Constant-power electronic cigarette protecting against dry-heating and controlling method thereof

A constant-power electronic cigarette protecting against dry-heating, comprising a vaporization rod and a battery rod, wherein a vaporizer is arranged inside the vaporization rod, and the vaporizer comprises a heating resistor for heating and vaporizing electronic cigarette liquid, wherein a battery, a control circuit board, and an unlock switch button are arranged inside the battery rod, wherein a starting switch is arranged inside the vaporization rod or inside the battery rod, the heating resistor is a variable resistor which has a resistance value variable depending on a change in temperature and has a positive temperature coefficient, the control circuit board is arranged with a microcontroller chip, a resistance detection unit, a constant-power output control unit, and an output feedback unit, wherein the unlock switch button and the starting switch are electrically connected with the microcontroller chip, the resistance detection unit is electrically connected with the heating resistor to detect the resistance value of the heating resistor and feed back a resistance value signal to the microcontroller chip, the output feedback unit is electrically connected with the heating resistor to detect the operating voltage of the heating resistor and send a feedback to the microcontroller chip, the constant-power output control unit is electrically connected with the microcontroller chip to receive a PWM control signal from the microcontroller chip, the constant-power output control unit is configured to generate a corresponding PWM voltage value based on the PWM control signal and output it to the heating resistor, to allow the PWM voltage value of the heating resistor to change synchronously with the resistance value of the heating resistor to provide a constant power, in such a manner that an amount of vapor that is generated during heating and vaporization of the electronic cigarette liquid by means of the heating resistor remains the same, and further the resistance value signal is compared with a preset dry-heating value by means of the microcontroller chip, and when the resistance value signal exceeds the preset dry-heating value, an output of the constant-power output control unit is cut off by means of the microcontroller chip to avoid excessively high temperature of the electronic cigarette which can result in dry-heating.