A vertical laser driver circuit for adjusting a voltage-controlled multiplexing switch

Abstract

The application discloses a vertical laser driving circuit for adjusting a voltage-controlled multi-way selection switch, comprising a multi-way laser emitter, a multi-way selection switch, a current monitor, an adjustable voltage generator and a programmable array logic device; the programmable array logic device is connected with the current monitor, the current monitor measures the charging capacity change of an energy storage capacitor on each laser channel, controls the adjustable voltage generator to generate a corresponding compensation voltage, triggers a gallium nitride switch through the multi-way selection switch and a gallium nitride driving circuit to make the multi-way laser emitter emit stable laser, and ensures the working stability.

Description

Technical Field

[0001] This invention relates to a vertical laser driving circuit, and more particularly to a vertical laser driving circuit that adjusts voltage to control a multiplexer switch. Background Technology

[0002] Some existing VCSEL driver circuits are single-channel, lacking control circuits for fine-tuning the voltage of individual laser emitters. Others are multi-channel, with multiple laser emitters arranged in an array via integrated circuits (e.g., some arrays have 28 laser emitter channels). Because the distance between the circuit and the gallium nitride switch varies in each channel, slight differences in line resistance lead to inconsistent charging of the energy storage capacitors for each laser emitter. This unstable charging results in inconsistent emission and brightness across the vertical laser channels, causing detection errors. Furthermore, existing VCSEL driver circuits lack voltage and current feedback correction circuits, preventing precise voltage adjustment for each laser emitter to ensure uniform overall emission and improve laser reliability.

[0003] A similar driving circuit in the same technical field, such as application number CN202210988702, entitled "A High-Speed ​​Driving Circuit for LiDAR, including a signal processing circuit, a delay circuit, a driving circuit, and an execution circuit," cannot detect and adjust the voltage of each laser emitter in real time, thus failing to solve the aforementioned problems. Summary of the Invention

[0004] To overcome the problems of existing technologies, this invention designs a vertical laser driving circuit that adjusts the voltage to control a multiplexer switch. It detects the change in charge on each laser emitter channel, provides feedback to adjust the voltage, ensures stable light emission, and improves the reliability of the laser.

[0005] This invention provides a vertical laser driver circuit with an adjustable voltage-controlled multiplexer, comprising multiple laser emitters connected to a programmable array logic unit (FPGA) via a multiplexer, a current monitor, and an adjustable voltage generator. The FPGA is connected to the current monitor to measure the charge change of the energy storage capacitor on each laser channel, and controls the adjustable voltage generator to generate a corresponding compensation voltage. The multiplexer and the gallium nitride (GaN) driver circuit trigger the GaN switch to enable the multiple laser emitters to emit stable laser light.

[0006] Furthermore, multiple laser emitters are arranged in an array circuit, with each laser emitter including a laser emitting head and a corresponding energy storage capacitor.

[0007] Furthermore, the current monitor is connected to a current sensor, and each laser emitter channel is connected to the current sensor. The current monitor can monitor the changes in the charging amount of the energy storage capacitor on each laser channel in real time.

[0008] Furthermore, the vertical laser driving circuit also includes a voltage monitoring circuit, which is an analog-to-digital converter (ADC) inside the programmable array logic unit (FPGA) for collecting the output voltage of multiple laser emitters and feeding it back to the adjustable voltage generator for unified correction and adjustment.

[0009] The adjustable voltage generator produces a corresponding compensation voltage to the energy storage capacitor of each laser emitter, so that each laser emitter emits a uniform and stable laser.

[0010] The advantages of the invented solution are:

[0011] (1) A current monitor and an adjustable voltage generator were added to the vertical laser drive circuit to form a current feedback inspection mechanism. This mechanism can detect changes in the charging amount of each laser emitter channel, thereby controlling the adjustable voltage generator to correct the voltage and current of each channel, ensuring the overall laser emitter's light emission stability and improving the laser's working reliability.

