一种激光雷达探测模块控制电路的设计和制作

Design and fabrication of control circuit for lidar PMT detection module

传统上使用机械旋钮调节光电倍增管(PMT)增益的方法不仅存在需要人为依据经验手动操作、准确性差等弊端,而且PMT增益易受温度影响,需要根据环境温度动态调整PMT的高压,这些局限性都不利于其在激光雷达系统中的应用。为了便于对PMT进行增益调节并保持PMT增益的稳定,设计了可用于激光雷达系统的PMT控制电路板,该电路可使用计算机实现增益调节和高压的温度自适应调节,从而精简了信号探测系统的结构与体积,提升了信号的稳定性。本工作采用内置高压电源的H10721-20型PMT,并基于STM32单片机结合数模转换器(DAC)和外围电路完成控制电路板的设计并进行实际制作。进一步对使用电位器调节的PMT和利用所提出的控制方法进行调节的PMT进行了高压稳定性的对比实验,并对使用PMT控制电路板的米散射激光雷达的性能进行了测试。实验结果表明所提出的控制方法可实现更稳定的PMT增益控制,设计的PMT控制电路板具有良好的可靠性。

The traditional method of adjusting the gain of photomultiplier tube(PMT)with mechanical knobs not only has disadvantages of manual operation based on experience and poor accuracy,but also has a disadvantage that the gain of PMT is susceptible to temperature and the high voltage of PMT needs to be dynamically adjusted according to the ambient temperature.These limitations are not conducive to its application in lidar system.In order to adjust the gain of PMT easily and keep the stability of PMT gain,the control circuit board of PMT applicable to lidar system is designed to realize gain regulation and high-voltage temperature self-adaptive adjustment by computer,thus simplifying the structure and volume of the signal detection system and improving the stability of the signal.In this work,H10721-20 type PMT with built-in high voltage power supply is used,and the corresponding control circuit board based on STM32 single chip microcomputer,digital-to-analogue converter and peripheral circuit is designed and manufactured.Further,the high voltage stability of PMT controlled by potentiometer is compared with that of PMT adjusted by the control method proposed in this work,and then the performance of Mie scattering lidar using the designed PMT control circuit board is tested.The experimental results show that the control method proposed in this work can achieve more stable PMT gain control,which indicates that the designed PMT control circuit board has good reliability.