The high side supply voltage for the gate driver
is monitored by an internal bootstrap UVLO comparator. This comparator monitors the
differential voltage between SWx and HBx. This protection supports the two modes in
the following manner.
- If the measured voltage
drops below VTH-(BST_UV) in fPWM mode the converter stops
operation after a fixed amount of switching cycles.
- In PSM - ACM buck-boost
operation, the BOOT_UV triggers switching the converter to re-fresh the
boot strap voltage. If the initiated switching does not bring up the BOOT_UV
after the fixed amount of re-fresh cycles the BOOT_UV protection deactivates
the converter operation.