8.4.3.3 Reverse Drive

The ISD function measures the initial speed and the initial position; the DRV10983 reverse drive function acts to reverse accelerate the motor through zero speed and to continue accelerating until the closed loop threshold is reached (see Figure 14). If the reverse speed is greater than the threshold configured in RvsDrThr[1:0], then the DRV10983 waits until the motor coasts to a speed that is less than the threshold before driving the motor to reverse accelerate.

Figure 14. Reverse Drive Function

Reverse drive is suitable for applications where the load condition is light at low speed and relatively constant and where the reverse speed is low (that is, a fan motor with little friction). For other load conditions, the motor brake function provides a method for helping force a motor which is spinning in the reverse direction to stop spinning before a normal start-up sequence.