Overvoltage protection circuit and electronic device comprising the same

An overvoltage protection circuit for preventing a voltage higher than an allowable voltage value from being supplied to a predetermined to-be-protected circuit, the overvoltage protection circuit comprising:

• an input end to which a voltage is applied from outside the overvoltage protection circuit;
• a voltage drop device, whose one end is connected to the input end, for causing, when a voltage no lower than a predetermined limit voltage value is applied to both ends of the voltage drop device, a voltage drop by the predetermined limit voltage value;
• a first resistance device, connected between another end of the voltage drop device and a ground terminal, for causing a voltage drop by a value of a voltage applied to both ends of the first resistance device;
• a voltage detection integrated circuit for detecting a voltage between both the ends of the voltage drop device, and outputting a detection signal which indicates whether or not the detected voltage is higher than the allowable voltage value;
• and
• a switching device for, when the detection signal indicates that the detected voltage is no higher than the allowable voltage value, supplying the to-be-protected circuit with the voltage applied to the input end, and for, when the detection signal indicates that the detected voltage is higher than the allowable voltage value, ceasing a supply, to the to-be-protected circuit, of the voltage applied to the input end,
• wherein the predetermined limit voltage value is set to be greater than the allowable voltage value and to be no greater than a withstanding voltage of the voltage detection integrated circuit, and
• wherein a voltage value between both ends of the first resistance device when there is no electric current flowing into the voltage drop device is at least smaller than a detection error of the voltage detection integrated circuit.