METHOD AND APPARATUS FOR WINDOWLESS BEMF DETECTION

摘要

A zero crossing of a motor current waveform at the terminal of a brushless sensor-less multi-phase DC motor is determined without opening a non-drive period while the motor is continuously driven. A voltage level at a first threshold at the terminal of a motor is detected. At a first time, a current flow switch connected to the terminal is switched. At a second time, a voltage level at a second threshold is detected at the terminal of the motor. The zero crossing is determined between the first time and the second time and used to synchronize the driving of the motor.