A system and method for monitoring energy use in an electronic device. In one embodiment, an energy monitoring system includes a processor and an energy monitor module. The energy monitor module includes instructions that when executed cause the processor to receive values of measured parameters of a pulse signal that controls the switching of energy to an energy storage device in a switch mode power supply that provides power to an electronic device. The instructions also cause the processor to determine, based on the values of measured parameters, attributes of operation of the electronic device powered by the energy source during an interval corresponding to the measured parameters. The instructions further cause the processor to generate, based on the attributes of operation, a control signal that causes the electronic device to change the loading of the power supply by the electronic device.