Self Oscillating Boost CONVERTER

In this project, a self-oscillating boost converter with a blocking diode is proposed to meet the desire for simple, cost-effective, high performance and highly efficient LED drivers. As compared with traditional self-oscillating converters, the proposed converter demonstrates several appealing advantages including design simplicity, robustness, soft switching characteristics (zero voltage switching (ZVS) and zero current switching (ZCS)), tight current regulation and high efficiency over a wide range.

The control stage is implemented with a compact and low cost industry standard controller, which assumes multiple roles in switching and LED current regulation. A type III compensator with anti-windup is designed to limit the maximum LED current at startup and to achieve tight LED current regulation at steady state.

The efficiency and desired transient/steady state performances are verified with SPICE simulation and a prototype circuit, which demonstrate a maximum efficiency of 95.9% and 2.3% ripple factor for the LED current. The robustness of the proposed driver is verified under a range of power supply voltage and different numbers of LEDs at the load side. In addition, the circuit is modified to implement high efficiency PWM dimming between 5% and 95%.