Drive circuit, heating device, lidar for lidar window heating

Abstract

A kind of drive circuit for laser radar window heating, heating device, laser radar, drive circuit shares power supply with other functional modules of laser radar, and drive circuit includes: heating unit, current control module and switching module;Heating unit is connected with power supply, and current control module and switching module are connected with heating unit respectively;Switching module is configured to switch heating unit between first heating mode and second heating mode based on the working state of functional module of shared power supply, and the heating power of first heating mode and second heating mode is different;Current control module is used to adjust the current in drive circuit in first heating mode.The present application scheme improves the heating power of heating unit, while ensuring that total load current will not exceed rated current.

Description

Technical Field

[0001] This invention relates to the field of circuit technology, specifically to a driving circuit for heating a lidar window, and also to a heating device and a lidar. Background Technology

[0002] LiDAR (LiDAR) is a radar system that uses laser beams to detect the position, velocity, and other characteristics of targets. When lidar operates in low ambient temperatures, frost can form on its surface, affecting its detection capabilities. To address this, heating units are typically installed on the lidar's photomask to defrost and remove this frost. Common heating units are driven by a DC power supply based on their resistance and the desired heating power. Because the resistance of heating units increases significantly with age, to ensure effective heating over long-term use, a relatively low initial resistance and a higher voltage are usually chosen for their operation.

[0003] In current LiDAR products, the laser and heating circuit mostly share a power supply, which increases the total load current when the laser is operating. Similarly, besides the laser, when the heating unit shares a power supply with other modules (such as the detector), it also causes an increase in the total load current. Therefore, it is impossible to increase the heating power of the heating unit while ensuring that the total load current does not exceed the rated current. Summary of the Invention

[0004] This application provides a driving circuit, heating device, and lidar for heating the window of a lidar, which improves the heating power of the heating unit while ensuring that the total load current does not exceed the rated current.

[0005] Therefore, the embodiments of the present invention provide the following technical solutions:

[0006] On one hand, embodiments of the present invention provide a driving circuit for heating a lidar window. The driving circuit shares a power supply with other functional modules of the lidar. The circuit includes: a heating unit, a current control module, and a switching module. The heating unit is connected to the power supply, and the current control module and the switching module are respectively connected to the heating unit.

[0007] The switching module is configured to switch the heating unit between a first heating mode and a second heating mode based on the working state of the functional module that shares the power supply. The heating power of the first heating mode and the second heating mode are different.

[0008] The current control module is used to adjust the current in the drive circuit under the first heating mode.

[0009] Optionally, the current control module includes: a first switch and a first control unit; the first control unit is used to control the opening and closing of the first switch.

[0010] Optionally, the first control unit is further configured to adjust the on-resistance of the first switch when the first switch is turned on.

[0011] Optionally, the first control unit inputs a first digital signal and outputs a first control signal to the first switch.

[0012] Optionally, the first control unit includes a digital-to-analog converter, which outputs a first control signal and controls the first switch to be turned on or off or adjusts the on-resistance of the first switch by adjusting the magnitude of the first control signal.

[0013] Optionally, the first control unit further includes: a first resistor and a buffer; the first resistor is connected in series with the first switch; the positive input terminal of the buffer is connected to the output terminal of the digital-to-analog converter, the output terminal of the buffer is connected to the control terminal of the first switch, and the negative input terminal of the buffer is connected to the output terminal of the first switch; the first resistor and the buffer form a feedback loop, and the feedback loop controls the on-resistance of the first switch to reach a preset value.

[0014] Optionally, the first switch includes a first NMOS transistor; the first control signal is input to the gate of the first NMOS transistor.

[0015] Optionally, the first switch includes a first NPN transistor; the first control signal is input to the base of the first NPN transistor.

[0016] Optionally, the switching module includes: a judgment unit and a switching control unit;

[0017] The judgment unit is used to generate a second control signal based on the first control signal and the first enable signal; the first enable signal is mutually exclusive with the enable signal of the functional module that shares the power supply with the heating unit.

[0018] The switching control unit is used to control the heating unit to switch between a first heating mode and a second heating mode according to the second control signal.

[0019] Optionally, the determination unit is an AND gate.

