A new scheme of the automotive High Intensity Discharge (HID) lamp ballast systems is proposed. The proposed scheme consists of the high frequency DC-DC converter and low frequency DC-AC inverter, like the conventional HID ballast system. However, this system separates the input voltage of the ignitor from the de link voltage using auxiliary winding, which results in the use of the lower voltage rating power devices for the HID lamp ballast system, compared with the conventional system. As a result, the proposed system has a lower cost and higher efficiency. For the improvement of the efficiency, the proposed ballast controller using a microprocessor, controls the frequency to operate the DC-DC converter in the critical conduction mode. This paper presents the design and analysis of the proposed ballast and some experimental results.
