Multiplexed control semiconductor laser module

Abstract

The application provides a multi-channel control semiconductor laser module, which can be applied to the fields of circuit design and semiconductor chip packaging technology and comprises a multi-channel driving circuit and a multi-channel signal circuit, wherein the multi-channel driving circuit shares a driving power supply; each channel of the driving circuit comprises an energy storage capacitor, a switch and a semiconductor laser, wherein the energy storage capacitors in each channel of the driving circuit are connected in parallel; each channel of the signal circuit comprises a signal source and a signal circuit unit, the signal circuit unit is connected to the switch in one-to-one correspondence and is used for controlling the on-off of the switch; a first electrode of the semiconductor laser is connected to a common total energy storage capacitor, and a second electrode of the semiconductor laser is connected to the switch to form a drivable driving loop. The independent pulse signals applied to each channel of the semiconductor laser are used for controlling the alternate emission signals of the multi-channel semiconductor laser, and by regulating the phase of each channel of the input signal, the full-time-domain pulse laser signal can be realized on one semiconductor laser module.

Description

Technical Field

[0001] This invention relates to the fields of circuit design and semiconductor chip packaging technology, and in particular to a multi-channel controlled semiconductor laser module. Background Technology

[0002] Narrow-pulse-width semiconductor laser modules mainly consist of control circuitry and a semiconductor laser. These modules are assembled through packaging processes. Under the influence of a driving power supply and pulse signals, the module can output laser signals with instantaneous power exceeding 100 watts and pulse widths in the nanosecond range, enabling rapid long-distance scanning in space. Narrow-pulse-width semiconductor laser modules offer advantages such as short signal generation time, long detection distance, and high reliability, showing broad application prospects in fields such as autonomous driving, artificial intelligence object recognition, spatial ranging, and gas monitoring. Currently, narrow-pulse-width semiconductor laser modules suffer from limitations in scanning angle and module size, stray parameters caused by components and packaging processes during circuit board fabrication, poor power consistency among multiple signals, broadening of the nanosecond-level driving current signal, and the risk of recoil current burning out the semiconductor laser. Summary of the Invention

[0003] (a) Technical problems to be solved

[0004] To address at least one of the aforementioned problems in existing narrow-pulse-width semiconductor laser modules, embodiments of the present invention provide a multi-channel controlled semiconductor laser module. By ensuring that each channel does not share a signal source, independent control of each semiconductor laser is achieved. By applying pulse signals of different phases to each semiconductor laser channel to control the alternating emission signals of the multiple semiconductor lasers, full-time-domain pulsed laser signals can be realized on a single semiconductor laser module. This achieves full-time-domain coverage of the detection space, effectively improving the module's detection capability. The multi-channel control circuit also reduces the requirements for the driving power supply, avoids signal crosstalk that exists when multiple channels are operating, and improves the module's reliability.

[0005] (II) Technical Solution

[0006] To address the aforementioned technical problems, embodiments of the present invention propose a multi-channel controlled semiconductor laser module.

[0007] According to a first aspect of the present invention, a multi-channel controlled semiconductor laser module is provided, comprising: a multi-channel driving circuit and a multi-channel signal circuit, wherein the multi-channel driving circuits share a common driving power supply; each driving circuit in the multi-channel driving circuit includes an energy storage capacitor, a switch, and a semiconductor laser; the energy storage capacitors in each driving circuit are connected in parallel to form a common total energy storage capacitor for supplying power to the semiconductor laser in each driving circuit; each signal circuit in the multi-channel signal circuit includes a signal source and a signal circuit unit, the signal circuit unit being connected to the switch in a one-to-one correspondence for controlling the switching on and off; the first electrode of the semiconductor laser is connected to the common total energy storage capacitor, and the second electrode of the semiconductor laser is connected to the switch to form a conductive driving loop.

[0008] In some exemplary embodiments, the energy storage capacitor is connected to a common drive power supply. When the switch is open, the drive power supply charges the energy storage capacitor, and when the switch is closed, the energy storage capacitor discharges to drive the semiconductor laser.

[0009] In some exemplary embodiments, capacitors, switches, semiconductor lasers, and pads are periodically arranged on the circuit board; and the semiconductor lasers are connected to the circuit board via pads using wire bonding.

