Method for controlling fan speed of electronic apparatus and electronic apparatus using the same

An electronic apparatus, comprising:

• a fan;
• a power supply configured to provide an output current according to an input voltage;
• and
• a microcontroller configured to control an operation of the fan and the power supply, and configured to:
• detect the input voltage, the output current, and a working temperature related to the electronic apparatus;
• calculate a target speed of the fan according to the input voltage, the output current, and the working temperature;
• provide a speed control signal indicating the target speed to drive the fan and obtain a fan speed signal indicating an actual speed of the fan;
• and
• perform a close-loop control according to the fan speed signal to adjust the actual speed to the target speed.