A loss-of-GND detection circuit monitors the voltage difference between the power-ground pins (PGNDx) of the switched-mode regulator and the analog ground pin (AGND). If the voltage difference is either less than the V_{GLTH_LOW} or greater than the V_{GLTH_HIGH}, the related switched-mode regulator is disabled and cannot be enabled again as long as the condition is still present. The device state after a loss-of-GND detection is determined by the device configuration.

In case of a loss-of-PGND event on the BUCK1 regulator, the following occurs for the bit settings listed as follows:

• If the BUCK1_PGND_LOSS_OFF_EN bit is set to 1b the following occurs:
  • The BUCK1 regulator, BUCK2 regulator, and BOOST converter are disabled with activated internal resistor discharge.
  • The BUCK1_PGND_LOSS status bit is set.
  • The device goes into the OFF state.
  • The BUCK1 PGND-loss bit is latched in the Analog_Latch.
• If the BUCK1_PGND_LOSS_OFF_EN bit is set to 0b the following occurs:
  • The BUCK1 regulator, BUCK2 regulator, and BOOST converter are disabled without activating internal resistive discharge.
  • The BUCK1_PGND_LOSS status bit is set.
  • The BUCK2_EN and BOOST_EN control bits are cleared.
  • The device goes into the SAFE state.
  • The device error counter increments.
  • An interrupt to the system MCU is generated (driving the ENDRV/nIRQ pin low).
    Note: Because at least one undervoltage event of the three regulators should be configured as a global RESET condition, the device eventually goes into to the RESET state as the regulator outputs discharge to less than its UV-threshold levels. When the device is in the RESET state, the BUCK1 regulator is automatically enabled again if the BUCK1 loss-of-GND event is no longer detected.

In case of a loss-of-PGND event for the BUCK2 regulator the following occurs:

• The BUCK2 regulator is disabled without activating internal resistive discharge.
• The BUCK2_EN control bit is cleared.
• The BUCK2_PGND_LOSS status bit is set.
• The device goes into the SAFE state.
• The device error counter increments.
• An interrupt to the system MCU is generated (driving the ENDRV/nIRQ pin low).
• If the BUCK2 undervoltage event is configured as a global RESET state condition (the
  BUCK2_UV_RST_EN bit is set to 1b), the device goes into the RESET state as the V_BUCK2 output voltage discharges to less than its UV-threshold level.
• If the BUCK2 undervoltage event is not configured as a global RESET state condition (the
  BUCK2_UV_RST_EN bit is set to 0b), the device does not change the state. The system MCU can try to enable the BUCK2 regulator by setting the BUCK2_EN control bit.

In case of a loss-of-PGND event on the BOOST converter the following occurs:

• The BOOST converter is disabled.
• The BOOST_EN control bit is cleared.
• The BOOST_PGND_LOSS status bit is set.
• If the BOOST undervoltage event is configured as a global RESET condition (the
  BOOST_UV_RST_EN bit is set to 1b), the device goes into the RESET state as the V_BOOST output voltage discharges to less than its UV-threshold level.
• If the BOOST undervoltage event is not configured as a global RESET condition (the
  BOOST_UV_RST_EN bit is set to 0b), the device stays in the current state. The system MCU can try to enable the BOOST converter by setting the BOOST_EN control bit.