In case of a short circuit, an over-current pin for the corresponding channel is raised high. At the same time the device switches to a current limiting mode. This gives the controller the opportunity to switch off the power via the corresponding EN pin.
MIC20xx family of devices seem as a very good alternative to fuses in power supplies with microcontrollers. They come in 800mA, 1A, and 1.2A current limit versions, as well as adjustable ones. Versions with automatic circuit breaking can be found as well, which cut the power in an over-current event, instead of limiting it. Other features include thermal shutdown, and under-voltage protection.