A high efficiency DC/DC converter as the front-end stage of high intensity discharge lamp ballasts for automobiles

High step-up DC/DC power converters have many applications, such as the front-end stages of high intensity discharge (HID) lamp ballasts. Conventionally, DC/DC converters with coupled inductors or transformers are employed to achieve high voltage gains. However, the efficiency is poor because of the high loss associated with the leakage inductor. An active clamp circuit can increase the efficiency at the price of increasing the cost and the control complexity. This paper presents a high efficiency, high step-up DC/DC converter, which operates similarly to the counterpart with an active clamp circuit, while the proposed converter employs only a diode instead of an active switch. The efficiency of the proposed circuit can be significantly improved because the leakage energy is recovered and the switch voltage stress is much lower. A 35 W prototype as the HID ballast front-end stage experimentally verifies the proposed converter