Laser driving circuit, driving method and laser ranging device

Abstract

An embodiment of the present disclosure provides a laser driving circuit, a driving method, and a laser ranging device. The laser driving circuit includes: an impedance module, the impedance of which is adjustable; a capacitor charging and discharging module connected in series with the impedance module, the capacitor charging and discharging module including a first capacitor and a laser connected in series; wherein the impedance module is configured to be in a low-impedance state when charging the first capacitor and in a high-impedance state when discharging the first capacitor.

Description

Technical Field

[0001] The present disclosure relates to the field of laser ranging, and in particular to a laser driving circuit, a driving method and a laser ranging device. Background Art

[0002] Laser distance measurement uses a laser as a light source. Its principle is to measure the time it takes for a laser beam to travel to and from a target, and then calculate the target distance using the speed of light and the atmospheric refraction coefficient. The laser's drive circuit plays a crucial role in laser ranging performance.

[0003] Laser drive circuits are generally divided into two types: voltage-driven and current-driven. The voltage-driven drive principle includes two forms: MOS direct-driven and capacitor-discharge. Currently, both MOS direct-driven and capacitor-discharge drive circuits have some drawbacks: The laser pulse width emitted by a MOS direct-driven laser is limited by the drive signal pulse width and cannot be very narrow, resulting in low instantaneous laser energy and difficulty in increasing the laser repetition frequency. The capacitor-discharge drive circuit has a long charging time constant, slow charging, and high loss during discharge, leading to high power consumption.

[0004] Therefore, how to balance higher laser instantaneous energy, higher laser repetition frequency and lower power consumption is an urgent problem that needs to be solved. Summary of the Invention

[0005] In view of this, embodiments of the present disclosure provide a laser driving circuit, a laser driving method, and a laser ranging device.

[0006] To achieve the above objectives, the technical solution of the present disclosure is implemented as follows:

[0007] In a first aspect, an embodiment of the present disclosure provides a driving circuit for a laser, comprising: an impedance module, the impedance of which is adjustable; a capacitor charging and discharging module, connected in series with the impedance module, the capacitor charging and discharging module comprising a first capacitor and a laser connected in series; wherein the impedance module is configured to be in a low-resistance state when charging the first capacitor, and in a high-resistance state when discharging the first capacitor.

[0008] In some embodiments, the impedance module includes an adjustable resistor.

[0009] In some embodiments, the impedance module includes a first branch and a second branch; the first branch includes a first resistor, which is connected in series with the first capacitor; the second branch includes a second resistor and a second switch connected in series, and the impedance of the second resistor is less than the impedance of the first resistor; wherein, when the second switch is turned on, the second resistor is connected in parallel with the first resistor.

[0010] In some embodiments, the second switch is a field effect transistor, one of the source and drain of the second switch is connected to the second resistor, and the other of the source and drain of the second switch is electrically connected between the first resistor and the first capacitor.

[0011] In some embodiments, the impedance module further includes a third branch, the third branch includes a voltage-adjustable voltage-dividing node, and the gate of the second switch is electrically connected to the voltage-dividing node.

[0012] In some embodiments, the third branch is connected in parallel to the power supply voltage with the first branch and the second branch, and the third branch includes a third resistor, a fourth resistor and a third switch connected in series in sequence; wherein the voltage dividing node is set between the third resistor and the fourth resistor, and the third branch is grounded through the third switch.

[0013] In some embodiments, the third switch is a field effect transistor, one of the source and drain of the third switch is connected to the fourth resistor, and the other of the source and drain of the third switch is grounded.

[0014] In some embodiments, the capacitor charging and discharging module further includes a first switch and a diode, the first switch being a field effect transistor; the first end of the first capacitor is connected to the power supply voltage through the first branch, and the first end of the first capacitor is also grounded through the first switch; the second end of the first capacitor is grounded through the laser and the diode respectively.

[0015] In a second aspect, an embodiment of the present disclosure provides a laser ranging device, comprising a driving circuit of a laser as in any of the above embodiments.

[0016] In a third aspect, an embodiment of the present disclosure provides a method for driving a laser, which is applied to a driving circuit of a laser, wherein the driving circuit of the laser includes an impedance module and a capacitor charging and discharging module connected in series, the impedance of the impedance module is adjustable, and the capacitor charging and discharging module includes a first capacitor and a laser connected in series. The method includes: providing a first driving signal, the first driving signal acts on the impedance module to put the impedance module in a low-resistance state when charging the first capacitor, and put the impedance module in a high-resistance state when discharging the first capacitor; providing a second driving signal, the second driving signal acts on the capacitor charging and discharging module to put the first capacitor and the laser in an open-circuit state when charging the first capacitor, and put the first capacitor and the laser in a closed-circuit state when discharging the first capacitor.

[0017] In some embodiments, the first drive signal and the second drive signal have a signal cycle, and the signal cycle includes the following states: a capacitor charging state, a capacitor discharging state, and a default state; wherein, in the capacitor charging state and the capacitor discharging state, the phases of the first drive signal and the second drive signal are opposite.

