The Design Of High Current Fast Edge Narrow Pulse Generating Module

Current pulse signals are widely used in the fields of Lidar driving and discrete device testing.Compared with constant current signals,current pulses can provide higher instantaneous power to the load,and avoid the test accuracy of the load due to heat problem.The improvement of current pulse amplitude,frequency,pulse width and edge time and other parameters and the improvement of parameter adjustment range are the core contents of related research.This article focuses on the above-mentioned core content and conducts in-depth research on the following issues:(1)Research on current pulse generation technology.The current pulse is generated by using a constant current source circuit or a high-speed switch with an energy storage network.This paper studies the two schemes for generating current pulses,expounds the principle of generating current pulses;compares the performance of the current pulses generated by the two schemes on the two core parameters of amplitude and edge speed,and combines the results in this design.The generated current pulse amplitude should be able to be flexibly adjusted within a large range of 0A?5A with a resolution of 10 m A and the edge time should be less than 2ns.The two specific requirements are to determine the high-speed switch and energy storage network solution as the basic solution of this design..(2)Research on driving pulse synthesis and control technology based on GaN field effect transistors.The parameters such as the highest frequency,narrowest pulse width and edge time of the current pulse generated by the high-speed switch and the energy storage network are determined by the performance of the high-speed switch.The selection of related indicators is better than the gallium nitride field effect transistor of the traditional metal oxide field effect transistor.The high-speed switch of this design.A theoretical analysis of the influence of parasitic parameters and gate resistance in the switching process of GaN FETs is carried out to guide the design of high-speed switching drive circuits.Aiming at the requirement of adjustable current pulse frequency and pulse width,a digital pulse signal synthesis circuit based on DDS and delay line is designed.In response to the specific requirements of the GaN field effect transistor for the driving circuit,the driving pulse conditioning circuit is designed to adjust the amplitude and edge of the digital pulse signal,and simulation research is carried out to verify the relevant conclusions about parasitic inductance and gate resistance in the theoretical analysis.The correctness.(3)Current pulse amplitude adaptive adjustment circuit design: In order to ensure that the current pulse amplitude can be adjusted accurately when the system is driving different loads,the current pulse amplitude adaptive adjustment circuit is designed to detect the current pulse amplitude in real time and adjust the current according to the amplitude measurement result.Pulse amplitude.After researching and comparing the three current pulse amplitude measurement schemes,the shunt-based amplitude measurement scheme is determined,and the current pulse amplitude measurement circuit is completed with high sampling rate ADC,appropriate amplitude measurement circuit and ADC driving circuit.Through the above research and design,the system can obtain a current pulse with a maximum amplitude of 5A,a maximum frequency of 2MHz,a minimum pulse width of 25 ns,and an edge time of less than 2ns on a maximum load of 3?.The various parameter levels of the current pulse are the same as those of Newport's LDP-3830 is equivalent.