The TPS1214-Q1 features integrated charge pump UVLO feature. The voltage across BST-SRC is internally monitored. If the voltage is < V_{(BST_UVLO)} then FLT is asserted low. Both the GATE and G gate drives also get disabled in this condition turning OFF main and bypass FETs. FLT gets de-asserted and gate drivers get enabled when BST to SRC voltage rises above V_{(BST_UVLO)}.

FLT asserts low in TPS1214-Q1 when short-circuit or I²t based overcurrent or charge pump UVLO is detected.

In the safety critical designs, short-circuit protection (SCP) feature and its diagnosis (SCP_TEST) is important.

The TPS1214-Q1 also features the diagnosis of the internal short circuit protection. SCP_TEST diagnosis can be done in low power mode or active mode.

• Short-circuit protection diagnosis in active mode:

When SCP_TEST is driven low to high in active mode then, a voltage is applied internally across the SCP comparator inputs to simulate a short circuit event. The comparator output controls the gate drive (GATE) and also the FLT. If the gate drive goes low (with initially being high due to INP = High) and FLT also goes low then it indicates that the SCP is good otherwise it is to be treated as SCP feature is not functional.

• Short-circuit protection diagnosis in low power mode:

When SCP_TEST is driven low to high in low power mode then, internal short-circuit protection (SCP) comparator wakeup up in low power mode and a voltage is applied internally across the SCP comparator inputs to simulate a short circuit event. The comparator output controls the FLT. If the FLT also goes low then it indicates that the SCP is good otherwise it is to be treated as SCP feature is not functional. G drive reamins ON while SCP_TEST is pulled high. This ensures output always connected to input during diagnosis in low power mode.