[0020] Optionally, the switching control unit includes a second NMOS transistor; the second control signal is input to the gate of the second NMOS transistor.

[0021] Optionally, the switching control unit includes: a second NPN transistor; the second control signal is input to the base of the NPN transistor.

[0022] Optionally, the switching control unit includes: a gating switch; and the second control signal is input to the control terminal of the gating switch.

[0023] Optionally, the circuit further includes a current sampling module for acquiring the current in the drive circuit.

[0024] Optionally, the pulse width of the first control signal is dynamically adjusted according to the current collected by the current sampling module, so that the heating power of the heating unit in the first heating mode reaches the rated power.

[0025] Optionally, the circuit further includes a monitoring module for monitoring the current collected by the current sampling module and determining whether there is a short circuit or open circuit in the heating unit branch based on the current.

[0026] Optionally, the heating unit is an ITO film.

[0027] On the other hand, embodiments of the present invention also provide a heating device, which includes the driving circuit described above.

[0028] On the other hand, embodiments of the present invention also provide a lidar, which includes a laser and the heating device described above, wherein the heating device and the laser share a power supply.

[0029] The driving circuit, heating device, and lidar for heating the lidar window provided in this embodiment of the invention adopt a structure design in which the driving circuit and other functional modules of the lidar share a power supply. This eliminates the need to change the existing structure of multiple modules sharing the same power supply in lidar. By using a switching module control, the heating unit can use different heating powers according to the working state of the functional modules sharing the power supply. This allows for increased heating power while ensuring that the total load current does not exceed the rated current. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of a circuit structure where the laser and the ITO film heating circuit share a power supply.

[0031] Figure 2 This is a schematic block diagram of the driving circuit for heating the lidar window according to an embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of a drive circuit for heating a lidar window according to an embodiment of the present invention;

[0033] Figure 4This is a schematic diagram of a specific implementation circuit of the driving circuit for heating the lidar window in an embodiment of the present invention;

[0034] Figure 5 This is a schematic diagram of another specific implementation circuit of the driving circuit for heating the lidar window in an embodiment of the present invention;

[0035] Figure 6 yes Figure 5 A schematic diagram of a modified structure of the driving circuit shown;

[0036] Figure 7 This is a schematic diagram of another specific implementation circuit of the driving circuit for heating the lidar window in an embodiment of the present invention;

[0037] Figure 8 yes Figure 7 A schematic diagram of a modified structure of the driving circuit shown;

[0038] Figure 9 This is a schematic diagram of another specific implementation circuit of the driving circuit for heating the lidar window in an embodiment of the present invention;

[0039] Figure 10 This is a schematic diagram of another specific implementation of the driving circuit for heating the lidar window in an embodiment of the present invention. Detailed Implementation

[0040] To make the above-mentioned objectives, features and beneficial effects of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0041] like Figure 1 As shown, laser 10 and heating circuit 20 share the same power supply HV. When laser 10 is not working, the total load current is only the current of the heating circuit 20 branch. When laser 10 is working, the total load current is the sum of the current of the heating circuit 20 branch and the current of the laser 10 branch. Therefore, the total load current increases when the laser is working. Similarly, besides the laser, when the heating circuit shares the power supply with other modules (such as the detector), it will also cause the total load current to increase. Figure 1The heating circuit power supply scheme shown cannot simultaneously meet the requirements of both heating power and ensuring that the load current does not exceed the rated current. Specifically, to guarantee the heating power of the heating unit after aging, heating units with smaller initial resistance are typically used. Therefore, the current in the heating circuit is relatively high before the heating unit ages. If the heating power is further increased, the total load current in the circuit will exceed the rated current when the laser is operating, causing circuit safety issues. Conversely, if a heating unit with a larger initial resistance is selected, the heating power will be too low after aging to meet the requirements. To address the problems in existing power supply structures where the laser and heating circuit share a power supply, this invention provides a driving circuit for heating the window of a lidar. This driving circuit shares a power supply with other functional modules of the lidar. A switching module controls the heating unit to use different heating powers according to the operating state of the functional modules sharing the power supply, thereby increasing the heating power while ensuring that the total load current does not exceed the rated current.

[0042] like Figure 2 The diagram shown is a schematic block diagram of the driving circuit for heating the lidar window according to an embodiment of the present invention.

