| 摘要 |
PROBLEM TO BE SOLVED: To provide an integrated circuit equipped with ballast control, driver circuitry and power factor correction (PFC) control circuitry. SOLUTION: At the beginning of preheating, power is supplied to the load circuitry at a voltage lower than that enabling the lamp to ignite, and the PFC control circuitry increases the DC bus voltage up to its running value. For this purpose, the PFC circuitry becomes usable in compliance with the mode of the ballast control and driver circuitry. The DC bus voltage is regulated at a loop speed lower than that at the time the lamp is ramping for lighting while the lamp is running for alleviating DC bus droop. A criterion to determine whether over-current detect signals indicate an actual fault or not, is applied. For this purpose, detect signals are counted and compared with the number of faults during ignition ramping. A lamp end-of-life condition can be detected by comparing sensed voltage with upper and lower window voltages. When a lamp is off for only a short time, it can be quickly restarted without full preheating. COPYRIGHT: (C)2006,JPO&NCIPI |