[0018] The present disclosure provides a laser driving circuit, a driving method, and a laser ranging device. The laser driving circuit includes: an impedance module, wherein the impedance of the impedance module is adjustable; a capacitor charging and discharging module connected in series with the impedance module, wherein the capacitor charging and discharging module includes a first capacitor and a laser connected in series; wherein the impedance module is configured to be in a low-resistance state when charging the first capacitor and in a high-resistance state when discharging the first capacitor. In the present disclosure, the impedance module is connected in series with the capacitor charging and discharging module. When the impedance module is in a low-resistance state when charging the first capacitor, the charging time constant of the impedance module and the first capacitor can be reduced, the charging speed of the first capacitor can be accelerated, and the repetition frequency of the laser can be increased. The impedance module is also in a high-resistance state, causing the first capacitor to discharge to the laser, causing the laser to generate laser light. Since the impedance module is in a high-resistance state when the first capacitor is discharged, the power consumption of the laser driving circuit when the first capacitor is discharged can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of the structure of a laser driving circuit provided by an embodiment of the present disclosure;

[0020] Figure 2 A schematic diagram of the steps of a laser driving method provided in an embodiment of the present disclosure;

[0021] Figure 3 Provided for the embodiments of the present disclosure Figure 1 The driving signal phase diagram of the laser driving circuit Figure 1;

[0022] Figure 4 Provided for the embodiments of the present disclosure Figure 1 The driving signal phase diagram of the laser driving circuit Figure 2 . DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present disclosure in conjunction with the embodiments of the present disclosure and the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present disclosure.

[0024] In the following description, numerous specific details are provided to provide a more thorough understanding of the present disclosure. However, it will be apparent to those skilled in the art that the present disclosure can be practiced without one or more of these details. In other instances, certain technical features known in the art are not described to avoid confusion with the present disclosure; that is, all features of actual embodiments are not described herein, nor are well-known functions and structures described in detail.

[0025] In the drawings, the sizes of layers, regions, elements and their relative sizes may be exaggerated for clarity. Like reference numerals denote like elements throughout.

[0026] It should be understood that when an element or layer is referred to as being "on, adjacent to, connected to, or coupled to" another element or layer, it may be directly on, adjacent to, connected to, or coupled to the other element or layer, or there may be intervening elements or layers. In contrast, when an element is referred to as being "directly on, directly adjacent to, directly connected to, or directly coupled to" another element or layer, there may be no intervening elements or layers. It should be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers, and / or parts, these elements, components, regions, layers, and / or parts should not be limited by these terms. These terms are merely used to distinguish one element, component, region, layer, or part from another element, component, region, layer, or part. Therefore, without departing from the teachings of the present disclosure, the first element, component, region, layer, or part discussed below may be represented as a second element, component, region, layer, or part. However, when the second element, component, region, layer, or part is discussed, it does not necessarily mean that the first element, component, region, layer, or part exists in the present disclosure.

[0027] Spatially relative terms such as "under," "beneath," "below," "under," "above," "above," etc., may be used herein for convenience of description to describe the relationship of an element or feature shown in the figures to other elements or features. It should be understood that in addition to the orientations shown in the figures, the spatially relative terms are intended to include different orientations of the device in use and operation. For example, if the device in the drawings is flipped, then the elements or features described as "under the other elements" or "under it" or "under it" will be oriented as "on" the other elements or features. Thus, the exemplary terms "under" and "under" may include both upper and lower orientations. The device may be oriented otherwise (rotated 90 degrees or in other orientations) and the spatial descriptors used herein are interpreted accordingly.

[0028] The purpose of the terms used herein is only to describe specific embodiments and is not intended to limit the present disclosure. When used herein, the singular forms "a", "an", and "the" are intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "comprising" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0029] In order to fully understand the present disclosure, detailed steps and detailed structures will be presented in the following description to illustrate the technical solution of the present disclosure. The preferred embodiments of the present disclosure are described in detail below. However, in addition to these detailed descriptions, the present disclosure may also have other implementation methods.

[0030] An embodiment of the present disclosure provides a driving circuit for a laser, comprising: an impedance module, the impedance of the impedance module being adjustable; a capacitor charging and discharging module connected in series with the impedance module, the capacitor charging and discharging module comprising a first capacitor and a laser connected in series; wherein the impedance module is configured to be in a low-impedance state when charging the first capacitor and in a high-impedance state when discharging the first capacitor.

[0031] In some embodiments, the impedance module is connected in series with the capacitor charging and discharging module. When charging the first capacitor, the impedance module is in a low-resistance state. This can reduce the charging time constant of the impedance module and the first capacitor, speed up the charging speed of the first capacitor, and increase the repetition frequency of the laser.

[0032] In some embodiments, after the first capacitor is fully charged, the impedance module is placed in a high-impedance state, and the first capacitor is discharged to the laser, causing the laser to generate laser light. Since the impedance module is in a high-impedance state when the first capacitor is discharged, the power consumption of the laser driving circuit when the first capacitor is discharged can be reduced.

[0033] In this embodiment, the impedance module being in a low-impedance state can be understood as: the impedance value of the impedance module is less than or equal to a first impedance threshold. The first impedance threshold must meet the following conditions: when the impedance value of the impedance module is less than or equal to the first impedance threshold, the charging time constant RC of the first capacitor (R is the impedance value of the impedance module, C is the capacitance value of the first capacitor) is less than or equal to a first expected value. When the charging time constant RC of the first capacitor is less than or equal to the first expected value, the charging time constant RC is very small, and the charging speed of the first capacitor is very fast, which is conducive to increasing the charge and discharge frequency of the first capacitor, thereby increasing the repetition frequency of the laser.

