阅读说明：本技术 脉冲激光器驱动电路系统及其驱动方法 (Pulse laser driving circuit system and driving method thereof ) 是由 王玉冰 李泽安 秦莉 张明时 宋俊峰 王立军 于 2021-02-07 设计创作，主要内容包括：本发明提供一种脉冲激光器驱动电路系统及其驱动方法,其中的驱动电路系统包括电源、储能电容、电阻、放电电感、高速开关和激光器,储能电容、放电电感、高速开关与激光器串联构成放电电路,储能电容、电阻与电源串联构成充电电路,在充电电路中串联振荡电感,将充电电路变为RLC振荡电路,通过振荡方式使储能电容的充电电压高于电源的电压。与现有的供电系统相比,本发明只需在驱动电路的充电部分引入振荡电感,即可使激光器的驱动电压翻倍,成本非常低廉,性能稳定,相对于整个激光雷达系统来说几乎不增加重量,但可以将激光器对电源电压的需求降低将近一半,极大程度上降低了供电系统的成本和复杂度。(The invention provides a pulse laser driving circuit system and a driving method thereof, wherein the driving circuit system comprises a power supply, an energy storage capacitor, a resistor, a discharge inductor, a high-speed switch and a laser, the energy storage capacitor, the discharge inductor, the high-speed switch and the laser are connected in series to form a discharge circuit, the energy storage capacitor, the resistor and the power supply are connected in series to form a charging circuit, an oscillation inductor is connected in series in the charging circuit, the charging circuit is changed into an RLC oscillation circuit, and the charging voltage of the energy storage capacitor is higher than the voltage of the power supply in an oscillation mode. Compared with the existing power supply system, the invention can double the driving voltage of the laser only by introducing the oscillating inductor into the charging part of the driving circuit, has very low cost and stable performance, hardly increases the weight compared with the whole laser radar system, but can reduce the requirement of the laser on the power supply voltage by nearly half and greatly reduces the cost and the complexity of the power supply system.)

1. The utility model provides a pulse laser drive circuit system, includes power, energy storage capacitor, resistance, high speed switch, discharge inductance and laser instrument, energy storage capacitor high speed switch discharge inductance with the laser instrument establishes ties and constitutes discharge circuit, energy storage capacitor resistance with the power establishes ties and constitutes charging circuit, its characterized in that in series connection oscillating inductance in the charging circuit, will charging circuit becomes RLC oscillating circuit, makes through the oscillation mode energy storage capacitor's charging voltage is higher than the voltage of power.

2. A driving method of a pulse laser driving circuit system is characterized by comprising the following steps:

s1, charging the energy storage capacitor in an oscillation mode through an RLC oscillation circuit formed by connecting the energy storage capacitor, a resistor, an oscillation inductor and a power supply in series, so that the energy storage capacitor obtains a charging voltage higher than the power supply voltage;

and S2, closing the high-speed switch, and releasing the stored charges through the energy storage capacitor to drive the laser.

3. The driving method of the pulse laser driving circuit system according to claim 2, wherein the laser is driven by maximizing a charging voltage of the energy storage capacitor when the high-speed switch is closed.

4. The driving method of the pulse laser driving circuit system according to claim 3, wherein the inductance of the oscillating inductor is calculated based on the capacitance of the energy storage capacitor, the resistance of the resistor, and the time interval between two times of closing of the high speed switch, so that the frequency cycle of the high speed switch matches the oscillation cycle of the RLC oscillating circuit, and when the high speed switch is closed, the charging voltage of the energy storage capacitor is at the highest point of oscillation.

Technical Field

The invention relates to the technical field of laser radars, in particular to a pulse laser driving circuit system and a driving method thereof.

Background

With the continuous development of laser technology, lasers are widely applied in the field of laser radars (lidar). The remote sensing method for measuring the target distance by utilizing the laser beam has wide application prospect in the fields of military affairs, scientific research, civil use and the like. In particular, laser radar is widely used in vehicle driving assistance systems as an important sensor of remote sensing systems.

The most widely used ranging method is the pulse time of flight (TOF) method. The TOF ranging method is a two-way ranging technique that measures the distance to a target using the round-trip time of a transmitted signal from a transmitter to a receiver. The width of a pulse signal emitted by the laser is as narrow as possible, so that higher detection precision is realized; the peak power of the pulse signal is as large as possible, thereby achieving a longer detection distance. This puts high demands on the design of the laser driver circuit.

