Over-voltage protection system and electronic device using the same

An electronic device, comprising:

• at least two working circuits comprising a first working circuit and a second working circuit;
• and
• an over-voltage protection system, comprising:
• a first over-voltage protection circuit, connected between a power supply and the first working circuit, and comprising:
• a first switch unit connected between the power supply and the first working circuit;
• and
• a first detection unit, operable to detect voltage of the power supply and to turn off the first switch unit to isolate the power supply from the first working circuit when voltage of the power supply exceeds a first predetermined voltage value;
• a second over-voltage protection circuit, connected between the first over-voltage protection circuit and the second working circuit, and comprising:
• a second switch unit, connected between the first over-voltage protection circuit and the second working circuit;
• and
• a second detection unit, operable to detect the voltage of the power supply and to turn off the second switch unit to isolate the power supply from the second working circuit when the voltage of the power supply exceeds a second predetermined voltage value and is lower than the first predetermined voltage value;
• and
• a voltage load circuit, connected to the second over-voltage protection circuit in parallel, operable to bear partial voltage of the power supply to provide necessary power to the second working circuit when the second switch unit turns off.