8.4.6.1 Half-Cycle Control and Full-Cycle Control

The estimated BEMF used to control the drive state of the motor has two zero-crosses every electrical cycle. The DRV10987 device can be configured to update the drive state either once every electrical cycle or twice for every electrical cycle. When AdjMode is programmed to 1, half-cycle adjustment is applied. The control logic is triggered at both the rising edge and falling edge. When AdjMode is programmed to 0, full-cycle adjustment is applied. The control logic is triggered only at the rising edge (see Figure 27).

Half-cycle adjustment provides a faster response when compared with full-cycle adjustment. Use half-cycle adjustment whenever the application requires operation over large dynamic loading conditions. Use the full-cycle adjustment for low-current (<1 A) applications because it offers more tolerance for current-measurement offset errors.

Figure 27. Closed-Loop Control Commutation-Adjustment Mode