At present, the most common pulse laser driving circuit is shown in fig. 1, in which a power supply, a resistor and an energy storage capacitor form a charging part of the driving circuit, and the energy storage capacitor, a high-speed switch, a discharging inductor and a laser form a discharging part of the driving circuit. When the high-speed switch is switched off, the power supply charges the energy storage capacitor, and when the switch is switched on, the charges stored in the energy storage capacitor are completely released to drive the laser to generate pulse laser. The pulse signal source controls the high-speed switch to be periodically switched on and switched off, and the laser emits periodic high-power narrow pulses. However, the laser has a high requirement on the driving voltage, and usually needs a power supply of tens of volts or even hundreds of volts, which results in a complex and heavy power supply system, not only increases the cost, but also reduces the portability of the laser radar.

Disclosure of Invention

Aiming at the problems of complexity, heaviness and high cost of the existing power supply system of the pulse laser radar, the invention provides a novel pulse laser driving circuit system and a driving method thereof, which can double the driving voltage of a laser.

In order to achieve the purpose, the invention adopts the following specific technical scheme:

the invention provides a pulse laser driving circuit system which comprises a power supply, an energy storage capacitor, a resistor, a discharge inductor, a high-speed switch and a laser, wherein the energy storage capacitor, the high-speed switch, the discharge inductor and the laser are connected in series to form a discharge circuit, the energy storage capacitor, the resistor and the power supply are connected in series to form a charging circuit, an oscillation inductor is connected in series in the charging circuit, the charging circuit is changed into an RLC oscillation circuit, and the charging voltage of the energy storage capacitor is higher than the voltage of the power supply in an oscillation mode.

The invention provides a driving method of a pulse laser driving circuit system, which comprises the following steps:

s1, charging the energy storage capacitor in an oscillation mode through an RLC oscillation circuit formed by connecting the energy storage capacitor, a resistor, an oscillation inductor and a power supply in series, so that the energy storage capacitor obtains a charging voltage higher than the power supply voltage;

and S2, closing the high-speed switch, and releasing the stored charges through the energy storage capacitor to drive the laser.

Preferably, when the high-speed switch is closed, the charging voltage of the energy storage capacitor reaches a maximum value, and the laser is driven.

Preferably, the inductance of the oscillating inductor is calculated according to the capacitance of the energy storage capacitor, the resistance value of the resistor and the time interval between two times of closing of the high-speed switch, so that the frequency period of the high-speed switch is matched with the oscillation period of the RLC oscillating circuit, and when the high-speed switch is closed, the charging voltage of the energy storage capacitor is at the highest point of oscillation.

Compared with the existing power supply system, the invention can double the driving voltage of the laser only by introducing the oscillating inductor into the charging part of the driving circuit, has very low cost and stable performance, hardly increases the weight compared with the whole laser radar system, but can reduce the requirement of the laser on the power supply voltage by nearly half and greatly reduces the cost and the complexity of the power supply system.

Drawings

FIG. 1 is a schematic diagram of a prior art pulsed laser drive circuit;

FIG. 2 is a schematic diagram of pulsed laser drive circuitry according to one embodiment of the present invention;

FIG. 3 is an equivalent circuit diagram of pulsed laser drive circuitry during charging according to one embodiment of the present invention;

FIG. 4 is a graph of simulation results of laser current according to embodiment 1 of the present invention;

fig. 5 is a graph of simulation results of laser current according to embodiment 2 of the present invention.

Wherein the reference numerals include: the laser comprises a power supply 1, an energy storage capacitor 2, a resistor 3, a high-speed switch 4, a laser 5, a discharge inductor 6 and an oscillation inductor 7.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same reference numerals are used for the same blocks. In the case of the same reference numerals, their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not to be construed as limiting the invention.

As background art shows, the conventional pulse laser has a high requirement on the driving voltage, and many laser radar systems are difficult to meet the requirement on the driving voltage of the laser, which affects the maximum detection distance of the laser radar.

The research shows that although the pulse laser has high requirement on the driving voltage, the pulse laser does not need a constant high-voltage power supply, as long as the energy storage capacitor is charged to the required voltage before the energy storage capacitor is discharged every time, and the RLC oscillation circuit can generate the voltage higher than the power supply in an oscillation mode and has an inherent oscillation period, so that the RLC oscillation circuit is particularly suitable for the pulse laser driving circuit and provides the voltage higher than the power supply for the laser.

