Matrix Voltage-withstanding Automated Test System For PTCR

Due to its special electro-thermal properties, PTC thermistor has a wide range ofapplications in appliance, automotive electronics, telecommunications and other industries.To solve the problems in the current PTC thermistor voltage-withstanding test processincluding low efficiency, unstable test process and unreliable test results. we have designeda novel voltage-withstanding automated test system based on51MCU.According to the demand of current state, further investigations are conducted in thisthesis based on the formerly achievements. The test system utilizes dual isolatedtransformers, which can test128channel samples sequentially. New sample fixture isdesigned, which is braced and propelled by cylinder, facilitating the automatic charging.Meanwhile, the upper probe board controlled by the cylinder ensures the operator to stayaway from the high-pressure environment. MCU is selected as the control chip, based onwhich the core control circuit is designed and built. The testing parameters can be setaccording to different samples and the relay-groups can carry out voltage-withstanding testfor8*16matrix PTCR samples by sequence. Every single channel contains overcurrentprotection circuit which can monitor current of each channel and response rapidly in caseof overcurrent, with a new approach of interference excision. LED matrix, corresponding tothe sample position, can show the working status of each sample and communicate with thePC，facilitating the expanding of the automatic sorting system.The practical application shows that the test system is safely and high automatic, withaccurate and reliable test results. Furthermore, the test efficiency for single chip isimproved over four times, and the test efficiency for whole machine is improved10times.