The gated (or unusual) mode of operation is selected by setting the PGOOD_MODE bit to 0 in the PGOOD_CTRL_2 register.
For the gated mode of operation, the PGOOD behaves as follows:
- PGOOD is set to active or asserted state upon exiting the OTP configuration as an initial default state.
- PGOOD status is suspended or unchanged during an 800-µs gated time period, thereby gating-off the status indication.
- During normal power-up sequencing and requested voltage changes, the PGOOD state is not changed during an 800-µs gated time period. It typically remains active or asserted for normal conditions.
- During an abnormal power-up sequencing and requested voltage changes, the PGOOD status could change to inactive or de-asserted after an 800-µs gated time period if any output voltage is outside of regulation range.
- Using the gated mode of operation could allow the PGOOD signal to initiate an immediate power shutdown sequence if the PGOOD signal is wired-OR with signal connected to the EN input. This type of circuit configuration provides a smart PORz function for processor that eliminates the need for additional components to generate PORz upon start-up and to monitor voltage levels of key voltage domains.
Each detected fault sets the correcting fault bit in the PG_FAULT register to 1. The detected fault must be cleared to continue the PGOOD monitoring. The overvoltage and thermal shutdown are cleared by writing 1 to the OVP_INT and TDIE_SD_INT interrupt bits in the INT_TOP_1 register. The regulator fault is cleared by writing 1 to the corresponding register bit in the PG_FAULT register. The interrupts can also be cleared with the VANA UVLO by toggling the input supply. An example of the PGOOD pin operation in gated mode is shown in Figure 7-8.
Figure 7-8 PGOOD Pin Operation in Gated Mode