[0010] In some exemplary embodiments, the periodic spacing between similar components is no greater than 10 mm; and the absolute value of the difference in periodic spacing between different components is no greater than 5 mm.

[0011] In some exemplary embodiments, the energy storage capacitor includes either a silicon capacitor or a chip capacitor.

[0012] In some exemplary embodiments, the first electrode of the energy storage capacitor is packaged on a circuit board using surface mount technology; the second electrode of the energy storage capacitor is connected to a semiconductor laser; wherein the second electrode of the energy storage capacitor is connected to the first electrode of the semiconductor laser by wire bonding; and the second electrode of the semiconductor laser is bonded to a pad by wire bonding or directly to a pad.

[0013] In some exemplary embodiments, when the electrode area of ​​the energy storage capacitor is larger than the electrode area of ​​the semiconductor laser, a stereolithography process is used. The first electrode of the energy storage capacitor is packaged on the circuit board using surface mount technology. The second electrode of the energy storage capacitor is directly attached to the first electrode of the semiconductor laser and directly connected by conductive solder. The second electrode of the semiconductor laser is bonded to the pads by wires.

[0014] In some exemplary embodiments, the number and value of the energy storage capacitors connected in parallel in the multi-drive circuit can be infinitely adjusted. By precisely controlling the value of the parallel capacitors, the capacitive reactance matching of the multi-drive circuit and the corresponding signal circuit can be completed simultaneously.

[0015] In some exemplary embodiments, each drive circuit in the multi-channel drive circuit includes multiple semiconductor lasers, wherein the multiple semiconductor lasers are connected in series or in parallel to achieve the technical effect of single-channel control of multiple semiconductor lasers.

[0016] In some exemplary embodiments, a semiconductor laser can be replaced by a component for converting pulsed electrical signals into other signals.

[0017] (III) Beneficial Effects

[0018] As can be seen from the above technical solutions, the multi-channel controlled semiconductor laser module provided by the embodiments of the present invention has at least the following beneficial effects:

[0019] (1) Each channel does not share a signal source, enabling independent control of each semiconductor laser. By applying an independent pulse signal to each semiconductor laser to control the alternating emission signals of multiple semiconductor lasers, a full-time-domain pulsed laser signal can be realized on a single semiconductor laser module. This achieves full-time-domain coverage of the detection space and effectively improves the module's detection capability.

[0020] (2) The multi-channel shared energy storage power supply circuit reduces the requirements for the driving power supply. Each channel inputs an independent pulse signal. By adjusting the phase of the signal to stagger the working time of each semiconductor laser, signal crosstalk that exists when multiple channels are working is avoided, the reliability of the module is improved, and the trial life of the module is extended.

[0021] (3) The multi-channel control adopts a shared drive power supply design and a shared total energy storage capacitor for charging, thereby achieving module miniaturization. The parallel equivalent large energy storage capacitor can reduce the influence of parasitic inductance on the drive current characteristics during the actual circuit operation, obtain a narrow rise and fall edge pulse signal, and achieve multi-channel control of the semiconductor laser module with low reverse current. Attached Figure Description

[0022] The above-described features, other objects, and advantages of the present invention will become clearer from the following description of embodiments of the invention with reference to the accompanying drawings, in which:

[0023] Figure 1 The schematic diagram illustrates a circuit structure of a multi-channel controlled semiconductor laser module according to an embodiment of the present invention;

[0024] Figure 2 This schematically illustrates a three-dimensional layout diagram of the components of a multi-channel controlled semiconductor laser module according to an embodiment of the present invention;

[0025] Figure 3This schematically illustrates a two-dimensional layout of components in a multi-channel controlled semiconductor laser module according to an embodiment of the present invention; and

[0026] Figure 4 The illustration shows a narrow pulse width low-direction current drive current signal generated by a multi-channel controlled semiconductor laser module according to an embodiment of the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0028] Figure 1 The schematic diagram illustrates a circuit structure of a multi-channel controlled semiconductor laser module according to an embodiment of the present invention.

