Hi,
AFAIK a USB port supplies up to 100mA to a device or 500mA to a hub. However, 2.5" HDDs already consume up to 1A or more. So, I'm wondering how bus powered USB drive enclosures manage power? Most of the ones I've seen have a USB connector that splits into 2 plugs, which I assume draws twice the current from 2 ports. Does this equate to 200mA or 1A? Most also have an optional power plug for self-powered mode. Is plugging in both USB plugs into 2 separate ports required or is it merely a "nice to have"? If only 1 plug is needed, again, how do such enclosures manage to supply itself and the HDD with enough power with just a 100/500mA current draw from a USB port?
AFAIK a USB port supplies up to 100mA to a device or 500mA to a hub. However, 2.5" HDDs already consume up to 1A or more. So, I'm wondering how bus powered USB drive enclosures manage power? Most of the ones I've seen have a USB connector that splits into 2 plugs, which I assume draws twice the current from 2 ports. Does this equate to 200mA or 1A? Most also have an optional power plug for self-powered mode. Is plugging in both USB plugs into 2 separate ports required or is it merely a "nice to have"? If only 1 plug is needed, again, how do such enclosures manage to supply itself and the HDD with enough power with just a 100/500mA current draw from a USB port?
