SLLSFT3 November 2025 MC121-Q1
ADVANCE INFORMATION
The overcurrent protection (OCP) feature protects the integrated power FETs on the OUTx pins from shorts to the supply (VM), ground, and between the OUTx pins. When the current through a FET stays higher than the OCP threshold (IOCP) for longer than the OCP deglitch time (tOCP) as shown in Figure 6-27, all FETs in the H-bridge are disabled (Hi-Z) and the FG/RD pin indicates the locked rotor fault according to Table 6-4. The OCP fault recovery is set by OCP_RETRY_MODE.
When OCP_RETRY_MODE is set to 0x0, MC121-Q1 starts driving the motor (from pre-start phase) after tlock_long_retry lapses as shown in Figure 6-28. tlock_long_retry is set by (LRD_LONG_RETRY_SEL x tLRD_START). When OCP_RETRY_MODE is set to 0x1, MC121-Q1 latches the fault after 3 retry attempts (retry time is set by tlock_long_retry); subsequent motor operation is possible only after a subsequent power reset or wake-up (sleep exit) to clear the fault condition.