IMPROVED TEMPERATURE PROFILE FOR EXTERNAL HEATING

An aerosol-generating device for generating an aerosol from an aerosol-forming substrate during a usage session is provided, the device including: a timer; a heater assembly including a heater element to heat the substrate; a power supply to supply power to the heater assembly; and a controller, at least a portion of the usage session being divided into n sequential time intervals, the controller limiting power supplied to the heater assembly during any or each of the n sequential time intervals such that a threshold energy for that time interval is not exceeded, the controller monitoring a cumulative amount of energy supplied from the start of an nth sequential time interval, and limiting power supplied to the heater assembly until an end of the nth sequential time interval if the cumulative amount of energy supplied from the start of the nth time interval equals the threshold energy for that time interval.