| 摘要 |
A high intensity discharge (HID) lamp output control and protection circuit comprises four comparators CA1-CA4, a timer T and a pulse width modulation IC controller P. Comparator CA1 detects blocking oscillation conditions; comparator CA2 detects whether the HID lamp is lit, comparator CA3 detects too low voltage and short circuit of the lamp; comparator CA4 detects too high voltage of the HID lamp; the timer T protects the lamp at zero load and when it is unlit; and the pulse width modulation IC controller P controls the lamp output power, starts the lamp and has a soft-start function. The circuit provides fast response, power saving, and high stability protecting functions for abnormal lamp conditions such as an aged lamp, without requiring connection to both ends of the lamp. |
