... POST355287

To provide a protection while VCC is below the UVLOVCC threshold is fundamental to avoid damage to the CPU in case of failed HS MOSFETs. In fact, since the device is supplied from the 12 V bus, it is basically “blind” for any voltage below the turn-ON threshold (UVLOVCC).

A simple way to provide protection to the output in all conditions when the device is OFF consists in supplying the controller through the 5 VSB bus: 5 VSB is always present before +12 V and, in case of HS short, the LS MOSFET is driven with 5 V assuring a reliable protection of the load.