1 at the output end of the drive circuit is zero. Correspondingly, the detected voltage signal Vout is zero. Therefore, the first threshold voltage Vth1 obtained by the power supply voltage HVDD through the first voltage dividing unit is always greater than the detected voltage Vout. Thus, the output value of the first comparator Comp1 is always 0 (corresponding to a low level); the second threshold voltage Vth2 obtained by the power supply voltage HVDD through the second voltage dividing unit is always greater than the detected voltage signal Vout, and the output value of the second comparator Comp2 is always 0 (corresponding to a high level).

[0151] Refer to Figure 17 the timing diagram of the laser drive circuit shown, and combined with Figure 7 , the timing circuit sub-unit is controlled by the first delay signal. Starting from the 2 μs moment, the PMOS_Open signal output by the working state signal terminal becomes high level (corresponding to a signal value of 1), and the Normal signal of the working state signal terminal becomes low level (corresponding to a signal value of 0). The second delay signal Tr_str2 is used to reset the first D flip-flop D1 and the second D flip-flop D2 to facilitate the monitoring of the next trigger signal.

[0152] In a specific implementation, continue to refer to Figure 17 The duration t7 of the first delay signal Tr_str1 is less than the duration t8 of the second delay signal Tr_str2, that is, t7 < t8; the duration t7 of the first delay signal Tr_str1 is less than the time interval t9 between two consecutive trigger signals Tr, that is, t7 < t9; the duration t8 of the second delay signal Tr_str2 is less than the time interval t9 between two consecutive trigger signals Tr, that is, t8 < t9. In summary, the durations of the first delay signal Tr_str1, the second delay signal Tr_str2, and the trigger signal satisfy the following relationship: t7 < t8 < t9.

[0153] The laser driver circuits in the above embodiments can be applied to a transmitting device. More specifically, the transmitting device including the laser driver circuit can be applied to a lidar. To enable those skilled in the art to better understand and implement the embodiments of the present invention, the corresponding transmitting device and lidar will be described in detail below with reference to the accompanying drawings through specific embodiments.

[0154] Refer to Figure 18 Regarding the described transmitting device, the transmitting device 180 may include: a laser 181, an energy storage unit 182, and a driver circuit 183, where:

[0155] The driver circuit 183 can be coupled to a power supply HVDD, the laser 181, the energy storage unit 182, and a controller 18A. Among them, the driver circuit 183 may include: a driving unit 1831, a first comparator 1832, a second comparator 1833, and a state determination unit 1834. The driver circuit may specifically adopt the laser driver circuit described in any of the foregoing embodiments to drive the laser to emit light based on a trigger signal, and output a working state signal of the driving unit 1831 and / or the laser 181 to the controller 18A to perform corresponding fault protection operations when it is determined that the driver circuit 183 and / or the laser 181 is in a fault state; the specific structure, working principle, advantages, etc. can all be referred to the foregoing embodiments and will not be elaborated here.

[0156] The energy storage unit 182 is coupled to the laser 181, and is adapted to form a charging path with the power supply and a light emission path (or a discharge path) with the laser 181; and, the energy storage unit 182 is adapted to be charged via the charging path when the driving unit is turned off, and to discharge via the light emission path when the driving unit is turned on, so that the laser 181 emits light pulses.

[0157] The embodiments of this specification also provide a corresponding lidar. Refer to Figure 19The schematic diagram of the lidar structure shown indicates that the lidar 190 may specifically include: a light emitting device 191, a driving device 192, an energy storage device 193, and a controller 194, wherein:

[0158] The light emitting device 191 includes a plurality of lasers 1911;

[0159] The driving device 192 includes multiple driving circuits 1921, each driving circuit 1921 being coupled to the energy storage device 193, the controller 194, and a corresponding laser 194. Each driving circuit 1921 may include a driving unit 19211, a first comparator 19212, a second comparator 19213, and a status judgment unit 19214. Each driving circuit 1921 may specifically adopt the laser emission driving circuit described in any of the foregoing embodiments, driving the corresponding laser 1911 to emit light based on a trigger signal, and outputting the corresponding driving unit 19211 and / or the laser 1911's operating status signal to the controller 194, so as to perform corresponding fault protection operations when it is determined that the corresponding driving circuit 1921 is in a fault state.

[0160] Energy storage device 193 includes energy storage unit 1931, which is coupled to at least one of the lasers 1911, and is adapted to form a charging path with power supply HVDD and a light emission path with the coupled lasers. The energy storage unit 1931 is adapted to be charged through the charging path when the coupled driving unit 19211 is turned off, and to be discharged through the light emission path when the coupled driving unit 19211 is turned on, so that the coupled lasers emit light pulses.

[0161] The controller 194 is adapted to be coupled to one or more of the driving devices 192, and is adapted to output a trigger signal to the driving unit 19211 of the corresponding driving circuit 1921 based on preset emission control parameters to drive the corresponding laser 1911 to emit light. Based on the received operating status signals of the driving unit 19211 and / or the laser 1911, when it is determined that the driving circuit 1921 and / or the laser 1911 is in a fault state, the controller 194 performs a corresponding fault protection operation.