[0043] The drive circuit for heating the lidar window shares a power supply 100 with other functional modules of the lidar. The drive circuit includes a heating unit 101, a current control module 102, and a switching module 103. The heating unit 101 is connected to the power supply 100, and the current control module 102 and the switching module 103 are respectively connected to the heating unit 101.

[0044] In this embodiment, the switching module 103 is configured to switch the heating unit 101 between a first heating mode and a second heating mode based on the operating state of the functional modules of the shared power supply 100. The heating power of the first heating mode and the second heating mode are different. Correspondingly, the current control module 102 is used to adjust the current in the drive circuit in the first heating mode.

[0045] In this solution, the heating mode of the heating unit 101 is switched by the working state of the shared power supply module. When the shared power supply module is not working, the heating unit 101 uses a higher heating power, and when the shared power supply module is working, the heating unit 101 uses a lower heating power. This ensures that the total load current does not exceed the rated current while increasing the heating power of the heating unit 101.

[0046] like Figure 3 The diagram shown is a schematic representation of a drive circuit for heating a lidar window according to an embodiment of the present invention.

[0047] In this embodiment, the current control module 102 includes a first switch 121 and a first control unit 122, and the switching module 103 includes a judgment unit 131 and a switching control unit 132.

[0048] The first control unit 122 controls the on and off states of the first switch 121. Furthermore, when the first switch 121 is on, the first control unit 122 can adjust the on-resistance of the first switch 121, thereby controlling or adjusting the current in the branch where the current control module 102 is located, and thus controlling or adjusting the heating power of the heating unit 101. For example, the current control module 102 can maintain a constant current in its branch, thereby controlling the heating power of the heating unit 101. Alternatively, the current control module 102 can change the current level in its branch, thereby adjusting the heating power of the heating unit 101.

[0049] Specifically, the first control unit 122 inputs a first digital signal and outputs a first control signal to the first switch 121, thereby achieving the above-mentioned adjustment and control of the first switch 121 through the first control signal.

[0050] The judgment unit 131 is used to generate a second control signal based on the first control signal and the first enable signal; the switching control unit 132 controls the heating unit 101 to switch between a first heating mode and a second heating mode based on the second control signal. The first enable signal indicates the operating state of the functional module that shares a power supply with the heating unit 101, and is mutually exclusive with the enable signal of the functional module sharing the power supply; the enable signal of the functional module sharing the power supply is the conduction signal of the functional module. Specifically, refer to... Figure 3 As shown, the first control signal and the first enable signal are input to the judgment unit 131. The judgment unit generates a second enable signal based on the first control signal and the first enable signal, and outputs the second enable signal to the switching control unit 132.

[0051] It should be noted that the first enable signal is mutually exclusive with the enable signal of the functional module that shares the power supply with the heating unit 101. That is, when the enable signal of the functional module is a conducting signal (e.g., high level), the first enable signal is a de-conducting signal (e.g., low level), and when the enable signal of the functional module is a de-conducting signal (e.g., low level), the first enable signal is a conducting signal (e.g., high level). For example, when the heating unit 101 and the laser share the power supply 100, the laser is the aforementioned functional module, and the enable signal of the functional module is the conduction control signal of the laser. When the laser needs to emit light, it is enabled, and the first enable signal is a de-conducting signal; when the laser does not need to emit light, it is not enabled, and the first enable signal is a conducting signal. The first enable signal can reflect the working status of the functional module (laser) that shares the power supply with the heating unit 101. Therefore, when the heating unit 101 needs to work (the first control signal is high level) and the functional module that shares the power supply with the heating unit 101 is not enabled (the first enable signal is high level), the judgment unit outputs the second control signal and switches the control unit 132 to the second heating mode with higher power.

[0052] In practical applications, the first switch 121 can be implemented by a MOSFET or a transistor, and the switching control unit 132 can be implemented by a MOSFET, a transistor, or a selector switch.

[0053] The driving circuit for heating the lidar window provided in this embodiment of the invention adopts a structure design in which the driving circuit shares a power supply with other functional modules of the lidar. This eliminates the need to change the existing structure of multiple modules sharing the same power supply in lidar. By using a switching module control, the heating unit can use different heating powers according to the working state of the functional modules sharing the power supply. This allows for increased heating power while ensuring that the total load current does not exceed the rated current.