[0034] Similarly, the impedance module being in a high-impedance state can be understood as meaning that the impedance value of the impedance module is greater than or equal to a second impedance threshold. The second impedance threshold must satisfy the following condition: when the impedance value of the impedance module is greater than or equal to the second impedance threshold, the current flowing through the impedance module during the discharge of the first capacitor is less than or equal to a second expected value. When the current flowing through the impedance module during the discharge of the first capacitor is less than or equal to the second expected value, the impedance power consumption of the impedance module is very low, which helps to reduce useless power consumption in the impedance module during the discharge of the first capacitor.

[0035] In some embodiments, the impedance module includes an adjustable resistor.

[0036] In some embodiments, the adjustable resistor may include a programmable resistor, a potentiometer (voltage divider), a rheostat, a trimmer, a variable resistor, etc. The adjustable resistor may be configured to be in a low-resistance state when the impedance module charges the first capacitor and in a high-resistance state when the first capacitor discharges. The resistance value of the adjustable resistor in the low-resistance state and the resistance value of the adjustable resistor in the high-resistance state may be set as required. By making the resistance of the impedance module adjustable, the charging time constant of the impedance module and the first capacitor can be adjusted to achieve adjustable repetition frequency of the laser and reduce useless power consumption of the impedance module when the first capacitor discharges.

[0037] Figure 1 This is a schematic diagram of the structure of a laser driving circuit provided by an embodiment of the present disclosure. Figure 1 As shown, the impedance module includes a first branch 110 and a second branch 120; the first branch 110 includes a first resistor R1, which is connected in series with a first capacitor C1; the second branch 120 includes a second resistor R2 and a second switch Q2 connected in series, and the impedance of the second resistor R2 is smaller than the impedance of the first resistor R1; wherein, when the second switch Q2 is turned on, the second resistor R2 is connected in parallel with the first resistor R1.

[0038] In some embodiments, when the first capacitor C1 is charged, the second switch Q2 is turned on, the second resistor R2 is connected in parallel with the first resistor R1, the second resistor R2 and the first resistor R1 form a parallel circuit and are connected in series with the capacitor charging and discharging module. At this time, the impedance module is in a low-resistance state. In the low-resistance state, its resistance is the resistance of the first resistor R1 and the second resistor R2 in parallel. This can reduce the charging time constant of the impedance module and the first capacitor, speed up the charging speed of the first capacitor, and increase the repetition frequency of the laser; when the first capacitor C1 is discharged, the second switch Q2 is turned off, the first resistor R1 is connected in series with the capacitor charging and discharging module, and the second resistor R2 is disconnected from the capacitor charging and discharging module. At this time, the impedance module is in a high-resistance state. In the high-resistance state, its resistance is equal to the resistance of the first resistor R1, which can avoid loss in the second branch 120 with a smaller resistance and reduce the power consumption of the laser driving circuit when the first capacitor is discharged.

[0039] In some embodiments, the second switch Q2 is used to control the conduction and disconnection of the second branch 120, so that the impedance module is in a low-resistance state when the first capacitor C1 is charged, and the impedance module is in a high-resistance state when the first capacitor C1 is discharged. Compared with using a separate resistance device such as a programmable resistor to control the resistance state of the impedance module, this embodiment effectively improves the integration of the laser driving circuit and can achieve a highly integrated design within the chip.

[0040] In some embodiments, the second switch is a field effect transistor, one of the source and drain of the second switch is connected to the second resistor R2 , and the other of the source and drain of the second switch is electrically connected between the first resistor R1 and the first capacitor C1 .

[0041] In some embodiments, as Figure 1 As shown, the second switch Q2 is a P-type field effect transistor, the source of the second switch Q2 is connected to the second resistor R2, and the drain of the second switch Q2 is connected between the first resistor R1 and the first capacitor C1.

[0042] In other embodiments, the second switch may be an N-type field effect transistor, the drain of the second switch is connected to the second resistor R2 , and the source of the second switch is connected between the first resistor R1 and the first capacitor C1 .

[0043] In some embodiments, the impedance module further includes a third branch 130 , the third branch 130 includes a voltage-adjustable voltage dividing node M, and the gate of the second switch Q2 is electrically connected to the voltage dividing node M.

[0044] In some embodiments, the gate voltage of the second switch Q2 is controlled by the voltage dividing node M, so that the second switch Q2 is turned on when the first capacitor C1 is charged, and is turned off when the first capacitor C1 is discharged.

[0045] In some embodiments, the third branch 130 is connected in parallel to the first branch 110 and the second branch 120 to the power supply voltage VLD, and the third branch 130 includes a third resistor R3, a fourth resistor R4 and a third switch Q3 connected in series in sequence; wherein the voltage dividing node M is set between the third resistor R3 and the fourth resistor R4, and the third branch 130 is grounded through the third switch Q3.