[0162] In practical implementation, the transmitting device described in the embodiments of this specification can be used in each transmitting channel of the lidar. For multi-line scanning lidar, the above-mentioned laser driving circuit and laser can be used in each channel to achieve laser scanning and obtain point cloud data.

[0163] When using the lidar in the embodiments of this specification for ranging and other tasks, if there is an open circuit fault in the laser or drive unit of any channel, it can be detected in real time, and corresponding fault protection operations can be performed.

[0164] In a specific implementation, the energy storage device 193 may include one or more energy storage units 1931, which can continuously supply power to a laser through multiple energy storage units, thereby enabling the continuous emission of multiple laser pulses.

[0165] As can be seen from the above, when an open-circuit fault occurs in the laser or drive unit using the lidar in the embodiments of this specification, it can be detected in time, and then corresponding fault protection operations can be carried out, thereby improving the reliability and detection performance of the lidar.

[0166] In specific implementation, we will continue to refer to Figure 19 The controller 194 is adapted to output a transmission control signal to control the corresponding transmission channel to stop working when it determines that the laser 1911 is open or / and the drive unit 19211 is open based on the received operating status signals of the drive unit 19211 and / or the laser 1911.

[0167] In some embodiments of this specification, the controller 194 is also adapted to output a corresponding open-circuit alarm signal when it determines that the laser 1911 is open or / and the drive circuit 1921 is open based on the received operating status signals of the drive unit 19211 and / or the laser 1911.

[0168] It should be noted that, for the sake of simplicity, Figure 19 Each component is shown as a single example; in actual implementations, each component may contain one or more. The above examples are for illustrative purposes only and do not limit the actual structure of applicable lidar systems.

[0169] While the embodiments of the present invention have been disclosed above, the present invention is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A laser driving circuit, coupled to an energy storage unit and a laser, characterized in that, The laser driving circuit includes: A driving unit is adapted to activate the light-emitting path including the energy storage unit and the laser based on a trigger signal; A first comparator is adapted to compare the output signal of the laser driving circuit with a first threshold, and output a first detection signal based on the comparison result. The first threshold is close to and slightly smaller than the output signal value corresponding to the laser emitting the highest luminous energy. The second comparator is adapted to compare the output signal of the laser driving circuit with a second threshold, and output a second detection signal based on the comparison result. The second threshold is less than the first threshold and slightly greater than the output signal value corresponding to the laser emitting the lowest luminous energy. A state determination unit is adapted to output the operating state signal of the driving unit and / or the laser based on the first detection signal and the second detection signal. The state determination unit includes a logic circuit subunit, which includes a latch module and a logic module. The latch module is adapted to latch the first detection signal and the second detection signal in the current time, and after receiving the second delay signal, to perform the operation of latching the first detection signal and the second detection signal in the next time. The second delay signal is generated based on the trigger signal after a delay. The logic module is coupled to the latch module and is adapted to output the operating state signal of the driving unit and / or the laser after logical operation based on the first detection signal and the second detection signal.

2. The laser driving circuit according to claim 1, characterized in that, The state determination unit further includes a timing circuit subunit, which includes a delay module and a state output module, wherein: the delay module is adapted to generate a first delay signal and a second delay signal after delaying the trigger signal; the state output module is adapted to latch the current operating state signal of the driving unit and / or the laser, and after receiving the first delay signal, perform the operation of latching the next operating state signal of the driving unit and / or the laser.

3. The laser driving circuit according to claim 2, characterized in that, The duration of the second delay signal is greater than the duration of the first delay signal, but less than the time interval between two consecutive trigger signals.

4. The laser driving circuit according to claim 2, characterized in that, The latch module includes: a first D flip-flop and a second D flip-flop; the logic module includes a gate logic circuit module, wherein: The first D flip-flop has its D input terminal coupled to the power supply terminal, its clock signal input terminal adapted to input the first detection signal and is triggered on the rising edge, and its reset signal terminal adapted to input the second delay signal; The second D flip-flop has its D input terminal coupled to the power supply terminal, its clock signal input terminal adapted to input the second detection signal and is triggered on the rising edge, and its reset signal terminal adapted to input the second delay signal; The gate logic circuit module is adapted to output the corresponding operating status signal of the driving unit and / or the laser to the corresponding input terminal of the timing circuit subunit based on the output results of the first D flip-flop and the second D flip-flop, including a first output terminal, a second output terminal and a third output terminal.