[0029] Depend on Figure 1 As can be seen, a multi-channel controlled semiconductor laser module according to an embodiment of the present invention includes: a multi-channel driving circuit and a multi-channel signal circuit, wherein the multi-channel driving circuits share a common driving power supply; each driving circuit in the multi-channel driving circuit includes an energy storage capacitor, a switch, and a semiconductor laser; the energy storage capacitors in each driving circuit are connected in parallel to form a common total energy storage capacitor, which is used to power the semiconductor laser in each driving circuit; each signal circuit in the multi-channel signal circuit includes a signal source and a signal circuit unit, and the signal circuit unit is connected to the switch in a one-to-one correspondence, which is used to control the on / off state of the switch; the first electrode of the semiconductor laser is connected to the parallel energy storage capacitor of the corresponding branch, and the second electrode of the semiconductor laser is connected to the switch to form a conductive driving loop.

[0030] In this embodiment of the invention, each channel does not share a signal source, enabling independent control of each semiconductor laser. By applying an independent pulse signal to each semiconductor laser, the alternating emission signals of multiple semiconductor lasers are controlled. By adjusting the phase of each pulse signal, a full-time-domain pulsed laser signal can be achieved on a single semiconductor laser module. This achieves full-time-domain coverage of the detection space, effectively improving the module's detection capability. The multi-channel control circuit also reduces the requirements for the drive power supply, avoids signal crosstalk that exists when multiple channels are operating, and improves the module's reliability.

[0031] In this embodiment of the invention, the energy storage capacitor is connected to a common driving power supply. When the switch is open, the driving power supply charges the energy storage capacitor, and when the switch is closed, the driving circuit discharges to drive the semiconductor laser. Understandably, the switch is controlled by a signal circuit, with the effective pulse width of the pulse signal controlling the on-time of the driving circuit. The semiconductor laser has a small threshold current, fast response speed, and high output power. When the driving circuit is closed, the energy storage capacitor discharges to the semiconductor laser, and the semiconductor laser makes an instantaneous response to the output current of the energy storage capacitor. The output power has a linear relationship with the current; within the operating current range of the semiconductor laser, the higher the current, the higher the output power.

[0032] Figure 2 The diagram illustrates a three-dimensional layout of components in a multi-channel controlled semiconductor laser module according to an embodiment of the present invention.

[0033] like Figure 2 As shown, in a multi-channel controlled semiconductor laser module according to an embodiment of the present invention, the electronic components constituting a complete driving circuit, such as switches, parallel capacitors, and semiconductor laser arrays, are aligned horizontally and vertically, spaced evenly, and arranged periodically and closely. The maximum distance between different components does not exceed 10mm. When the semiconductor laser is connected by wire bonding, the pads reserved on the circuit board (PCB) for connecting the semiconductor laser and the driving circuit should also be closely connected to the switches, energy storage capacitors, and semiconductor lasers on the circuit board, with the maximum distance between different components not exceeding 10mm. The emitting surface of the side-emitting semiconductor laser is its side end face, and the electrodes are located on its upper and lower surfaces, unlike the electrodes of general electronic components which are located on the bottom surface. Therefore, the upper electrode of the side-emitting semiconductor laser is usually led out by gold wire and connected to the pad, and the lower electrode is connected to the pad by solder.

[0034] In this embodiment of the invention, the switch, energy storage capacitor, semiconductor laser, and pads are arranged at equal intervals and in a periodic pattern. The periodic spacing between similar components is controlled within 10 mm, and the difference in periodic spacing between different components is controlled within 5 mm. This design ensures that the total loop length deviation of different single loops is within 20 mm, reducing the impact of wire differences on circuit impedance characteristics.

[0035] Figure 3 The diagram illustrates a two-dimensional layout of components in a multi-channel controlled semiconductor laser module according to an embodiment of the present invention.

[0036] like Figure 3As shown, in an embodiment of the present invention, the parallel energy storage capacitor of a multi-channel controlled semiconductor laser module has an equal periodic spacing with the semiconductor laser, ensuring that the wire bonding length of any single channel is consistent, thus guaranteeing consistent impedance characteristics of the semiconductor laser layout across multiple control channels. When the semiconductor laser is connected by wire bonding, the PCB board has reserved pads for connecting the semiconductor laser and the driving circuit via wire bonding; the periodic spacing of these pads should be equal to that of the semiconductor laser. Periodic spacing for similar components includes, but is not limited to, […]. Figure 3 The spacings a, e, f, g, etc. described in the text refer to the periodic spacing of different components, including but not limited to the following. Figure 3 The spacing parameters b, c, d, etc., described in the text are also applicable when components are arranged periodically in a curved pattern.

