Automatically brightness adjusting electronic device and brightness adjusting method thereof

An automatically brightness adjusting electronic device, comprising:

• a display unit with a display brightness;
• a sensing unit configured to sense an environmental light intensity;
• a first control unit coupled to the display unit;
• a second control unit coupled to the first control unit and the sensing unit;
• and
• a switch circuit, coupled to the display unit and switched between the first control unit and the second control unit, wherein the switch circuit comprises a double switch or a single-pole double-throw switch;
• wherein when the first control unit is in a sleep mode and the second control unit determines that the display brightness needs to be adjusted, the second control unit does not awake the first control unit to switch to an operation mode, the second control unit adjusts the display brightness via the switch circuit without via the first control unit,
• wherein whe the first control unit is in a sleep mode, the second control unit determines that a brightness range of the enviornmental light intensity and a brightness range of the display brightness are different and awakes the first control unit from the sleep mode to switch to the operation mode to adjust the display brightness through the switch circuit.

A brightness adjusting method, adapted to an electronic device, comprising:

• sensing an environmental light intensity;
• generating a brightness adjustment signal according to the environmental light intensity via a second control unit;
• adjusting a display brightness of a display unit according to the brightness adjustment signal via a first control unit through a switch circuit comprising a double switch or a single-pole double-throw switch coupled to the display unit and switched between the first control unit and the second control unit when the first control unit is in an operation mode;
• and
• when the first control unit is in a sleep mode, the second control unit determines that a brightness range of the enviornmental light intensity and a brightmess range of the display brightness are different and awakes the first control unit from the sleep mode to switch to the operation mode to adjust the display brightness through the switch circuit..