October 2007

Rev 1

1/17

AN2590

Application note

20 W dimmable CFL ballast solution

Introduction

This application note describes the 20 W dimmable CFL ballast solution which can

completely replace incandescent lamps in formal dimming systems. The dimmer controlled

range is 20% - 100% of full light output without changing the formal triac dimmer.

Compared to the formal CFL solution, this solution not only provides energy savings, but

also higher reliability and a much longer operating life.

The solution is based on the high performance ballast driver L6574D, two of the

STD4NK50Z Zener protected SuperMESH™ Power MOSFETs, and two of the STTH1L06

turbo 2 ultra fast high voltage rectifiers.

Figure 1.

Typical dimmer

Figure 2.

Dimming CFL ballast solution

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