The invention is tested and verified by the theory, an oscillating inductor is introduced into the charging part of the driving circuit, so that the power supply, the oscillating inductor, the resistor and the energy storage capacitor form an RLC oscillating circuit, the laser is a pulse laser diode, the capacitor is 1nF, the oscillating inductor is 10.1mH, and the power supply is 32V. Through tests, the power emitted by the 32V power supply driven laser after the oscillating inductor is introduced is completely equivalent to the power emitted by a 60V power supply driven laser of a traditional circuit, after the 32V power supply is changed into a 42V power supply, the power emitted by the driven laser is equivalent to the power emitted by an 80V power supply driven laser of the traditional circuit, and the driving voltage of the laser is improved by 88-90% by the RLC oscillating circuit and is close to the doubling effect. The requirement on the precision and the internal resistance of the oscillation inductor is low, the introduced oscillation inductor can be slightly larger than a theoretical calculated value, and the oscillation inductor with the voltage of 10 mH-20 mH is introduced into the circuit in the test, so that a good effect can be achieved. The internal resistance of the oscillating inductor used in the experiment is 20 omega, and the amplification effect of the RLC oscillating circuit on the power supply voltage is not influenced by the existence of the internal resistance.

The following describes in detail a pulsed laser driving circuit system and a driving method thereof according to an embodiment of the present invention, respectively, with reference to the accompanying drawings.

Fig. 2 illustrates the principle of the pulsed laser drive circuitry according to one embodiment of the present invention.

As shown in fig. 2, a pulse laser driving circuit system according to an embodiment of the present invention includes: power 1, energy storage capacitor 2, resistance 3, high speed switch 4, laser instrument 5 and discharge inductance 6, power 1, energy storage capacitor 2 and resistance 3 establish ties and form charging circuit, energy storage capacitor 2, high speed switch 4, laser instrument 5 establishes ties with discharge inductance 6 and forms discharge circuit, when high speed switch 4 disconnection, charge energy storage capacitor 2 through power 1, when high speed switch 4 closed, energy storage capacitor 2 releases the electric charge of storage completely, drive laser instrument 5 produces pulsed laser.

The innovation of the invention is that an oscillating inductor 7 is introduced into a charging circuit, the oscillating inductor 7 is connected in series in the charging circuit, the oscillating inductor 7, a power supply 1, an energy storage capacitor 2 and a resistor 3 are connected in series, so that the original charging circuit is changed into an RLC second-order differential oscillating circuit, and the energy storage capacitor 2 can obtain a voltage higher than that of the power supply 1 within a period of time according to the principle characteristic of the differential oscillating circuit.

Because the RLC second-order differential oscillating circuit has a fixed oscillating period and the closing time of the high-speed switch 4 also has a fixed frequency period, the frequency period when the high-speed switch 4 is closed can be matched with the oscillating period of the RLC second-order differential oscillating circuit by calculating the inductance of the oscillating inductor 7, so that the charging voltage of the energy storage capacitor 2 just reaches the maximum value when the high-speed switch 4 is closed, and the laser 5 is driven.

Fig. 3 is an equivalent circuit of the pulse laser driving circuitry at the time of charging according to one embodiment of the present invention.

As shown in fig. 3, when the high-speed switch 4 is turned off, the amplifying circuit is turned off, and the driving circuit is equivalent to an RLC second-order differential oscillating circuit, which has the following components according to kirchhoff's law:

U＝u_L(t)+u_R(t)+u_C(t) (1)

u_R(t)＝i(t)R (3)

formula (5) relates to u_C(t) second order constant coefficient differential equation ofy＝u_C(t) then the equation can be written as y "+ ay' + by ═ c. For this equation, a general solution Y of the homogeneous equation Y "+ ay ' + by ═ 0 is first solved, and then a specific solution Y of the inhomogeneous equation Y" + ay ' + by ═ c is solved, and Y + Y is a general solution of Y "+ ay ' + by ═ c.

Firstly, the general solution of homogeneous equation y '+ ay' + by ═ 0 is solved, and the characteristic equation is r²+ ar + b is 0, the characteristic root is(for weakly damped oscillation circuits, a)²-4b < 0) to obtainSo the solution of the next equation y "+ ay' + by ═ 0 is:

k₁、k₂is the undetermined coefficient.

One particular solution of the non-homogeneous equation y "+ ay' + by ═ c is

The general solution of the non-homogeneous equation y "+ ay' + by ═ c is:

wherein y＝u_C(t)，k₁、k₂And R is the resistance value of the resistor 3, C is the capacitance of the energy storage capacitor 2, and L is the inductance of the oscillating inductor 7.

