CONTROL DEVICE

A control device controls a main switch provided in a power line and a charging switch connected in parallel with the main switch together with a limiting resistor. The control device increments a counter value if the charging switch is turned on, and decrements the counter value if a time period from when the charging switch is turned off exceeds a cooling time period. If the counter value does not exceed a threshold value, the control device switches the charging switch between off and on and turns the main switch on at a trigger signal becomes an input, and turns the main switch off at the trigger signal becomes a no-input. If the counter value exceeds the threshold value, the control device holds the main switch in an on state and the charging switch in an off state regardless of the trigger signal.