As mentioned in Section 2.2.1, the choice of ATQ_TRQ_MIN and ATQ_UL
influenecs how the control loop responds to load torque transients. This is shown in Figure 2-8 to Figure 2-11.
For all the following traces, from top to bottom: load torque, coil current, supply
current:
Figure 2-8 ATQ_TRQ_MIN =
0.6 A, ATQ_UL = 40 Figure 2-10 ATQ_TRQ_MIN =
0.93 A, ATQ_UL = 50 Figure 2-9 ATQ_TRQ_MIN =
0.74 A, ATQ_UL = 45 Figure 2-11 ATQ_TRQ_MIN =
1.2 A, ATQ_UL = 60
- In Figure 2-8, with lowest ATQ_UL, the motor current reaches ATQ_TRQ_MAX earlier than the other
settings. This setting therefore saves the least amount of power, though it has the
quickest response time for fast load torque transients.
- In Figure 2-11, the motor current takes long time to increase. This setting saves the most power,
but has the slowest response to load torque transients.