[0046] In some embodiments, one end of the first branch 110, the second branch 120 and the third branch 130 are all connected to the power supply voltage VLD, the other ends of the first branch 110 and the second branch 120 are connected to the capacitor charging and discharging module, and the other end of the third branch 130 is grounded through the third switch Q3.

[0047] When charging the first capacitor C1, the third switch Q3 is turned on, and the third branch 130 composed of the third resistor R3 and the fourth resistor R4 connected in series is turned on. At this time, the voltage at the end of the third resistor R3 connected to the power supply voltage VLD is VLD, and the fourth resistor R4 is grounded through the turned-on third switch Q3. At this time, the voltage at the voltage dividing node M is less than VLD, that is, the gate voltage of the second switch Q2 is less than VLD, and the gate-source voltage difference Vgs of the second switch Q2 is less than 0. Since the second switch Q2 is a P-type field effect transistor, Q2 is turned on at this time, so that the smaller second resistor R2 is connected in parallel with the larger first resistor R1, forming a low-resistance state of the impedance module; when the first capacitor C1 is discharged, the third switch Q3 is turned off. At this time, the third branch 130 is not turned on, the voltage at the voltage dividing node M is equal to VLD, that is, the gate voltage of the second switch Q2 is equal to VLD, and the gate-source voltage difference Vgs of the second switch Q2 is equal to 0. Since the second switch Q2 is a P-type field effect transistor, the second switch Q2 is turned off at this time, thereby disconnecting the smaller second resistor R2 from the parallel circuit with the larger first resistor R1, forming a high-resistance state of the impedance module. By providing the third branch 130, the gate voltage of the second switch Q2 on the second branch 120 is controlled by turning the third switch Q3 on and off, thereby controlling the turning on and off of the second switch Q2. This allows the impedance module to switch between high and low resistance states as the charge and discharge states of the first capacitor C1 change, thereby achieving rapid charging and low-power discharging.

[0048] In some embodiments, the third switch Q3 is a field effect transistor. One of the source and drain of the third switch Q3 is connected to the fourth resistor R4 , and the other of the source and drain of the third switch Q3 is grounded.

[0049] In some embodiments, as Figure 1 As shown, the third switch Q3 is an N-type field effect transistor, the drain of the third switch Q3 is connected to the fourth resistor R4, and the source of the third switch Q3 is grounded.

[0050] In some other embodiments, the third switch Q3 may be a P-type field effect transistor, a source of the third switch Q3 is connected to the fourth resistor R4 , and a drain of the third switch Q3 is grounded.

[0051] In some embodiments, the driving circuit further includes a voltage stabilizing module, which includes a second capacitor C2 and a third capacitor C3 connected in parallel, wherein the first ends of the second capacitor C2 and the third capacitor C3 are commonly connected to the power supply voltage VLD, and the second ends of the second capacitor C2 and the third capacitor C3 are both grounded, wherein the second capacitor C2 and the third capacitor C3 are filter capacitors for stabilizing the output of the power supply voltage VLD.

[0052] In some embodiments, the capacitor charge and discharge module further includes a first switch Q1 and a diode D2. The first switch Q1 is a field-effect transistor. The first end of the first capacitor C1 is connected to the power supply voltage VLD via the first branch 110, and the first end of the first capacitor C1 is also grounded via the first switch Q1. The second end of the first capacitor C1 is grounded via the laser D1 and the diode D2, respectively. The anode of the laser D1 is grounded and connected to the first end of the first capacitor C1 via the first switch Q1. The cathode of the laser D1 is connected to the second end of the first capacitor C1. The anode of the diode D2 is connected to the second end of the first capacitor C1, and the cathode of the diode D2 is coupled to the anode of the laser D1 and grounded.

[0053] In some embodiments, when charging the first capacitor C1, the first switch Q1 is turned off, and the power supply voltage VLD is charged to the first end of the first capacitor C1 through the first branch 110 and the second branch 120 connected in parallel. The second end of the first capacitor C1 is connected to the anode of the diode D2, and the cathode of the diode D2 is grounded, forming a capacitor charging path from VLD to the first branch 110 and the second branch 120 to the first capacitor C1 to the diode D2 to GND; when discharging the first capacitor C1, the first switch Q1 is turned on, and the first end of the first capacitor C1 is discharged to the laser D1 through the first switch Q1. The charge on the first end of the first capacitor C1 flows to the anode of the laser D1 via the first switch Q1, and then flows from the cathode of the laser D1 to the second end of the first capacitor C1, forming a capacitor discharging path from the first end of the first capacitor C1 to the first switch Q1 to the laser D1 to the second end of the first capacitor C1.

[0054] In some embodiments, as Figure 1 As shown, the first switch Q1 is an N-type field effect transistor, the drain of the first switch Q1 is connected to the first end of the first capacitor C1, the drain of the first switch Q1 is connected to the first branch 110 and the second branch 120, and the source of the first switch Q1 is grounded.

[0055] In other embodiments, the first switch Q1 is a P-type field effect transistor, the source of the first switch Q1 is connected to the first end of the first capacitor C1, the source of the first switch Q1 is connected to the first branch 110 and the second branch 120, and the drain of the first switch Q1 is grounded.

[0056] It should be noted that the first end and the second end of the first capacitor C1 are respectively two electrodes of the first capacitor C1.

