Patent ID: 8350408
Filing Date: 2013-01-08
Classification: H01M,H02J,Y02E

Abstract:
1. A power management circuit comprising: a first terminal connected to an external power supply; a second terminal connected to a battery; a selection circuit configured to make a comparison between a voltage supplied from the external power supply via the first terminal and a battery voltage supplied from the battery via the second terminal, and to select one from among the voltage supplied from the external power supply and the battery voltage supplied from the battery; an output terminal configured to output the voltage thus selected by the selection circuit to an external load circuit; and a DC/DC converter charging circuit configured to charge the battery using the voltage supplied from the external power supply, and wherein the power management circuit further comprises an input current detection unit configured to detect a current that flows through the first transistor, and wherein the input current detection unit comprises: and wherein the switching operation of the first transistor is controlled according to a signal output from the input current detection unit.