Self-oscillating buck driver for power LEDs

The self-oscillating converter is a popular circuit for cost-sensitive applications due to its simplicity and low component count. It is widely employed in mobile phone charges and as the stand-by power source in offline power supplies for data-processing equipment. However, this circuit almost was not explored for supplier Power LEDs. This paper presents a self-oscillating buck power electronics driver for supply directly Power LEDs, with no additional circuit. A simplified mathematical model of LED was used to characterize the self-oscillating converter for the power LED driver. In order to improve the performance of the proposed buck converter in this work the control of the light intensity of LEDs was done using a microcontroller to emulate PWM modulation with frequency 200 Hz. At using the converter proposed the effects of the LED manufacturing tolerances and drifts over temperature almost has no influence on the LED average current.