Any time the output voltage falls more than a few percent, output voltage ramps up slowly. This condition, called graceful recovery from dropout in this document, differs from soft start in two important ways:
- The reference voltage is set to approximately 1% above what is needed to achieve the existing output voltage.
- If the device is set to FPWM, the device continues to operate in that mode
during the recovery from dropout. If output voltage were to suddenly be pulled
up by an external supply, the LMR36503E-Q1 can pull
down on the output. Note that all protections that are present during normal
operation are in place, preventing any catastrophic failure if output is shorted
to a high voltage or ground.
Whether output voltage falls due to high load or
low input voltage, after the condition that causes output to fall below the set
point is removed, the output climbs at the same speed as during start-up.