The ISD function measures the initial speed and the initial position; the DRV10982-Q1 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 8-13). If the reverse speed is greater than the threshold configured in RvsDrThr[1:0], then the DRV10982-Q1 device waits until the motor coasts to a speed that is less than the threshold before driving the motor to reverse accelerate.

Figure 8-13 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.