Minimizing cost of HID lamp electronic ballast

An electronic ballast is one of the most cost sensitive products of power electronics. The high cost of available high intensity discharge (HID) lamp electronic ballasts is constraining their wide usage. A possible way to minimize the cost of an HID lamp ballast is to chose an optimal ballast operating frequency at which the required amount of components and their cost are minimal. As shown in this paper the minimal cost achieved at a selected operating frequency is in the 300 kHz region. Because of acoustic resonance problem in the HID lamp operating at high frequency, special attention was devoted to solution of this problem. The following items were used for cost minimization: a modern controller chip with integrated low and high side FET drivers; control, start up, and fault protection logic; an integrated magnetic-transformer-inductor; the simplest lamp power control circuit; bus voltage ripple for frequency modulation of lamp current to suppress acoustic resonance.