BLDC Driver Design Based on SPWM and Ring Oscillator

This paper presents two methods of designing BLDC motor drives. Both are purely hardware-based and do not use high-speed control units. One is a drive circuit built using pure MOSFETs, diodes and resistors based on ring oscillator method. It is widely used in a simple application situations. The structure is relatively simple and practical, but it has startup issue, another one uses comparators and MOSFET driver chip to build a hardware circuit which based SPWM method. It is relatively complicated, but has better startup performance. The comparative analysis has been illustrated in this paper while using this two type of drivers.