Abstract: A constant-power switching power supply has an inductor with an inductor current that remains in discontinuous conduction mode (DCM), where the power supply supplies and maintains constant output power to a load without measuring output parameters, by regulating charge-up time of the inductor. A method of maintaining a constant output power for a power supply being run in discontinuous conduction mode (DCM), having an inductor, includes obtaining a measured input voltage for voltage being input to the power supply, obtaining from a memory a set of values based on the measured input voltage, and driving a pulse width modulation (PWM) generator based on the set of values, the driving of the PWM generator thereby regulating a charge-up time of the inductor to correspond to the measured input voltage, whereby the regulating of the charge-up time of the inductor maintains an essentially constant power for a load.