5. The laser driving circuit according to claim 4, characterized in that, The delay module includes: a first inverter and a second inverter, wherein: The first inverter has an input terminal adapted to receive the trigger signal and an output terminal adapted to output the first delay signal. The second inverter has its input terminal adapted to receive the trigger signal and its output terminal adapted to output the second delay signal; The status output module includes: a third D flip-flop, a fourth D flip-flop, and a fifth D flip-flop, wherein: The third D flip-flop has an input terminal adapted to be coupled to the first output terminal of the gate logic circuit, a clock signal input terminal adapted to input the first delay signal, and an output terminal adapted to output a laser open-circuit signal characterizing that the laser is in an open-circuit state. The fourth D flip-flop has an input terminal adapted to be coupled to the second output terminal of the gate logic circuit, a clock signal input terminal adapted to input the first delay signal, and an output terminal adapted to output a driving unit open circuit signal that indicates that the driving unit is in an open circuit state. The fifth D flip-flop has its input terminal adapted to be coupled to the third output terminal of the gate logic circuit, its clock signal input terminal adapted to input the first delay signal, and its output terminal adapted to output a signal characterizing that the laser is in normal working state.

6. The laser driving circuit according to any one of claims 1-5, characterized in that, Also includes: The first voltage divider unit, the second voltage divider unit, and the third voltage divider unit, wherein: The first voltage divider unit is coupled between the power supply and ground, and is coupled to the inverting input terminal of the first comparator through the first voltage divider terminal; The second voltage divider unit is coupled between the power supply and ground, and is coupled to the inverting input terminal of the second comparator through the second voltage divider terminal; The third voltage divider unit is coupled between the output terminal of the laser driver circuit and ground, and is coupled to the non-inverting input terminal of the first comparator and the non-inverting input terminal of the second comparator respectively through the third voltage divider terminal.

7. The laser driving circuit according to claim 6, characterized in that, The first voltage divider unit includes a first resistor and a second resistor connected in series, and the first voltage divider terminal is disposed between the first resistor and the second resistor; The second voltage divider unit includes a third resistor and a fourth resistor connected in series, and the second voltage divider terminal is disposed between the third resistor and the fourth resistor; The third voltage divider unit includes a fifth resistor and a sixth resistor connected in series, and the third voltage divider terminal is disposed between the fifth resistor and the sixth resistor.

8. The laser driving circuit according to claim 6, characterized in that, The first voltage divider unit includes a first capacitor and a second capacitor connected in series, and the first voltage divider terminal is disposed between the first capacitor and the second capacitor; The second voltage divider unit includes a third capacitor and a fourth capacitor connected in series, and the second voltage divider terminal is disposed between the third capacitor and the fourth capacitor; The third voltage divider unit includes a fifth capacitor and a sixth capacitor connected in series, and the third voltage divider terminal is disposed between the fifth capacitor and the sixth capacitor.

9. A launching device, characterized in that, include: Laser; The laser driving circuit according to any one of claims 1-8, coupled to a power supply, the laser, the energy storage unit, and a controller, includes: a driving unit, a first comparator, a second comparator, and a status determination unit. The laser driving circuit is adapted to drive the laser to emit light based on a trigger signal and output the operating status signal of the driving unit and / or the laser to the controller, so as to perform corresponding fault protection operations when it is determined that the driving unit and / or the laser is in a fault state. The energy storage unit is coupled to the laser and is adapted to form a charging path with the power supply and a light-emitting path with the laser; and the energy storage unit is adapted to be charged by the power supply through the charging path when the driving unit is turned off, and to be discharged through the light-emitting path when the driving unit is turned on, so that the laser emits light pulses.

10. A lidar, characterized in that, include: The device comprises an optical emitting device, a driving device, an energy storage device, and a controller, wherein: The light emitting device includes multiple lasers; The driving device includes multiple driving circuits, each driving circuit being coupled to the energy storage device, the controller, and a corresponding laser. Each driving circuit includes a driving unit, a first comparator, a second comparator, and a status judgment unit. Specifically, it adopts the laser driving circuit described in any one of claims 1-8, drives the corresponding laser to emit light based on a trigger signal, and outputs the corresponding driving unit and / or the laser's operating status signal to the controller, so as to perform corresponding fault protection operations when it is determined that the corresponding driving circuit is in a fault state. An energy storage device includes an energy storage unit coupled to at least one of the lasers, adapted to form a charging path with a power source and a light emission path with the coupled lasers, wherein the energy storage unit is adapted to charge via the power source through the charging path when the coupled driving unit is turned off, and to discharge via the light emission path when the coupled driving unit is turned on, so that the coupled lasers emit light pulses. The controller is adapted to be coupled to the driving device, and is adapted to output a trigger signal to the driving unit of the corresponding driving circuit based on preset emission control parameters to drive the corresponding laser to emit light. Based on the received operating status signal of the driving unit and / or the laser, when it is determined that the driving circuit and / or the laser is in a fault state, the controller performs the corresponding fault protection operation.

11. The lidar according to claim 10, characterized in that, The controller is adapted to output a transmission control signal to control the corresponding transmission channel to stop working when it determines that the laser is open or / and the driving unit is open based on the received operating status signal of the driving unit and / or the laser.

12. The lidar according to claim 10, characterized in that, The controller is also adapted to output a corresponding open-circuit alarm signal when it determines that the laser is open or / and the drive circuit is open based on the received operating status signals of the drive unit and / or the laser.

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