When t is 0, the current in the circuit is zero and the voltage of the energy storage capacitor 2 is zero, depending on the initial conditions of the circuit, so thatu_C(0) 0, can be determined according to this condition

Non homogeneous equationThe general solution of (A) is as follows:

wherein

It can be seen that u_C(t) oscillation with time, u_C(t) the first maximum point of oscillation is u_C(t) maximum value.

Order toThe time of the first extreme point can be determined

Calculating correspondence according to R, C and T value of time interval between two times of switch closureL of (1), when the high-speed switch 4 is closed, u is exactly_C(t) at the highest point of oscillation, in this case

In factTherefore, it is not only easy to useThe driving voltage of the laser can be increased from U to 2U, and the effect of doubling the voltage is achieved.

That is, according toThe inductance of the oscillating inductor 7 is selected to ensure that u is exactly equal to u when the high-speed switch 4 is closed each time_C(t) at the highest point of oscillation.

The above details describe the structure and the operation principle of the pulse laser driving circuit system provided by the present invention. Corresponding to the driving circuit system, the invention also provides a driving method of the pulse laser driving circuit system.

The driving method of the pulse laser driving circuit system provided by the embodiment of the invention comprises the following steps:

and S1, charging the energy storage capacitor in an oscillation mode through an RLC oscillation circuit formed by connecting the energy storage capacitor, the resistor, the oscillation inductor and the power supply in series, so that the energy storage capacitor obtains a charging voltage higher than the power supply voltage.

The energy storage capacitor, the resistor and the power supply are connected in series to form a charging circuit, the charging circuit is connected in series in the charging circuit by introducing an oscillating inductor, the charging circuit is changed into an RLC second-order differential oscillating circuit, and the energy storage capacitor can obtain voltage higher than the power supply in a period of time in an oscillating mode according to the principle characteristic of the differential oscillating circuit.

And S2, closing the high-speed switch, and releasing the stored charges through the energy storage capacitor to drive the laser.

The high-speed switch, the energy storage capacitor, the discharge inductor and the laser are connected in series to form a discharge circuit. When the high-speed switch is closed, the charges stored in the energy storage capacitor are completely released, and the laser is driven to generate pulse laser.

Since the charging voltage of the energy storage capacitor is higher than the voltage of the power supply, the laser can obtain a driving voltage higher than the power supply.

In one embodiment of the invention, the laser is driven by maximizing the charging voltage of the energy storage capacitor when the high speed switch is closed. The invention calculates the inductance of the oscillating inductor according to the capacitance of the energy storage capacitor, the resistance value of the resistor and the time interval of two-time closing of the high-speed switch, so that the frequency period of the high-speed switch is matched with the oscillation period of the RLC oscillating circuit, and when the high-speed switch is closed, the charging voltage of the energy storage capacitor is at the highest point of oscillation.

The specific way of calculating the inductance of the oscillating inductor is referred to above, and therefore is not described herein again.

In order to demonstrate the technical effects that the present invention can achieve, two specific examples are described below.

Detailed description of the preferred embodiment 1

Fig. 4 shows the laser current simulation result according to specific embodiment 1 of the present invention.

As shown in fig. 4, the three curves respectively correspond to the simulation results of the laser current of 30V power supply without inductance, 30V power supply with inductance, and 60V without inductance, where t is the simulation time and I is the laser current. It can be seen that under a 30V power supply, the peak current of the laser can be doubled by introducing a proper inductance, and the effect is equivalent to that of a laser driven by a 60V power supply.

Specific example 2

Fig. 5 is a graph showing the simulation result of the laser current according to embodiment 2 of the present invention.

As shown in fig. 5, similar simulation is performed by using a 40V power supply, and it can also be seen that, under the 40V power supply, the peak current of the laser can be doubled by introducing a suitable oscillating inductor, and the effect is equivalent to that of a laser driven by an 80V power supply. According to the simulation result, under different power supply voltages, the power supply voltage can be doubled by introducing proper oscillation inductance.

Compared with the existing driving circuit, the invention only introduces an oscillating inductor into the charging circuit, has very low cost and stable performance, hardly increases the weight compared with the whole laser radar system, but can reduce the requirement of the laser on the power supply voltage by nearly half and greatly reduces the cost and the complexity of a power supply system. Even for some existing circuits which cannot be modified after being formed, the problem can be solved by externally connecting a series inductor. The invention provides an idea, which is not limited to the test, and a plurality of driving circuits of the pulse laser can be improved in the way, so that the invention has wide application prospect in the future.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

The above embodiments of the present invention should not be construed as limiting the scope of the present invention. Any other corresponding changes and modifications made according to the technical idea of the present invention should be included in the protection scope of the claims of the present invention.