| 摘要 |
PROBLEM TO BE SOLVED: To resolve troubles of going-out of a lamp large cyclic currents caused by delay time, with an advantage of high-frequency starting being maintained, and to light the HID lamp by an inexpensive and simple circuit constitution. SOLUTION: This electronic ballast starts the HID lamp in the high-frequency starting mode, and it operates the HID lamp in the low-frequency operating mode after the starting. In the high-frequency starting mode, the HID lamp is driven by the voltage including a high-frequency component for lighting the HID lamp, and a unipolar or bipolar offset component for maintaining the HID lamp lighted during the transition stage from the high-frequency starting mode to the low-frequency operating mode. |
