Patent ID: 6507173
Filing Date: 2003-01-14
Classification: H02J

Abstract:
A power management unit (PMU) for providing power management and supply functions to a device having a battery, comprising:a substrate; a bi-directional pin coupled to said substrate and configured to serve as an input pin during a first condition and as an output pin during a second condition; a battery charge controller coupled to said substrate and said bi-directional pin, said battery charge controller having a first charge conductive path and a second charge conductive path, said first charge conductive path providing a first conditioning charge to said battery, and said second charge conductive path providing a second full charge to said battery during said first condition; an adapter detector configured to receive a signal representative of the voltage of an external device coupled to said bi-directional pin, and to provide a detector output signal representative of the presence of an adapter, said detector output signal providing a positive indication if said adapter is a continuous output adapter or said adapter is a pulse output adapter, said adapter detector coupled to said substrate; an under voltage lockout protection circuit configured to prevent start up of said PMU until the voltage of said battery is above a threshold lockout enabling level, and configured to shut down said PMU once the voltage of said battery falls below a threshold lockout disabling level, said threshold lockout disabling level set at a lower voltage than said lockout threshold enabling level, said under voltage lockout protection circuit further coupled to said substrate; a plurality of internal switches coupled to a switch conductive path, said switch conductive path further coupled to an external switch, said internal switches configured to be responsive to said external switch allowing said external switch to have multiple functions, said plurality of internal switches coupled to said substrate; and a power on reset (POR) circuit coupled to said battery, to said substrate, and to at least one low dropout voltage regulator (LDO), said POR circuit configured to provide a POR control signal to an external controller.