The external POWERGOOD terminal indicates if the outputs of the SMPS are correct or not (Figure 6-4). Either voltage and current monitoring or a current monitoring only can be selected for POWERGOOD indication. This selection is common for all SMPSs in the SMPS_POWERGOOD_MASK2 .POWERGOOD_TYPE_SELECT bit register. When both voltage and current are monitored, POWERGOOD signal active (polarity is programmable) indicates that all SMPS outputs are within certain percentage, VSMPSPG, of the programmed value and that load current is below ILIM.
All POWERGOOD sources can be masked in the SMPS_POWERGOOD_MASK1 and SMPS_POWERGOOD_MASK2 registers. By default, only the SMPS12 rail (or SMPS123 rail if in triple phase) is monitored. When an SMPS is disabled, it should be masked to prevent it forcing POWERGOOD inactive. When SMPS voltage is transitioning from one target voltage to another due to DVS command, voltage monitoring is internally masked and POWERGOOD is not impacted.
It is also possible to include in POWERGOOD the GPADC result for SMPS output current monitoring by setting SMPS_COMPMODE = 1. Only one SMPS can be monitored by the GPADC channel at the time.
The POWERGOOD function can also be used for monitoring an external SMPS is at the correct output level and the load is lower than the current limit; indication is through the GPIO_7 terminal.
All POWERGOOD sources can be masked in SMPS_POWERGOOD_MASK1 and
The current monitor on multi-phase rails (such as SMPS12, SMPS123, or SMPS45) may cause POWERGOOD to change to a low level (with default polarity) when transitioning from multi-phase operation to single phase operation. TI recommends masking the multi-phase rails as a POWERGOOD source, using SMPS_POWERGOOD_MASK1, or debouncing the POWERGOOD signal if this POWERGOOD toggle is not desired in the application design.