| 摘要 |
PROBLEM TO BE SOLVED: To stably perform the dimming control of a gas discharge lamp by a few components. SOLUTION: A dimming ballast control circuit to drive a ballast power switching circuit to supply a power to the gas discharge lamp, comprises a high voltage-side switch of the ballast power switching circuit, a driver circuit to drive a low voltage-side switch, a control circuit to drive a driver circuit equipped with an oscillation circuit to generate an oscillation signal so as to control the operation frequency of the ballast power switching circuit which outputs a lamp power-supplying pulse signal, and a dimming control circuit having an input. The dimming control circuit receives an AC lamp current feedback signal and a DC input voltage reference at the input, and hence the DC input voltage reference decides a desired dimming level of the lamp; and the AC lamp current feedback signal is designed to keep the brightness of the lamp at a desired dimming level. COPYRIGHT: (C)2007,JPO&INPIT |