[0054] The following example illustrates the specific implementation circuit of the driving circuit for heating the lidar window in an embodiment of the present invention.

[0055] Reference Figure 4 The diagram shown is a schematic representation of a specific implementation circuit for a laser radar window heating drive circuit according to an embodiment of the present invention.

[0056] At the same time, in conjunction with reference Figure 3 ,exist Figure 4 In the illustrated embodiment, the DAC (digital-to-analog converter) serves as... Figure 3 The first control unit 122 in the middle, the first NMOS transistor Q1 as Figure 3 The first switch 121 in the middle. AND gate G as Figure 3 In the judgment unit 131, the second NMOS transistor Q2 serves as... Figure 3 The switching control unit 132 in the middle.

[0057] In this embodiment, a first digital signal is input to the DAC, which converts the first digital signal into an analog voltage signal, namely the first control signal mentioned above, and outputs the analog voltage signal to the gate of the first NMOS transistor Q1. The drain of the first NMOS transistor Q1 is connected to the heating unit 101, and the source of the first NMOS transistor Q1 is grounded through a current-limiting resistor R0. The output of the AND gate is connected to the gate of the second NMOS transistor Q2, the source of the second NMOS transistor Q2 is grounded, and the drain of the second NMOS transistor Q2 is connected to the drain of the first NMOS transistor Q1.

[0058] The gate-source voltage difference of an NMOS transistor determines its conduction level. Therefore, by adjusting the gate voltage of the first NMOS transistor Q1, the on-resistance of the first NMOS transistor Q1 can be changed, thereby enabling the first NMOS transistor Q1 to be turned on or off, and maintaining the required current in the branch under a certain on-resistance.

[0059] Specifically, when the DAC output is low, causing Vg ≤ Vs of the first NMOS transistor Q1, Q1 is off, and no current flows through the heating unit 101, resulting in a stopped heating state. When the DAC output is high, causing Vg > Vs of the first NMOS transistor Q1, Q1 is on, and the heating unit 101 begins heating. Since the resistance of the first NMOS transistor Q1 changes with Vgs, adjusting the gate-source voltage difference Vgs adjusts the conduction level of Q1. Correspondingly, the current flowing through the heating unit 101 changes accordingly. Because the heating unit 101 shares the power supply 100 with other functional modules, to ensure that the total load current does not exceed the rated current, the first NMOS transistor Q1 can be placed at a certain on-resistance to maintain a constant current in the branch containing the current control module 102. That is, in the first heating mode, the total current flowing through the heating unit and other functional modules does not exceed the rated current.

[0060] Reference Figure 4In the embodiment of the present invention shown, to ensure that the heating unit 101 can still reach its rated power after aging, the heating power of the heating unit 101 can be adjusted by adjusting the pulse width of the first control signal. Adjusting the pulse width of the first control signal adjusts the duty cycle of the first NMOS transistor Q1, so that the heating power of the heating unit 101 reaches its rated power. Specifically, in the first heating mode, when the resistance of the heating unit-Q1-ground branch is constant, that is, the current in the circuit is maintained by the current control module 102 in the first heating mode, the power when the duty cycle of the first control signal is 100% can be calculated. Then, based on the rated power of the heating unit 101, the ratio of the two can be calculated to obtain the required duty cycle. For example, if the rated power of the heating unit 101 is 7.5W, and the power can reach 15W when the duty cycle is 100% (i.e., the first NMOS transistor Q1 is always on), then adjusting the duty cycle to 50% can achieve the desired rated power.

[0061] As can be seen, the driving circuit for heating the lidar window in this embodiment of the invention controls the current in the heating unit 101 in the first heating mode through the current control module 102. This ensures that even when other functional modules sharing the power supply with the heating unit are operating, the total load current will not exceed the rated value, thus guaranteeing circuit safety. Furthermore, by changing the pulse width of the first control signal, i.e., changing the duty cycle of the first NMOS transistor Q1, the heating unit can reach the desired power even after aging.