[0012] (2) The analog-to-digital conversion circuit inside the programmable array logic unit is also used as a voltage monitoring circuit to collect the output voltage of the multi-channel laser emitter and feed it back to the adjustable voltage generator to improve the comprehensive monitoring capability and make the circuit feedback control more accurate.

[0013] (3) The driving circuit of the present invention has a simple and practical structure, high integration, and fully utilizes the function of the programmable array logic device (FPGA). Applying the vertical laser driving circuit of the present invention to automotive lidar improves the accuracy and safety of autonomous driving. Attached Figure Description

[0014] Figure 1 This is a schematic diagram showing the functional module connections of the vertical laser driving circuit of the present invention.

[0015] Figure 2 This is a schematic diagram showing the connection between a multi-channel laser emitter and a gallium nitride switch chip.

[0016] Figure 3 This is a schematic diagram of the adjustable voltage generator circuit connection in the vertical laser driving circuit of the present invention.

[0017] Figure 4 This is a schematic diagram of the current monitor circuit connection in the vertical laser driving circuit of the present invention.

[0018] Figure 5This is a schematic diagram of the voltage monitor circuit connection in the vertical laser driving circuit of the present invention.

[0019] Figure 6 This is a schematic diagram of the multiplexer switch circuit connection in the vertical laser driver circuit of the present invention. Detailed Implementation

[0020] The technical solutions in the embodiments of the invention will now be clearly and completely described with reference to the accompanying drawings.

[0021] See Figure 1-6 This invention provides a vertical laser driving circuit with an adjustable voltage-controlled multiplexer, comprising multiple laser emitters connected to a programmable array logic unit (FPGA) via a multiplexer, a current monitor, and an adjustable voltage generator. The current monitor is connected to a current sensor, and each laser emitter channel is connected to the current sensor. The current monitor monitors the charging amount of the energy storage capacitor on each laser channel in real time and feeds it back to the FPGA to control the adjustable voltage generator to generate a corresponding compensation voltage. The multiplexer and gallium nitride (GaN) driving circuit trigger the GaN switch to make the multiple laser emitters emit stable laser light.

[0022] Multiple laser emitters are arranged in an array circuit, each laser emitter including a laser emitting head and a corresponding energy storage capacitor. For example... Figure 2 As shown, for example, 56 laser emitters are arranged in arrays 1 and 2, with each array having 28 laser emitters. Laser emitter A (numbered 1) is farther from the gallium nitride (GaN) switch chip, while laser emitter B (numbered 56) is closer. The wire lengths differ. If there is no current feedback correction drive circuit, the instantaneous discharge current of the energy storage capacitor in laser emitter A might be 15A, while in laser emitter B it might be 18A. This would lead to inconsistent instantaneous discharge amounts for each capacitor, resulting in inconsistent brightness for each laser emitter and affecting the accuracy of laser measurements. When the vertical laser drive circuit of this invention is applied, the charge of the energy storage capacitor in each laser emitter can be monitored in real time, and the adjustable voltage generator can be controlled to produce a corresponding compensation voltage, ensuring consistent discharge amounts for each energy storage capacitor and consistent brightness for each laser emitter, thus improving the working stability of the laser.

[0023] As one specific implementation method, see Figure 3The specific circuit of the adjustable voltage generator uses a programmable array logic device (FPGA) to control the on / off state of resistors R9A, R9B...R9N to control the output voltage LASER_VBUS of each laser emitter. The control principle is as follows: the output voltage LASER_VBUS of each laser emitter is read from the feedback voltage at the FB pin, compared with the internal reference voltage of the adjustable voltage generator, and then fed back to LASER_VBUS. When the value of resistor R9A, which is connected in parallel to R9, is adjusted, the output voltage of the first laser emitter can be adjusted. Similarly, when only resistor R9B, which is connected in parallel to R9, is adjusted, the output voltage of the second laser emitter can be adjusted. In this way, the output voltage can be controlled.

