At present, and the development direction of electronic ballasts tends in the integration and miniaturization, increasingly high demand for electronic ballast, power requirements low, perfect protection, small volume, dragging multiple lamps, high power factor, low harmonic, drag long service life of the lamp tube. If this program is too much self-excited components based on the difference and consistency. Hence the active filter chip it excited lines, using ST l6574 and chip L6561 design electronic ballast 120V 2 x series 28w dragging one second it excitation type active filter this year by the end of July successfully through the UL, FCC certification.
　　The advantages of this ballast for:
　　1, high voltage isolation function (to 600V), which can save drive pipe of a transformer, reducing the volume of ballast; 

　　2, under voltage lockout, can avoid the ballast for low voltage in a receiving mode caused by the damage of the ballast; 

　　3, preheat time and frequency can be set, through a resistor and a capacitor can be accurate determine preheating current and preheating time, protect the ballast in the mass production of preheating current and preheating time consistency. In 

　　4, high precision pressure controlled oscillator, to ensure the normal working frequency consistency, to avoid the self excitation magnetic driven magnetic ring of discrete caused by the power deviation. 

　　5, abnormal protection, when the applied voltage is higher than the chip set voltage value and the pulse width is greater than 200ns, the ballast into protection mode. This protection mode can avoid error protection, the light and the moment of starting moment of some external clutter caused by. Protected by this model can complete all kinds of abnormal state required by the IEC standard. Number 

　　6, greatly reducing components, reducing the volume of small towns is, due to the drive power tube pressure control type MOS tube, and not the self-excited current control triode, so it can be drag one or a plurality of lamp tubes without adjustment of the ballast driven part of the parameters of the components.