[0062] Figure 4 In the illustrated embodiment, the two input terminals of the AND gate G are respectively input to the first control signal HEAR_CTRL and the first enable signal HEAR_EN. Since the first enable signal HEAR_EN is mutually exclusive with the enable signal of the functional module that shares power with the heating unit 101, when the heating unit 101 is on and the functional module is not working, the AND gate G outputs a high level, causing the second NMOS transistor Q2 to turn on. Due to the very small on-resistance of the second NMOS transistor Q2, the current flowing through the heating unit 101 increases, thereby increasing the heating power of the heating unit 101, while ensuring that the total load current does not exceed the rated current. That is, in the second heating mode, the total resistance in the heating drive circuit decreases, the current increases, and thus the heating power of the heating unit 101 is improved. Furthermore, in the second heating mode (when other functional modules are not working), the current flowing through the heating unit does not exceed the rated current of the circuit.

[0063] visible, Figure 4In the embodiment of the driving circuit for heating the lidar window shown, when the second NMOS transistor Q2 is off, the current in the branch of the first NMOS transistor Q1 is fixed; when the branch of the second NMOS transistor Q2 is on, the heating power of the heating unit 101 can be increased, so that it can achieve a higher heating power.

[0064] In use, the activation of the second NMOS transistor Q2 is determined by whether the functional module sharing the power supply 100 with the heating unit 101 is operational. By switching the second NMOS transistor Q2 on and off, the current of the heating unit 101 is adjusted. This allows the heating unit 101 to provide a smaller heating power with a constant current during the operation of the functional module, and a larger heating power during the non-operational period, provided the total load current peak does not exceed the rated value. Furthermore, in the first heating mode, the current in the circuit is kept constant by adjusting the on-resistance of the first NMOS transistor Q1, ensuring that the total load current (i.e., the current of the heating unit's unconnected branch plus the operating current of the functional module sharing the power supply) is less than or equal to the rated current of the circuit. Furthermore, considering the differences in manufacturing processes between NMOS transistors, it cannot be guaranteed that the on-resistance of all NMOS transistors will be a fixed value under the same voltage. Therefore, in another non-limiting embodiment, a buffer is added between the DAC and the first NMOS transistor Q1; alternatively, a DAC with a buffer can also be used.

[0065] like Figure 5 The diagram shown is a schematic diagram of another specific implementation of the driving circuit for heating the lidar window according to an embodiment of the present invention.

[0066] and Figure 4 Unlike the illustrated embodiment, in this embodiment, the first control unit 122 includes not only the aforementioned DAC, but also a first resistor R1 and a buffer D1. The first resistor R1 is connected in series with a first NMOS transistor Q1, which serves as a first switch. The positive input terminal of the buffer D1 is connected to the output terminal of the DAC, the negative input terminal of the buffer D1 is connected to the output terminal of the first switch (i.e., the source of the first NMOS transistor Q1), and the output terminal of the buffer D1 is connected to the control terminal of the first switch (i.e., the gate of the NMOS transistor Q1).

[0067] In this embodiment, the first resistor R1 and the buffer D1 form a feedback loop to more accurately adjust the current in the heating unit—Q1—ground branch. Specifically, if the voltage output by the DAC does not allow the first NMOS transistor Q1 to conduct to the required degree, the current in the heating unit—Q1—ground branch will be small. Consequently, the source voltage of the first NMOS transistor Q1, i.e., the negative input voltage of the buffer D1, will be too small to be level with the positive input voltage of the buffer D1. Therefore, the buffer D1 will increase its output voltage to increase the conduction degree of the first NMOS transistor Q1, thereby increasing the current in the heating unit—Q1—ground branch until the negative input voltage of the buffer D1 is increased to be the same as the positive input voltage.

[0068] In addition, in this embodiment, when the second NMOS transistor Q2 is turned on, the voltage at the negative input terminal of the buffer D1 cannot be pulled high, so that the buffer D1 continuously outputs a higher level, causing the first NMOS transistor Q1 to switch from the variable resistor state to the switching state, that is, the first NMOS transistor Q1 is fully turned on. At this time, the resistance of the first NMOS transistor Q1 is very small and the power consumption is very low, thereby effectively reducing the risk of device overheating.