[0024] See Figure 4 The current monitoring circuit can represent each laser transmitter channel with a load. By connecting the current sensor to the current monitor PAC1954, the operating current can be detected when the energy storage capacitor of the laser transmitter is charging, and the feedback can be centrally fed back to the programmable array logic controller for control.

[0025] like Figure 5 As shown, to better monitor voltage fluctuations, the vertical laser driving circuit also includes a voltage monitoring circuit. The voltage monitoring circuit is an analog-to-digital converter (ADC) inside the programmable array logic unit (FPGA). The output voltage LASER_VBUS is divided by resistors R82 and R83, which can be used to collect the output voltage and feed it back to the adjustable voltage generator for unified correction and adjustment.

[0026] like Figure 6 As shown, the multi-channel selector HV2918 used in the multiplexer uses a programmable array logic device (FPGA) to control the output switch, which can select the corresponding channel to be opened and input the voltage on the corresponding laser MOS tube channel.

[0027] The following describes the implementation process of a vertical laser driver circuit that uses voltage adjustment to control a multiplexer switch:

[0028] 1) The programmable array logic device (FPGA) controls its own output pins (I / O) to connect to the discharge switch, thereby discharging the energy storage capacitors of all laser emitters.

[0029] 2) The programmable array logic device (FPGA) selects the output voltage and establishes the voltage of each laser emitter by sending output pins (I / O) to the adjustable voltage generator.

[0030] 3) Following the program design sequence, the programmable array logic (FPGA) turns on the current monitor via the communication pin (SPI) to begin real-time detection of current changes.

[0031] 4) The programmable array logic (FPGA) inputs commands through the communication pin (SPI) to open the switch channel that needs to be driven, charge the energy storage capacitor of the specified laser emitter, detect the current or voltage, calculate the energy to compensate for the charging, and then turn off the switch.

[0032] 5) The programmable array logic (FPGA) controls the gallium nitride driver circuit (GAN Driver) to trigger the gallium nitride switch so that the vertical laser (VCSEL) emits laser light.

[0033] The above describes the control process for one channel of the laser emitter. Next, multiple channels can be opened sequentially to control the overall laser emitter and ensure consistent and stable overall brightness.

[0034] The driving circuit of this invention forms a voltage and current feedback check mechanism, which can detect the current change of each laser emitter channel, thereby controlling the adjustable voltage generator to correct the power of each channel, ensuring the overall laser emitter's light emission stability and improving the laser's operational reliability.

Claims

1. A vertical laser driving circuit for adjusting voltage to control a multiplexer switch, characterized in that: The system includes a multi-channel laser emitter connected to a programmable array logic unit via a multiplexer, a current monitor, and an adjustable voltage generator. The programmable array logic unit is connected to the current monitor to measure the charge change of the energy storage capacitor on each laser channel, control the adjustable voltage generator to generate a corresponding compensation voltage, and trigger the gallium nitride switch through the multiplexer and gallium nitride drive circuit to make the multi-channel laser emitter emit stable laser light. The current monitor is connected to a current sensor, and each laser emitter channel is connected to the current sensor. The current monitor monitors the changes in the charging amount of the energy storage capacitor on each laser channel in real time.

2. The vertical laser driving circuit for adjusting voltage to control a multiplexer switch according to claim 1, characterized in that: Multiple laser emitters are arranged in an array circuit, with each laser emitter including a laser emitting head and a corresponding energy storage capacitor.

3. A vertical laser driving circuit for adjusting voltage to control a multiplexer switch according to claim 1 or 2, characterized in that: It also includes a voltage monitoring circuit, which is an analog-to-digital converter circuit inside the programmable array logic unit, used to collect the output voltage of the multiple laser emitters and feed it back to the adjustable voltage generator.

4. The vertical laser driving circuit for adjusting voltage to control a multiplexer switch according to claim 1, characterized in that: The adjustable voltage generator produces a corresponding compensation voltage to the energy storage capacitor of each laser emitter, enabling each laser emitter to emit a stable laser beam.

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