An electronic smoking device comprises a housing accommodating a battery (10) as an electric power source powering an electrically heatable atomizer comprising an electric heater (22) and adapted to atomize a liquid supplied from a reservoir to provide an aerosol exiting from the atomizer. The heater (22) of the atomizer is controlled by means of control electronics (14). A puff detector (18) indicates an aerosol inhaling puff to the control electronics (14). The control electronics (14) operates, for a puff, the heater (22) of the atomizer with a pre-determined level of electric power. Preferably, the electronic smoking device comprises a voltage sensor (34) measuring the battery voltage, wherein the control electronics (14) distributes the pre-determined level of electric power, for a puff, by pulse width modulation, based on the battery voltage measured by the voltage sensor (34).