Design Of High Reliability Stepping Motor Driver Chip

Along with the development of the electric vehicle industry,the demand for chips is increasing rapidly.Most domestic car companies use foreign chips as their mainstream products to obtain the stability and reliability of the vehicle’s electrical system.The stepper motor driver chip is one of the most commonly used chips in the car gauge chip,and is used in various mechanical connection occasions.However,the development time of my country’s automotive-grade chips is relatively short,the stability and reliability have not been recognized by the domestic market,and the substitutability is poor,so the research on the high reliability and stability of the car regulation chip is more and more attention.This paper analyzes the principle of stepper motor and the principle of stepper motor driver chip,and the modules that affect the stepper motor driver chip.This paper puts forward the factors affecting the reliability of the chip,and designs the reliability module circuit to improve the reliability and consistency of the chip.Based on DB Hi Tek’s BCD 0.18μm process,this paper designs the stepper motor driver chip to improve the overall circuit reliability of the stepper motor driver chip,including RS triggers,dead-time protection circuits,and curvature compensation bandgap reference circuit,RC oscillator circuit,over current protection circuit,over temperature protection circuit,under voltage protection circuit,error restart timing circuit and ESD protection circuit.A new type of RS flip-flop circuit is designed to eliminate the indeterminate state mode,so that the level shift module and logic circuit of the RS flip-flop in the stepper motor chip can work stably and correctly,and realize the stability and consistency of the circuit output.Dead time protection circuit,set the dead time 370 ns to ensure that the same side cannot be turned on at the same time.The curvature compensation bandgap reference circuit is used to provide the internal reference voltage and reference current to ensure that the internal reference voltage is stable,the influence of temperature is minimized,and it has a high power supply rejection ratio.The RC oscillator circuit provides a stable oscillation frequency for the interior,and cooperates with the counter in the chopper constant current control and error restart timing circuit to provide a stable timing time.Design an overcurrent protection circuit.When the current exceeds the peak current ±4A,the chip will be turned off to ensure that the internal power tube will fail due to the breakdown caused by overcurrent.The over-temperature protection circuit can operate stably under the conditions of-40~150℃ required by the on-board chip.When the temperature exceeds 155℃,the chip can be stably shut down.Under-voltage protection circuit,closes the internal circuit of the chip below 4.3V.The error restart timing circuit ensures that the chip can be stably powered on to restart the internal circuit of the chip after the internal environment is stable during the restart process.The ESD protection circuit ensures that the circuit can extend the conduction time in the case of electrostatic pulse,so that the discharge tube can discharge the current for a longer time,ensuring that the internal circuit can work stably.Through the design of the above reliability circuit,combined with the principle and working process of the stepping motor drive chip,the overall circuit design is completed to realize the reliability of the chip.Through the test and analysis of the designed circuit,the results meet the reliability requirements,and the overall simulation and layout drawing are carried out to complete the reliability design of the stepping motor driver chip.