With USB power sharing function, you can use the USB port for charging your handphone/smartphone and any others, without switch on the laptop. Not all of laptops have this USB power sharing function. For the laptop that has this function, at default the function is still disable (generally). To know whether the laptop has USB power sharing function or not, and make it enable when it has: Enter to BIOS and look for options that are related to USB. Each laptop from different brand has different name for this function, USB sleep and Charge, USB Charging, USB Power Share , etc.
Tips trick about Computer & Smartphone.