Power auto-detection apparatus

A power auto-detection apparatus applied to a power supply of a personal computer or applied to an adapter of a notebook computer, the apparatus comprising:

• a voltage stabilizing unit receiving a first voltage and an input current to provide an output voltage;
• an over-current protective unit receiving a second voltage and the input current to provide an over-current protection for the power auto-detection apparatus;
• a regulating resistor having a ground terminal and a non-ground terminal, and adjusted to determine a first current;
• a voltage regulating unit electrically connected to the non-ground terminal of the regulating resistor, and outputting a first regulating voltage and a second regulating voltage according to the first current;
• and
• a signal processing unit electrically connected to the voltage regulating unit and receiving the second voltage, and further receiving the second regulating voltage to output a power detection signal to the personal computer or the notebook computer.