[0057] In this embodiment, by controlling the on / off states of the first switch Q1 and the third switch Q3, the impedance state of the impedance module can be matched to the charge / discharge state of the first capacitor C1, thereby achieving rapid charging and low-power discharging. Specifically, the gate of the third switch Q3 is connected to the first drive signal DRV1, and the gate of the first switch Q1 is connected to the second drive signal DRV2. By adjusting the levels of the first drive signal DRV1 and the second drive signal DRV2, the on / off states of the first switch Q1 and the third switch Q3 can be controlled, thereby matching the impedance state of the impedance module to the charge / discharge state of the first capacitor C1. This achieves efficient and low-power driving functionality for the entire drive circuit.

[0058] In some embodiments, to improve the stability of the control of the third switch Q3 by the first drive signal DRV1 and the first switch Q1 by the second drive signal DRV2, a fifth resistor R5 and a sixth resistor R6 may be provided at the gate of the third switch Q3 and the gate of the first switch Q1, respectively. The fifth resistor R5 and the sixth resistor R6 serve as voltage-stabilizing resistors. Specifically, one end of the fifth resistor R5 is connected between the first drive signal DRV1 and the gate of the third switch Q3, and the other end of the fifth resistor R5 is grounded. One end of the sixth resistor R6 is connected between the second drive signal DRV2 and the gate of the first switch Q1, and the other end of the sixth resistor R6 is grounded.

[0059] In some embodiments, as Figure 1As shown, the first switch Q1 and the third switch Q3 are N-type field effect transistors, and the second switch Q2 is a P-type field effect transistor. When charging the first capacitor C1, the first drive signal DRV1 is at a high level. At this time, the gate voltage of the third switch Q3 is at a high level, and the source of the third switch Q3 is grounded, so that the gate-source voltage difference Vgs of the third switch Q3 is greater than 0V. At this time, the third switch Q3 is turned on, thereby making the gate voltage of the second switch Q2 less than VLD. Since the source of the second switch Q2 is connected to the power supply voltage VLD through the second resistor R2, the gate-source voltage difference Vgs of the second switch Q2 is greater than 0V. s<0V, at this time, the second switch Q2 is turned on, connecting the second resistor R2 in parallel with the first resistor R1, so that the impedance module connected in series with the first capacitor C1 is in a low-impedance state; at the same time, the second drive signal DRV2 is at a low level, at this time the gate voltage of the first switch Q1 is 0V, and the source of the first switch Q1 is grounded, so that the gate-source voltage difference Vgs of the first switch Q1 is equal to 0V. At this time, the first switch Q1 is turned off, preventing the first end of the first capacitor C1 from being grounded, thereby forming a capacitor charging path from VLD to the first branch 110 and the second branch 120 to the first capacitor C1 to the diode D2 to GND.

[0060] refer to Figure 1, after the first capacitor C1 is fully charged, the voltage at the first end of the first capacitor C1 is VLD, the voltage at the second end is equal to the voltage drop Vf of the diode D2, and the voltage difference between the first end and the second end of the first capacitor C1 is (VLD-Vf). When the first capacitor C1 is discharged, the first drive signal DRV1 is at a low level. At this time, the gate voltage of the third switch Q3 is 0V, and the source of the third switch Q3 is grounded, so that the gate-source voltage difference Vgs of the third switch Q3 is 0V. At this time, the third switch Q3 is disconnected, thereby connecting the gate of the second switch Q2 to the power supply voltage VLD through the third resistor R3, and the source of the second switch Q2 to the power supply voltage VLD through the second resistor R2. Therefore, the gate-source voltage difference Vgs of the second switch Q2 is 0V. At this time, the second switch Q2 is disconnected, disconnecting the second resistor R2 from the circuit in parallel with the first resistor R1, so that the impedance module in series with the first capacitor C1 is in a high impedance state; at the same time, the second drive signal DRV2 is at a high level. At this time, the gate voltage of the third switch Q3 is 0V, and the source of the third switch Q3 is grounded. The gate voltage of the first switch Q1 is at a high level, and the source of the first switch Q1 is grounded, so that the gate-source voltage difference Vgs of the first switch Q1 is greater than 0V. At this time, the first switch Q1 is turned on, and the first end of the first capacitor C1 is grounded through the first switch Q1. That is, the voltage at the first end of the first capacitor C1 suddenly drops to 0V. Since the voltage difference between the two ends of the first capacitor C1 cannot suddenly change, the voltage at the second end of the first capacitor C1 suddenly drops to (Vf-VLD). The anode voltage of the diode D2 also drops to (Vf-VLD). The diode D2 is disconnected because the anode voltage is lower than the cathode voltage. At this time, a capacitor discharge path is formed from the first end of the first capacitor C1 to the first switch Q1 to the laser D1 to the second end of the first capacitor C1, causing the laser D1 to generate laser light.

[0061] In some embodiments, when the first capacitor C1 is discharged, there is a conduction path with lower loss: VLD to the first resistor R1 to the first switch Q1 to GND. The power loss of this conduction path with lower loss is P=(VLD) 2 / R1, since the resistance of the first resistor R1 is very large, the loss of this path is very small, thereby achieving the effect of reducing the power consumption of the driving circuit.

