System and method for providing external power on a universal serial bus

A method of providing external power on a universal serial bus, comprising:

• coupling a feedback node to an internal source node when in an off mode and when in a charge mode;
• charging an external power node from the internal source node when in the charge mode;
• and
• when the external power node is charged, entering a host mode by coupling the internal source node to the external power node, coupling the feedback node to the external power node and decoupling the feedback node from the internal source node.

An electronic device, comprising:

• an internal feedback node;
• a regulator which provides source voltage on an internal source node, wherein said regulator has an internal feedback input coupled to said internal feedback node for regulating voltage level;
• an external power node;
• and
• a universal serial bus power control circuit, comprising:
• at least one first switch which selectively couples said internal source node to said external power node when closed;
• a charge circuit which charges said external power node from said internal source node, and which selectively couples said internal feedback node to at least one of said internal source node and said external power node;
• a comparator which detects when said external power node is charged;
• and
• a controller which opens said at least one first switch when said external power node is not charged, which controls said charge circuit to charge said external power node while coupling said internal feedback node to said internal source node, and which closes said at least one first switch and couples said internal feedback node to said external power node in a host mode when said external power node is charged.