9.3.3 FLTb

This active-low open-drain output pulls low when the TPS2475x has remained in current limit long enough for the fault timer to expire. The TPS24750 operates in latch mode while the TPS24751 operates in retry mode. In latch mode, a fault timeout disables the internal MOSFET and holds FLTb low. The fault is reset when EN is pulled low or VCC falls under UVLO. In retry mode, a fault timeout first disables the internal MOSFET, next waits sixteen cycles of TIMER charging and discharging, and finally attempts a restart. This process repeats as long as the fault persists. In retry mode, the FLTb pin is pulled low whenever the internal MOSFET is disabled by the fault timer. In a sustained fault, the FLTb waveform becomes a train of pulses. The FLTb pin does not assert if the internal MOSFET is disabled by EN, OV, overtemperature shutdown, or UVLO. This pin can be left floating when not used.