[0062] In some embodiments, the laser D1 can be a single-junction laser tube or a multi-junction laser tube. Since the voltage required for the multi-junction laser tube to emit light is higher, that is, the higher the VLD, the higher the driving efficiency of the driving circuit for the multi-junction laser tube and the better the effect of reducing power consumption.

[0063] In some embodiments, the diode D2 may be a Schottky diode (voltage drop Vf is 0.3V), which can effectively improve the charging efficiency of the first capacitor C1 compared to a diode with a voltage drop of 0.7V.

[0064] An embodiment of the present disclosure also provides a laser driving method, which is applied to a laser driving circuit. The laser driving circuit includes an impedance module and a capacitor charging and discharging module connected in series. The impedance of the impedance module is adjustable. The capacitor charging and discharging module includes a first capacitor and a laser connected in series. The driving method includes: providing a first driving signal, the first driving signal acts on the impedance module to put the impedance module in a low-resistance state when charging the first capacitor, and put the impedance module in a high-resistance state when discharging the first capacitor; providing a second driving signal, the second driving signal acts on the capacitor charging and discharging module to put the first capacitor and the laser in an open-circuit state when charging the first capacitor, and put the first capacitor and the laser in a closed-circuit state when discharging the first capacitor.

[0065] The laser driving method provided in the embodiment of the present disclosure can be applied to the above-mentioned laser driving circuit embodiment, which will be described in detail below with reference to specific embodiments.

[0066] Figure 2 Schematic diagram of the steps of a laser driving method provided by an embodiment of the present disclosure. Figure 2 As shown, the laser driving method includes: step S201, providing a first driving signal, the first driving signal acts on the impedance module; step S202, providing a second driving signal, the second driving signal acts on the capacitor charging and discharging module.

[0067] In some embodiments, a first driving signal is provided, and the first driving signal acts on the impedance module to put the impedance module in a low-resistance state; a second driving signal is provided, and the second driving signal acts on the capacitor charging and discharging module to put the first capacitor and the laser in an open-circuit state to charge the first capacitor, and by putting the impedance module in a low-resistance state, the charging time constant of the impedance module and the first capacitor is reduced, the charging speed of the first capacitor is accelerated, and the repetition frequency of the laser is increased.

[0068] In some embodiments, a first driving signal is provided, and the first driving signal acts on the impedance module to put the impedance module in a high-impedance state; a second driving signal is provided, and the second driving signal acts on the capacitor charging and discharging module to put the first capacitor and the laser in a closed-circuit state, so that the first capacitor discharges to the laser, causing the laser to generate laser light, and the power consumption of the first capacitor during discharge is reduced by putting the impedance module in a high-impedance state.

[0069] In some embodiments, the first drive signal and the second drive signal have a signal cycle, and the signal cycle includes the following states: a capacitor charging state, a capacitor discharging state, and a default state; wherein, in the capacitor charging state and the capacitor discharging state, the phases of the first drive signal and the second drive signal are opposite.

[0070] Figure 3 Provided for the embodiments of the present disclosure Figure 1The driving signal phase diagram of the laser driving circuit Figure 1 ; Figure 4 Provided for the embodiments of the present disclosure Figure 1 The driving signal phase diagram of the laser driving circuit Figure 2 .

[0071] It should be noted that Figure 1 The first switch Q1 and the third switch Q3 are N-type field effect transistors, and the second switch Q2 is a P-type field effect transistor.

[0072] like Figure 3 and Figure 4 As shown, in the capacitor charging state 310, a high-level first drive signal DRV1 is provided to the gate of the third switch Q3. At this time, the gate voltage of the third switch Q3 is high, and the source of the third switch Q3 is grounded, so that the gate-source voltage difference Vgs of the third switch Q3 is greater than 0V. At this time, the third switch Q3 is turned on, thereby making the gate voltage of the second switch Q2 less than VLD. Since the source of the second switch Q2 is connected to the power supply voltage VLD through the second resistor R2, the gate-source voltage difference Vgs of the second switch Q2 is less than 0V. At this time, the second switch Q2 is turned on, and the second The resistor R2 is connected in parallel with the first resistor R1, placing the impedance module connected in series with the first capacitor C1 in a low-impedance state. Simultaneously, a low-level second drive signal DRV2 is provided to the gate of the first switch Q1. At this time, the gate voltage of the first switch Q1 is 0V, and the source of the first switch Q1 is grounded, resulting in a gate-source voltage difference Vgs of the first switch Q1 of 0V. At this time, the first switch Q1 is turned off, preventing the first end of the first capacitor C1 from being grounded. This forms a capacitor charging path from VLD to the first branch 110 and the second branch 120, to the first capacitor C1, to the diode D2, and finally to GND.

[0073] In some embodiments, after the first capacitor C1 is fully charged, the voltage at the first terminal of the first capacitor C1 is VLD, the voltage at the second terminal is equal to the voltage drop Vf of the diode D2, and the voltage difference between the first terminal and the second terminal of the first capacitor C1 is (VLD-Vf).