[0069] As can be seen, this feedback loop can also control the on-resistance of the first NMOS transistor Q1 to reach a preset value. The preset value refers to the resistance value when the first NMOS transistor Q1 is turned on, so that the current in the heating unit-Q1-ground branch reaches the required current, that is, the on-resistance of the first NMOS transistor Q1.

[0070] It should be noted that, Figure 5 In the circuit shown, the first resistor R1 can also serve as... Figure 4 The current-limiting resistor R0 in the circuit shown has a similar current-limiting effect.

[0071] exist Figure 5 In the illustrated embodiment, the first NMOS transistor Q1 operates in the variable resistance region, and the second NMOS transistor Q2 operates in switching mode. Since the resistance of the MOS transistor operating in the variable resistance region is greater than its resistance operating in switching mode, it is also possible to... Figure 5 The circuit structure of the embodiment shown is modified as follows: Figure 6 The structure shown changes the connection of the source of the second NMOS transistor Q2 from ground to the source of the first NMOS transistor Q1. This connection method does not affect the operation of the two NMOS transistors. The working principle of the modified circuit is the same as... Figure 5 The same applies as shown, so I will not repeat it here.

[0072] It should be noted that the above-described modifications also apply to those without a feedback loop. Figure 4 The circuit shown.

[0073] Furthermore, to facilitate accurate adjustment of the pulse width of the first control signal and ensure that the heating power of the heating unit 101 reaches its rated power in the first heating mode, in another embodiment of the drive circuit for heating the lidar window of this invention, a current sampling module may be included. This current sampling module is used to collect the current on the heating unit. Correspondingly, the pulse width of the first control signal is dynamically adjusted according to the current collected by the current sampling module, so that the heating power of the heating unit 101 reaches its rated power in the first heating mode. Specifically, after the first NMOS transistor Q1 is turned on, the total resistance in the heating circuit can be calculated based on the current collected by the current sampling module. Since the resistances of other components in the circuit are known, the resistance of the heating unit can be calculated, and the on-resistance of the first NMOS transistor Q1 can be adjusted to maintain the current at the desired fixed current. In addition, the pulse width of the first pulse can be calculated based on the resistance of the heating unit and the current in the circuit, i.e., the duty cycle of the first NMOS transistor Q1 can be adjusted to ensure that the heating unit reaches its rated heating power. Figure 7 As shown, in a non-limiting embodiment, the sampling circuit includes a second resistor R2 disposed on the branch where the first NMOS transistor Q1 is located, and an ADC (analog-to-digital converter) connected in parallel with the second resistor R2, wherein the second resistor R2 is disposed between the first resistor R1 and ground.

[0074] At the start of each heating cycle, the current of the heating unit 101 is indirectly measured by sampling the current in the branch containing the first NMOS transistor Q1. Specifically, the current on-resistance of the first NMOS transistor Q1 can be determined based on the voltage output from the DAC. The first resistor R1 and the second resistor R2 are known. The total resistance of the current heating circuit can be calculated based on the sampled current. Subtracting the aforementioned resistors from the total resistance yields the current resistance of the heating unit 101. Then, based on the required current and the resistance of the heating unit, the power at a 100% duty cycle can be calculated. The duty cycle, i.e., the pulse width of the first control signal, is determined based on this power and the rated power required by the heating unit. By adjusting the duty cycle, the heating power of the heating unit 101 can reach its rated power.

[0075] Furthermore, in practical applications, the aforementioned current sampling module can be used to monitor the safety of the heating module. For example, in one specific implementation, the driving circuit further includes a monitoring module (not shown) for monitoring the current collected by the current sampling module and determining whether there is a short circuit or open circuit in the heating unit branch based on the current. For instance, a safe operating current range can be set for the heating module 101. When the DAC outputs a first control signal to turn on the first NMOS transistor Q1, if the current sampling module does not detect current, it is determined that there is an open circuit in the circuit, and an alarm can be triggered. When the current detected by the current sampling module exceeds the set threshold, it is determined that there may be a short circuit in the circuit, and an alarm can be triggered and the circuit can be disconnected, such as by turning off the switch of the heating module 101 or disconnecting the entire driving circuit from the power supply 101, thereby ensuring the safety of the circuit system and preventing damage to some components of the driving circuit itself and some related components in the system.

