Page 16 of the MAX17609 datasheet (19-100228; Rev 1; 6/18) states, "In MAX17609, the reverse current-protection feature is disabled, which allows reverse current flow from the OUT to IN pins. This feature is useful in applications with inductive loads." Inductive loads, such as motors, may exhbit a back EMF where current is injected into the source. Under this condition, reverse current protection would block current traveling from OUT to IN and cause an overvoltage condition on OUT. Disabling the reverse current protection feature allows current to flow from OUT to IN; thus, providing a path for current to travel.
In all cases of MAX17609 usage, it is important to ensure that the input source of MAX17609 is capable of taking the reverse current, as the device allows reverse current.