Design Of Fast Micro Resistance Measuring Instrument Of PCB Based On FPGA

According to actual needs of PCB flying probe testing, need to design a high precision fast micro resistance measuring instrument.This paper discusses in detail the work flow of existing Flying Probe Tester, and the key factors of restricting its speed, and in view of these factors, and designed a new system architecture of flying probe tester, and show it’s high performance in the practical.When measuring micro resistance, the signals after conversion is very weak, for get the useful signal from he noise, weak signal detection requires careful comprehensive analysis. In order to extract signals from low signal-to-noise ratio, respectively, from the theoretical analysis and the simulation feasibility of analog circuit and digital signal processing of the two methods. They are based on the analysis of noise source and characteristics, this design also focus on the analysis of the sources of noise.This paper proposed a fast method of micro resistance measurement based on FPGA.The whole system consists of hardware system and software system, the design of constant current source, the hardware system design including amplifier, filter circuit design and the measured voltage of positive and negative test circuit; software system is mainly completed in the fly needle control card, mainly FPGA algorithm based on LMS algorithm, and IPC communication Socket program.Proved by the experiment, the measurement of plate can be measured PCB fast micro resistance and upload the IPC data fastly, and the measurement precision and repeatability precision is high.