[0074] like Figure 3 and Figure 4As shown, in the capacitor discharge state 320, a low-level first drive signal DRV1 is provided to the gate of the third switch Q3. At this time, the gate voltage of the third switch Q3 is 0V, and the source of the third switch Q3 is grounded, so that the gate-source voltage difference Vgs of the third switch Q3 is 0V. At this time, the third switch Q3 is turned off, thereby connecting the gate of the second switch Q2 to the power supply voltage VLD through the third resistor R3, and connecting the source of the second switch Q2 to the power supply voltage VLD through the second resistor R2. Therefore, the gate-source voltage difference Vgs of the second switch Q2 is 0V. At this time, the second switch Q2 is turned off, disconnecting the second resistor R2 from the circuit in parallel with the first resistor R1, so that the impedance module connected in series with the first capacitor C1 is in a high-impedance state; at the same time, a high-level second drive signal DRV2 is provided to The gate of the first switch Q1. At this time, the gate voltage of the first switch Q1 is at a high level, and the source of the first switch Q1 is grounded, so that the gate-source voltage difference Vgs of the first switch Q1 is greater than 0V. At this time, the first switch Q1 is turned on, and the first end of the first capacitor C1 is grounded through the first switch Q1. That is, the voltage at the first end of the first capacitor C1 suddenly drops to 0V. Since the voltage difference between the two ends of the first capacitor C1 cannot suddenly change, the voltage at the second end of the first capacitor C1 suddenly drops to (Vf-VLD). The anode voltage of the diode D2 also drops to (Vf-VLD). The diode D2 is disconnected because the anode voltage is lower than the cathode voltage. At this time, a capacitor discharge path is formed from the first end of the first capacitor C1 to the first switch Q1 to the laser D1 to the second end of the first capacitor C1, causing the laser D1 to generate laser light.

[0075] In some embodiments, when the first capacitor C1 is discharged, there is a conduction path with lower loss: VLD to the first resistor R1 to the first switch Q1 to GND. The power loss of this conduction path with lower loss is P=(VLD) 2 / R1, since the resistance of the first resistor R1 is very large, the loss of this path is very small, thereby achieving the effect of reducing the power consumption of the driving circuit.

[0076] like Figure 3As shown, in the default state 330, after the first capacitor C1 is discharged, a low-level first drive signal DRV1 is provided to the gate of the third switch Q3. At this time, the gate voltage of the third switch Q3 is 0V, and the source of the third switch Q3 is grounded, so that the gate-source voltage difference Vgs of the third switch Q3 is 0V. At this time, the third switch Q3 is disconnected, thereby connecting the gate of the second switch Q2 to the power supply voltage VLD through the third resistor R3, and the source of the second switch Q2 to the power supply voltage VLD through the second resistor R2. Therefore, the gate-source voltage difference Vgs of the second switch Q2 is 0V, and the second switch Q2 is disconnected. At the same time, a low-level second drive signal DRV2 is provided to the gate of the first switch Q1. At this time, the gate voltage of the first switch Q1 is 0V, and the source of the first switch Q1 is grounded, so that the gate-source voltage difference Vgs of the first switch Q1 is 0V, and the first switch Q1 is disconnected. Figure 1 When the laser driving circuit is in the default state 330, by providing a low-level first driving signal DRV1 and a low-level second driving signal DRV2, the first switch Q1, the second switch Q2 and the third switch Q3 are all disconnected. The laser driving circuit has only one conduction path with low loss: VLD to the first resistor R1 to the first capacitor C1 to the diode D2 to GND. Since the resistance of the first resistor R1 is large, the power loss of this path is very small. At the same time, this path can also charge the first capacitor C1.

[0077] like Figure 4 As shown, the phases of the first drive signal DRV1 and the second drive signal DRV2 in the default state 410 are the same as the phases in the capacitor discharge state 320. At this time, the second switch Q2 and the third switch Q3 are disconnected, and the first switch Q1 is turned on. There is a conduction path with low loss: VLD to the first resistor R1 to the first switch Q1 to GND. Since the resistance of the first resistor R1 is large, the power loss of this path is very small. Figure 4 The phases of the first drive signal DRV1 and the second drive signal DRV2 in the default state 410 shown are the same as the phases in the capacitor discharge state 320. In a complete signal cycle, the phases of the first drive signal DRV1 and the second drive signal DRV2 only need to be changed once from the capacitor charging state 310 to the capacitor discharge state 320. In a complete signal cycle, there is no need to change the phases of the first drive signal DRV1 and the second drive signal DRV2 as shown in FIG. Figure 3 As shown, the phases of the first driving signal DRV1 and the second driving signal DRV2 are changed twice, which can simplify the phase relationship between the first driving signal DRV1 and the second driving signal DRV2.

[0078] In some embodiments, the repetition rate of the laser can be increased by reducing the length of time in the default state in each signal cycle.

[0079] An embodiment of the present disclosure further provides a laser ranging device, comprising a driving circuit for the laser as in any of the above embodiments.

[0080] In some embodiments, a laser ranging device emits a laser beam, which is then reflected by the object being measured. The laser ranging device then receives the reflected laser beam. The time difference between the time the laser beam was emitted and the time it was received is calculated. Ultimately, the target distance between the laser ranging device and the object being measured is calculated based on the time difference, the speed of light, and the atmospheric refractive index.

