Patent attributes
A power management circuit that controls a plurality of power circuits for generating supply voltages at least for a processor is disclosed. The circuit includes: a real time clock that generates clock signals with a predetermined frequency; a power-on terminal to which a power-on key is connected, wherein the power-on terminal receives a voltage whose level depends on whether the power-on key is pressed or not; a power-on detecting unit that monitors a voltage at the power-on terminal and asserts a start signal if it is determined using the clock signals that the power-on key is pressed and held for a predetermined time period; and a power management controller that receives a system voltage based on a battery voltage or a DC voltage from a DC power source and, upon the start signal is asserted, starts up the plurality of power circuits in a predetermined sequence using the clock signals.
