US Patent 7558974 Disk enclosure

In a detection element for the current which flows from a power source to a disk apparatus internal circuit, a plurality of resistors are incorporated such that the detection resistance for consumption current can be selected. Based on apparatus identification information from an apparatus identification unit 31 such as a current identification signal outputting circuit or an apparatus identification structure provided in a disk apparatus unit, the detection element switching circuit switches the detection resistance value of the detection element. A voltage detection circuit detects the potential difference between both terminals of the detection element. When a current control circuit detects an excessive current based on the potential difference, the current control circuit turns off a transistor (FET).