[0037] Furthermore, when using silicon capacitors, chip capacitors, or other electrode energy storage capacitors that support wire bonding technology, one electrode of the energy storage capacitor is packaged on the circuit board using surface mount technology, and the other electrode is connected to the semiconductor laser via wire bonding. In this case, the distance between the semiconductor laser and the energy storage capacitor can be reduced to within 0.5mm. The other electrode of the semiconductor laser is either bonded to the PCB pads via wire bonding or directly connected to the PCB pads.

[0038] Preferably, when the electrode area of ​​the selected silicon capacitor and chip capacitor is larger than the electrode area of ​​the semiconductor laser, one electrode of the energy storage capacitor is packaged on the circuit board using surface mount technology. This allows the electrode of the semiconductor laser to be directly bonded to the capacitor electrode via conductive solder. The other electrode of the semiconductor laser is bonded to the PCB pads via leads. In this case, the distance between the semiconductor laser and the energy storage capacitor can be reduced to less than 0.1 mm.

[0039] In some exemplary embodiments, the number and value of the energy storage capacitors in the driving circuit can be adjusted to achieve capacitive reactance matching between the driving circuit and the signal circuit. For example, by changing the number and value of the energy storage capacitors corresponding to the semiconductor laser in a single channel, capacitive reactance matching of all driving circuits and signal circuits in the multi-channel control module can be completed at once.

[0040] In some exemplary embodiments, each drive circuit in the multi-channel drive circuit includes multiple semiconductor lasers, wherein the multiple semiconductor lasers are connected in series or in parallel to achieve the technical effect of single-channel control of multiple semiconductor lasers.

[0041] In some exemplary embodiments, a semiconductor laser can be replaced by a component for converting high- and low-frequency electrical signals into other signals, such as a light-emitting diode (LED), a speaker, etc.

[0042] Example 1:

[0043] Components with a 0603 package size and a side-emitting semiconductor laser are used to illustrate the component size layout. A four-channel control module, consisting of four discrete semiconductor lasers, uses a shared drive power supply as its bus power supply (V). BUS Based on the voltage-power relationship of the semiconductor laser, select V. BUS A field-effect transistor (MOSFET) is selected as the switch control driver circuit for turning on and off; the MOSFET gate is controlled by a signal circuit. The positions of the MOSFET, energy storage capacitor, and semiconductor laser are as follows: Figure 3 As shown, the four components are arranged in a neat, dense array, with all spacing less than 2mm. The two stages of the semiconductor laser are led out via pads, which connect to the drive power supply and energy storage capacitor via a circuit board. The narrow pulse width of the semiconductor laser signal requires the drive circuit to output tens of amperes of current with a pulse width in the nanosecond range. The narrow pulse width limitation requires minimizing the rise and fall times of the current. The drive circuit can be considered equivalent to a series circuit consisting of a capacitor, parasitic inductance, and a laser diode. When the laser diode is forward-biased, it can be considered a resistor, and the inductance of each part of the circuit is uniformly represented as parasitic inductance. According to the resistor-inductor-capacitor (RLC) series second-order circuit model (the RLC series second-order circuit model is a circuit structure composed of a resistor (R), inductor (L), and capacitor (C) connected in series), the relationships between the resistance (R), inductance (L), capacitor (C), current (I), and voltage (U) in the circuit are:

[0044] (1)

[0045] In the formula, t represents time. The circuit operates in an underdamped state, with both current and voltage decaying sinusoidally. The current is zero at the instant the circuit is turned on, and LdI / dT = U. Substituting the above formula into the initial conditions, we obtain:

[0046] (2)

[0047] The results of the analysis When the constant condition is met, the resulting pulse current signal shows the trend shown in the figure below. The rising and falling edges are related to the value of the parasitic inductance. The smaller the parasitic inductance, the narrower the rising and falling edges of the pulse, and the smaller the recoil signal.

