May 2013

DocID024443 Rev 1

1/8

www.st.com

EVAL6574B

CFL/TL ballast driver preheat and dimming demonstration board

based on the L6574

Data brief

Features



Dimmable fluorescent lamp ballast



Multiple T8 lamps application



Wide range input (85 Vac

– 265 Vac)



PF > 0.99, THD < 10%



Fault ignition protection



Lamp absence detection

Description

This design was developed to drive a TL

fluorescent lamp of up to 58 W. It is composed of

two sections: the PFC using the L6561 controller,

and the ballast based on the L6574. The

application includes a current feedback that can

be used to control the power (and, if necessary,

the dimming function) by varying the switching

frequency during normal lamp operation. The

application also features safety circuitry which

activates when an open load or faulty lamp

ignition is detected. The PFC pre-regulator allows

connection of the application to a wide input

voltage range (85 Vac to 265 Vac) providing a

Power Factor higher than 0.99 and a THD lower

than 10%.

EVAL6574B