[0081] It should be noted that the description of the laser driving method and laser ranging device described above is similar to the description of the laser driving circuit embodiment described above, and has similar beneficial effects as the laser driving circuit embodiment. For any technical details not disclosed in the embodiments of the laser driving method and laser ranging device disclosed herein, please refer to the description of the laser driving circuit embodiment disclosed herein for an understanding.

[0082] The embodiment of the present disclosure provides a driving circuit, a driving method and a laser ranging device for a laser. The driving circuit of the laser includes: an impedance module, the impedance of the impedance module is adjustable; a capacitor charging and discharging module, which is connected in series with the impedance module, and the capacitor charging and discharging module includes a first capacitor and a laser connected in series; wherein the impedance module is configured to be in a low-resistance state when charging the first capacitor and in a high-resistance state when discharging the first capacitor. In the embodiment of the present disclosure, the impedance module is connected in series with the capacitor charging and discharging module. When the impedance module is in a low-resistance state when charging the first capacitor, the charging time constant of the impedance module and the first capacitor can be reduced, the charging speed of the first capacitor can be accelerated, and the repetition frequency of the laser can be increased; the impedance module is also in a high-resistance state, so that the first capacitor is discharged to the laser, causing the laser to generate laser light. Since the impedance module is in a high-resistance state when the first capacitor is discharged, the power consumption of the laser driving circuit when the first capacitor is discharged can be reduced.

[0083] It should be understood that “one embodiment” or “an embodiment” mentioned throughout the specification means that specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the present disclosure. Therefore, “in one embodiment” or “in an embodiment” appearing throughout the specification does not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner. It should be understood that in the various embodiments of the present disclosure, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present disclosure. The serial numbers of the embodiments of the present disclosure are for description only and do not represent the advantages and disadvantages of the embodiments.

[0084] The above description is only a preferred embodiment of the present disclosure and does not limit the patent scope of the present disclosure. All equivalent structural transformations made by using the contents of the present disclosure and the drawings under the inventive concept of the present disclosure, or direct / indirect application in other related technical fields are included in the patent protection scope of the present disclosure.

Claims

1. A laser driving circuit, characterized in that: include: An impedance module, wherein the impedance of the impedance module is adjustable; A capacitor charging and discharging module is connected in series with the impedance module, wherein the capacitor charging and discharging module includes a first capacitor and a laser connected in series; The impedance module is configured to be in a low-resistance state when charging the first capacitor and in a high-resistance state when discharging the first capacitor.

2. The driving circuit according to claim 1, wherein: The impedance module includes an adjustable resistor.

3. The driving circuit according to claim 1, wherein: The impedance module includes a first branch and a second branch; The first branch includes a first resistor, and the first resistor is connected in series with the first capacitor; The second branch includes a second resistor and a second switch connected in series, and the impedance of the second resistor is smaller than the impedance of the first resistor; When the second switch is turned on, the second resistor is connected in parallel with the first resistor.

4. The driving circuit according to claim 3, wherein: The second switch is a field effect transistor. One of the source and drain of the second switch is connected to the second resistor, and the other of the source and drain of the second switch is electrically connected between the first resistor and the first capacitor.

5. The driving circuit according to claim 4, wherein: The impedance module further includes a third branch, the third branch includes a voltage-adjustable voltage-dividing node, and the gate of the second switch is electrically connected to the voltage-dividing node.

6. The driving circuit according to claim 5, wherein: The third branch is connected in parallel with the first branch and the second branch to the power supply voltage, and the third branch includes a third resistor, a fourth resistor and a third switch connected in series in sequence; The voltage dividing node is arranged between the third resistor and the fourth resistor, and the third branch is grounded through the third switch.

7. The driving circuit according to claim 6, wherein: The third switch is a field effect transistor. One of the source and drain of the third switch is connected to the fourth resistor, and the other of the source and drain of the third switch is grounded.

8. The driving circuit according to claim 3, wherein: The capacitor charging and discharging module further includes a first switch and a diode, wherein the first switch is a field effect transistor; The first end of the first capacitor is connected to the power supply voltage through the first branch, and the first end of the first capacitor is also grounded through the first switch; the second end of the first capacitor is grounded through the laser and the diode respectively.

9. A laser ranging device, characterized in that: A driving circuit comprising the laser according to any one of claims 1 to 8.

10. A method for driving a laser, characterized in that: Applied to a driving circuit of a laser, the driving circuit of the laser includes an impedance module and a capacitor charging and discharging module connected in series, the impedance of the impedance module is adjustable, and the capacitor charging and discharging module includes a first capacitor and a laser connected in series, the method includes: providing a first driving signal, wherein the first driving signal acts on the impedance module to place the impedance module in a low-impedance state when charging the first capacitor and to place the impedance module in a high-impedance state when discharging the first capacitor; A second driving signal is provided, and the second driving signal acts on the capacitor charging and discharging module to put the first capacitor and the laser in an open circuit state when charging the first capacitor, and put the first capacitor and the laser in a closed circuit state when discharging the first capacitor.

11. The driving method according to claim 10, wherein: The first driving signal and the second driving signal have a signal cycle, and the signal cycle includes the following states: a capacitor charging state, a capacitor discharging state, and a default state; Wherein, in the capacitor charging state and the capacitor discharging state, the first driving signal and the second driving signal have opposite phases.

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