[0048] Because current has sinusoidal characteristics, forward and reverse current signals are generated alternately, forming a current cycle. When the reverse current signal is too large, it will break down the active light-emitting region of the semiconductor laser composed of the PIN structure, destroying the semiconductor laser. For the drive circuit in underdamped operating mode, the parasitic inductance of the loop is much smaller than the resistance. Substituting this numerical relationship into equation (2), we can see that the reverse current signal and the parasitic inductance have an almost exponential functional relationship. The larger the parasitic inductance, the larger the reverse current signal. The reverse current in the first current signal cycle has the greatest impact on device performance. In the actual device fabrication process, the parasitic inductance and resistance are determined by the parameters of the components selected during circuit design and packaging. Usually, the width of the pulse signal is controlled by the capacitance value of the energy storage capacitor. When the parasitic inductance value of the loop is determined, the capacitance value of the energy storage capacitor increases, and the time of one current cycle increases accordingly, which can effectively reduce the reverse current in the first cycle. The final output pulse current signal is as follows: Figure 4 As shown, by Figure 4 It can be seen that the recoil current is much smaller than that of similar modules.

[0049] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A multi-channel controlled semiconductor laser module, characterized in that, include: Multi-channel drive circuit and multi-channel signal circuit, The multiple drive circuits share a common drive power supply. Each drive circuit in the multi-channel drive circuit includes an energy storage capacitor, a switch, and a semiconductor laser. The energy storage capacitors in each driving circuit are connected in parallel to form a common total energy storage capacitor, which is used to power the semiconductor laser in each driving circuit. Each signal circuit in the multi-channel signal circuit includes a signal source and a signal circuit unit. The signal circuit unit is connected to the switch in a one-to-one correspondence and is used to control the on and off of the switch. The first electrode of the semiconductor laser is connected to a common total energy storage capacitor, and the second electrode of the semiconductor laser is connected to the switch to form a conductive drive circuit.

2. The multi-channel controlled semiconductor laser module according to claim 1, characterized in that, The energy storage capacitor is connected to the shared driving power supply. When the switch is open, the driving power supply charges the energy storage capacitor, and when the switch is closed, the energy storage capacitor discharges to drive the semiconductor laser.

3. The multi-channel controlled semiconductor laser module according to claim 1, characterized in that, The capacitors, the switches, the semiconductor laser, and the pads are periodically arranged on the circuit board; and The semiconductor laser is connected to the circuit board via the pads using wire bonding.

4. The multi-channel controlled semiconductor laser module according to claim 3, characterized in that, The periodic spacing between similar components should not exceed 10mm; and The absolute value of the difference in periodic spacing between different components is no greater than 5mm.

5. The multi-channel controlled semiconductor laser module according to claim 1, characterized in that, The energy storage capacitor includes either a silicon capacitor or a chip capacitor.

6. The multi-channel controlled semiconductor laser module according to claim 5, characterized in that, The first electrode of the energy storage capacitor is encapsulated on the circuit board using surface mount technology; The second electrode of the energy storage capacitor is connected to the semiconductor laser; The second electrode of the energy storage capacitor is connected to the first electrode of the semiconductor laser via wire bonding; and The second electrode of the semiconductor laser is bonded to the pad via a lead or directly to the pad.

7. The multi-channel controlled semiconductor laser module according to claim 5, characterized in that, When the electrode area of ​​the energy storage capacitor is larger than that of the semiconductor laser, a three-dimensional packaging process is selected. The first electrode of the energy storage capacitor is encapsulated on the circuit board using surface mount technology; The second electrode of the energy storage capacitor is directly attached to the first electrode of the semiconductor laser and is directly connected by conductive solder. The second electrode of the semiconductor laser is bonded to the pad via a lead.

8. The multi-channel controlled semiconductor laser module according to any one of claims 1-7, characterized in that, The number and value of the energy storage capacitors connected in parallel in the multi-channel drive circuit can be infinitely adjusted. By precisely controlling the value of the parallel capacitors, capacitive reactance matching between the multi-channel drive circuit and the corresponding signal circuit can be completed simultaneously.

9. The multi-channel controlled semiconductor laser module according to claim 1, characterized in that, Each drive circuit in the multi-channel drive circuit includes multiple semiconductor lasers. The multiple semiconductor lasers are connected in series or in parallel to achieve the technical effect of single-channel control of multiple semiconductor lasers.

10. The multi-channel controlled semiconductor laser module according to claim 1, characterized in that, The semiconductor laser can be replaced by a component for converting pulsed electrical signals into other signals.

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