| 摘要 |
Method and apparatus for operating a motor. During a commutation state current is applied to a motor while field effect transistors (FETs) are held in an enable or disable state to effect current in phases of the motor. The phases have a high FET and a low FET. Control circuitry is employed to detect back electromotive force and zero crossing (Zc) signals that indicate transition timing for the commutation states. At a transition state the current is decreased in accordance with a noninstaneous decay function and applying a pulse width modulated signal to a switching element. Alternatively, the current is decreased by enabling either all low side FETs or all high side FETs to allow the current to decay. The next commutation state is applied after the current has been reduced, avoiding negative current to be source from ground and reducing current spikes in the motor.
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