SLVAFF1 January 2023 DRV8452 , DRV8462
PRODUCTION DATA
This section explains how the auto-torque algorithm modifies the motor coil current according to the applied load torque to minimize the resistive losses in the system.
Table 2-2 lists the registers associated with current control.
Parameter | Description |
---|---|
ATQ_UL[7:0] ATQ_LL[7:0] |
Upper and lower boundaries of the hysteretic band within which ATQ_CNT is controlled by modifying the motor current. |
ATQ_TRQ_MIN[7:0] ATQ_TRQ_MAX[7:0] |
Programmable minimum and maximum current limit when auto-torque is enabled. |
ATQ_TRQ_DAC[7:0] | Outputs the value of motor current when auto-torque is enabled. ATQ_TRQ_DAC can vary between ATQ_TRQ_MIN and ATQ_TRQ_MAX. |
CNT_OFLW | The CNT_OFLW flag becomes 1b if ATQ_CNT is more than ATQ_UL. |
CNT_UFLW | the CNT_UFLW flag becomes 1b if ATQ_CNT is less than ATQ_LL. |
As shown in Equation 4, the ATQ_CNT parameter is proportional to the load torque and inversely proportional to the current setting of the stepper driver.
An idealized representation of this relation is shown in Figure 2-5.
The auto-torque algorithm confines the ATQ_CNT within the hysteretic band defined by the user programmable ATQ_UL and ATQ_LL parameters, by modulating the motor current, as shown in Figure 2-5.