What would happen to an LM2621-based boost converter if the input goes above the programmed output, then returns to normal range?
The LM2621 switches safely and smoothly between standby and normal operation when the input voltage rises above the output, then recovers. The shutdown feature will be quite smooth as well, regardless of the input voltage. When the input is above the output, the switch will stop working and the only current draw will basically be the Vdd and the comparator monitoring the output, probably about 80uA. When the input falls below the output, the LM2621 will start switching with its 70% fixed duty cycle. It is a hysteretic converter which helps make the transition smooth, but it also means that the switch will most likely not be switching all of the time with the high input voltage and low load currents.