[0076] exist Figure 7 In the illustrated embodiment, current sampling is achieved by adding a second resistor R2. In practical applications, it is also possible to perform current sampling directly using the first resistor R1 without adding a second resistor R2. Figure 8 As shown, it can achieve the same as Figure 7 The illustrated embodiment achieves the same effect.

[0077] Reference Figure 9 This is a schematic diagram of another specific implementation of the driving circuit for heating the lidar window in an embodiment of the present invention.

[0078] This embodiment and Figure 5 The embodiment shown is similar, except that a transistor is used instead. Figure 5 The MOSFET in the circuit. Specifically, in this embodiment, the first NPN transistor Q4 serves as... Figure 3 The first switch 121 in the middle, and the second NPN transistor Q5 as Figure 3 The switching control unit 132 is located in the middle. A third resistor R3 is also provided between the output terminal of the buffer D1 and the base of the first NPN transistor Q4 to limit the current.

[0079] The base of the first NPN transistor Q4 is connected to the output of the buffer D1 through the third resistor R3, the source is connected to the heating module 101, and the emitter is grounded through the first resistor R1. The base of the second NPN transistor Q5 is connected to the output of the AND gate G, the source is connected to the source of the first NPN transistor Q4, and the emitter is grounded.

[0080] The working principle of the driving circuit in this embodiment is the same as Figure 5 The embodiments shown are similar and will not be described again here.

[0081] Considering that the second NMOS transistor Q2 or the second NPN transistor Q5 in the previous embodiments operate in switching mode, in practical applications, a gating switch can also be used to replace the second NMOS transistor Q2 or the second NPN transistor Q5.

[0082] For example, refer to Figure 10 This is a schematic diagram of another specific implementation of the driving circuit for heating the lidar window in an embodiment of the present invention.

[0083] and Figure 9 The difference between the illustrated embodiment and the one shown is that in the driving circuit of this embodiment, a selection switch K is used instead of the one shown. Figure 9 The second NPN transistor Q5 in the circuit.

[0084] It should be noted that the control terminal of the selector switch K is connected to the output terminal of the AND gate G, and the input terminal is connected to the heating module 101. One of the two output terminals is grounded, and the other can be left floating or grounded through a large resistor.

[0085] The second control signal output from AND gate G controls whether the gating switch K is turned on. The control logic is the same as the control logic of the second NMOS transistor Q2 or the second NPN transistor Q5 described above, and will not be repeated here.

[0086] The above embodiments are only based on Figure 2 The present invention provides some specific circuit structure examples for the driving circuit used for heating the lidar window. It should be noted that the present invention is not limited to these example structures, and there may be other structural modifications. Any structure that can realize the above-mentioned functional units should be covered within the scope of protection of the present invention.

[0087] In this invention, the heating unit can be an ITO film, or other heating components with the same performance. This invention does not limit the specific heating unit.

[0088] The driving circuit for heating the lidar window provided in this embodiment of the invention adopts a structure design in which the driving circuit shares a power supply with other functional modules of the lidar. This eliminates the need to change the existing structure of multiple modules sharing the same power supply in lidar. By using a switching module control, the heating unit can use different heating powers according to the working state of the functional modules sharing the power supply, thereby ensuring that both the heating power and the total load current meet the requirements.

[0089] Through testing, the duty cycle switching frequency of the driving circuit for heating the lidar window provided in this embodiment of the invention is 100-200 Hz, which is a low-frequency switching frequency. There is no high-frequency switching during the entire heating process. Compared with circuits that use inductors and high-frequency switching to achieve current stability, the solution of this invention has a low switching frequency and is EMC (Electromagnetic Compatibility) friendly, and will not cause electromagnetic interference to other devices or components in its environment.

[0090] Accordingly, embodiments of the present invention also provide a heating device, including the driving circuit described above.

[0091] Accordingly, embodiments of the present invention also provide a lidar, including a laser and the heating device described above, wherein the heating device and the laser share a power supply.

[0092] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article indicates that the preceding and following related objects have an "or" relationship.

[0093] In the embodiments of this application, "multiple" refers to two or more.

[0094] The descriptions of "first," "second," etc., appearing in the embodiments of this application are for illustrative purposes and to distinguish the objects being described. They have no order and do not indicate any special limitation on the number of devices in the embodiments of this application, nor do they constitute any limitation on the embodiments of this application.

