Xenon HID Ballasts

In design of HID ballasts, the lamp current, ballast curve and efficiency and temperature range are of primary concern. The lamp current suggested for most HID ballasts is a square wave of low frequency (50-500 Hz). HID ballasts operating at this range are resistant to acoustic resonance due to high frequency current; they also give constant instant power without temperature fluctuations and flickering, and a constant current density. To avoid additional power consumption in HID ballasts, the ballast curve should be as close to ideal as possible, with a constant current flow to xenon HID lamps, both during start-up and operation. For industrial use, the temperature range can be between -40 and 70°C. This results in 94% efficiency in high power and 92% efficiency in low power HID ballasts. In case of rise in temperature, suitable protection should be provided to maintain the efficiency levels of HID ballasts. Some of the design recommendations for maintaining the efficiency and reliability of HID ballasts include using stable capacitors, avoiding electrolytic capacitors and using ferrite material and magnetic elements for temperature rise of less than 20°C.