| 摘要 |
A universal serial bus power control circuit including at least one first switch which selectively couples a power source node to an external power node, a comparator which detects when the external power node is charged, a feedback node for enabling voltage regulation, a charge circuit and a controller. The charge circuit charges the external power node from the power source node and selectively couples the feedback node to at least one of the power source node and the external power node. The controller opens the first switch when the external power node is not charged, controls the charge circuit to charge the external power node while coupling the feedback node to the power source node, and closes the first switch and couples the feedback node to the external power node in a host mode when the external power node is charged.
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