SLVSDF3F MARCH 2017 – JANUARY 2019 TPSM846C23
PGOOD is an open-drain digital active-high output signal that indicates if the output voltage is within regulation limits. A pullup resistor value between 10 kΩ and 100 kΩ to a voltage source of 5.5 V or less is required. The PGOOD window is defined by OV warning limit and UV warning limit in PCT_OV_UV_WRN_FLT_LIMITS (MFR_SPECIFIC_07) (D7h), which can be programmed through the PMBus interface, as shown in Figure 17. The PGOOD pin pulls low upon any fault condition by default. See Table 7 for the possible sources to pull down the PGOOD pin.
The PGOOD signal can be connected to the CNTL pin of another device to provide additional controlled turnon and turnoff sequencing.
The OVW or PGOOD signal trips when the FB pin is prebiased to higher than 5% above the regulation level. This level of prebias is unusual, and it is beneficial to flag a warning in this situation.
The presence of a pullup voltage at the PGOOD pin high before the TPSM846C23 device receives input power causes the PGOOD pin to be pulled above a logic-low-voltage level due to the limited pulldown capability in an un-powered condition. If this is not desired, increase the pullup resistance or reduce the external pullup-supply voltage.