A Brushless DC Motor Driver Chip With Adaptive Synchronous Rectification

ABSTRACT

Brushless DC (BLDC) motor driver chips are widely used in household appliances, robots, automobiles, etc. The three‐phase bridge driver is a common driving structure for BLDC motors. This paper proposes a BLDC motor driver chip with an internal bridge driver using lateral double‐diffused metal‐oxide semiconductor (LDMOS). It has an adaptive synchronous rectification (SR) controller, which controls the output current of the bridge driver to regulate the speed of the BLDC motor. The SR controller is integrated in the chip, possessing the features of optimized dead time to decrease external loss caused by dead time. This work also proposes a high‐side gate driver with real‐time switch detection, which ensures the SR controller receives the work state of high‐side power LDMOS. The chip is fabricated in a 0.18 µm BCD SOI technology and adopts a QFN package. The experimental results show that the chip's continuous and peak output current are respectively 5 A and 10 A, the maximum efficiency of the chip reaches 93.4%, and the maximum power density of the whole driver module is 12 W/cm³.