[0095] In this application embodiment, "connection" refers to various connection methods such as direct connection or indirect connection to realize signal transmission between devices. This application embodiment does not limit this in any way.

[0096] While the present invention has been disclosed above, it 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 invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A driving circuit for heating a lidar window, characterized in that, The driving circuit shares a power supply with other functional modules of the lidar, and the circuit includes: a heating unit, a current control module, and a switching module; The heating unit is connected to the power supply, and the current control module and the switching module are respectively connected to the heating unit; The switching module is configured to switch the heating unit between a first heating mode and a second heating mode based on the operating state of the functional module sharing the power supply. The heating power of the first heating mode and the second heating mode are different. When the functional module sharing the power supply is working, the heating unit uses a lower heating power in the first heating mode. When the functional module sharing the power supply is not working, the heating unit uses a higher heating power in the second heating mode. The current control module is used to adjust the current in the drive circuit under the first heating mode.

2. The driving circuit according to claim 1, characterized in that, The current control module includes: a first switch and a first control unit; The first control unit is used to control the opening and closing of the first switch.

3. The driving circuit according to claim 2, characterized in that, The first control unit is further configured to adjust the on-resistance of the first switch when the first switch is turned on.

4. The driving circuit according to claim 3, characterized in that, The first control unit receives a first digital signal and outputs a first control signal to the first switch.

5. The driving circuit according to claim 4, characterized in that, The first control unit includes a digital-to-analog converter, which outputs a first control signal and controls the first switch to be turned on or off or adjusts the on-resistance of the first switch by adjusting the magnitude of the first control signal.

6. The driving circuit according to claim 5, characterized in that, The first control unit further includes: a first resistor and a buffer; The first resistor is connected in series with the first switch; The positive input terminal of the buffer is connected to the output terminal of the digital-to-analog converter, the output terminal of the buffer is connected to the control terminal of the first switch, and the negative input terminal of the buffer is connected to the output terminal of the first switch. The first resistor and the buffer form a feedback loop, and the feedback loop controls the on-resistance of the first switch to reach a preset value.

7. The driving circuit according to claim 4, characterized in that, The first switch includes a first NMOS transistor; the first control signal is input to the gate of the first NMOS transistor.

8. The driving circuit according to claim 4, characterized in that, The first switch includes a first NPN transistor; the first control signal is input to the base of the first NPN transistor.

9. The driving circuit according to claim 4, characterized in that, The switching module includes: a judgment unit and a switching control unit; The judgment unit is used to generate a second control signal based on the first control signal and the first enable signal; the first enable signal is mutually exclusive with the enable signal of the functional module that shares the power supply with the heating unit. The switching control unit is used to control the heating unit to switch between a first heating mode and a second heating mode according to the second control signal.

10. The driving circuit according to claim 9, characterized in that, The decision unit is an AND gate.

11. The driving circuit according to claim 9, characterized in that, The switching control unit includes a second NMOS transistor; the second control signal is input to the gate of the second NMOS transistor.

12. The driving circuit according to claim 9, characterized in that, The switching control unit includes: a second NPN transistor; the second control signal is input to the base of the NPN transistor.

13. The driving circuit according to claim 9, characterized in that, The switching control unit includes: a gating switch; the second control signal is input to the control terminal of the gating switch.

14. The driving circuit according to claim 4, characterized in that, The circuit also includes: A current sampling module is used to collect the current in the drive circuit.

15. The driving circuit according to claim 14, characterized in that, The pulse width of the first control signal is dynamically adjusted according to the current collected by the current sampling module so that the heating power of the heating unit in the first heating mode reaches the rated power.

16. The driving circuit according to claim 14, characterized in that, The circuit also includes: The monitoring module is used to monitor the current collected by the current sampling module and determine whether there is a short circuit or open circuit in the heating unit branch based on the current.

17. The driving circuit according to any one of claims 1 to 16, characterized in that, The heating unit is an ITO film.

18. A heating device, characterized in that, include: The driving circuit as described in any one of claims 1 to 16.

19. A lidar, characterized in that, It includes a laser and a heating device as described in claim 18, wherein the heating device shares a power source with the laser.

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