A system and method for powering a light-emitting element in an illumination device includes a DC power supply with the light-emitting element coupled across a positive output terminal and a negative output terminal of the DC power supply. A switching element is coupled between the light-emitting element and the negative output terminal. An average current value across the light-emitting element is measured each time the switching element is turned on. A control circuit generates a PWM signal having a pulse width determined based on the calculated average current value and a predetermined target value, and applies the PWM signal to drive the switching element on and off in accordance with the determined pulse width, and a current is generated across the light-emitting element.