Electronic Relay Control IC Design With Overcurrent And Undervoltage Protection

Electronic relay is a kind of electronic switch which uses small current to control large current,it has the function of switching circuit,security protection and automatic regulation in circuit.At present,the over-current protection of the motor mainly includes mechanical relay and electromagnetic relay.Among them,the mechanical relay has the shortcomings of poor precision and unguaranteed reliability,while the electromagnetic relay has high reliability.But it has the disadvantages of large volume,large consumption materials and high cost due to the limit of copper's price,so the electronic relay has more advantages,such as high reliability and high precision,and the cost is lower,so it has a wider application prospect.In this paper,an IC with over-current/under-voltage's function who controlls a electronic relay for protecting motor is designed.The main work of this thesis is as follows:1.This thesis first introduces the working characteristics and driving modes of the motor,and choose a power MOS as the electronic relay,and present the IC's system design index.2.The functions of each sub-module of the IC with over-current/under-voltage's function are deduced in detail,and the whole structure is confirmed.3.Each module index of the IC with over-current/under-voltage's function who controlls a electronic relay is set up,based on 0.25 um CMOS BCD process platform of a company,simulation is carried out under cadence spectre,including power supply,voltage sampling,overcurrent protection,under-voltage protection,over-temperature protection,short circuit protection and the drive module etc.4.Finally,the whole simulation of the IC with over-current/under-voltage's function is completed,all the protection functions of the chip are verified,including over-current protection,under-voltage protection,over-temperature protection and so on.The simulation results show that the input voltage range is 9-20 V,the upper limit of overtemperature protection is 165 degrees,the overcurrent protection's current is 300 A,the short-circuit protection's current is 500 A,and the control time is 0.5s.