摘要 |
An electronic ballast is capable of realizing high frequency lighting of a discharge lamp and switching between at least two lighting modes with different light outputs. The ballast includes a preheating circuit having a winding component connected in parallel with a main resonant circuit with a lamp current flowing therein for the discharge lamp. A constant preheating current for the lamp filaments is supplied from a secondary winding of the winding component during lighting of the discharge lamp and a path of a current flowing on a primary winding side of the winding component is switched by a switch according to the lighting mode. |