Lid switch in portable computers and the power management system using the same

A portable electronic apparatus, comprising:

• a base unit of the portable electronic apparatus, said base unit having a receptacle;
• a keyboard connected with said base unit;
• a memory storing data and visual information;
• a lid pivotally attached to said base unit, said lid being rotatable between an open position allowing access to said keyboard and a closed position covering said keyboard;
• a latch unit comprising a latch hook pivotally attached to said lid and protruding from said lid, said latch hook being rotatable between a first position locking said latch hook to said receptacle when said lid is moved to said closed position and a second position releasing said latch hook from said receptacle allowing said lid to be moved to said open position;
• a switch unit mounted in said base unit adjacent to said receptacle, detecting said latch hook when said lid is in said closed position, not detecting said latch hook when said lid is in said open position, transmitting a first signal when detecting said latch hook, and transmitting a second signal when not detecting said latch hook;
• and
• a control unit receiving said first and second signals from said switch unit, and responding to said first signal by first determining that a predetermined quantity of time has elapsed since receiving said first signal and then automatically starting a suspend routine and then interrupting power supplied to the portable electronic apparatus, said suspend routine comprising the step of storing said data and said visual information in said memory.

A method for controlling a power management system provided in a portable computer, comprising the sequential steps of:

• checking whether a first signal is received from a switch unit, said first signal being transmitted from said switch unit when a latch unit pivotally attached to a lid of the portable computer is in a first position locking said latch unit to a receptacle in a main body of the portable computer, said latch unit being in said first position when said lid is moved from an open lid position where said lid allows access to said main body to a closed lid position where said lid covers said main body, said lid being hingedly attached to said main body;
• when said first signal is received from said switch unit, transmitting a system interrupt signal starting a suspend routine, and then interrupting power supplied to the portable computer, said suspend routine comprising the step of writing data to a memory;
• sensing whether a second signal is received from said switch unit, said second signal being transmitted from said switch unit when said latch unit is in a second position releasing said latch unit from said receptacle, said second position of said latch unit allowing said lid to be moved to said open lid position;
• when said second signal is received from said switch unit, sensing whether the portable computer is in a power-off state where said step of writing data to said memory has not occurred, and sensing whether the portable computer is in a suspend state where said step of writing data to said memory has occurred;
• when the portable computer is in said power-off state, booting the portable computer by restoring circuits in the portable computer to a default condition and providing power to the portable computer;
• and
• when the portable computer is in said suspend state, reading said data from said memory and providing power to the portable computer.