DRIVING CONTROL DEVICE, VEHICLE-ONBOARD POWER SUPPLY SYSTEM, AND VEHICLE

A driving control device for controlling the driving of the gate of a cut-off NMOS transistor arranged to be connectable between a first power supply circuit and a second power supply circuit includes a boost circuit configured to feed a gate control voltage to the gate and a controller configured, in start-up control for the cut-off NMOS transistor, to keep the current capacity of the boost circuit during start-up at a first current capacity and, after that, to switch the current capacity of the boost circuit to a second current capacity higher than the first current capacity.