AN993

L6574 ballast driver

Doc ID 5656 Rev 10

5/27

2

L6574 ballast driver

The L6574, whose internal block diagram is shown in Figure 2, is an IC intended to drive two

power MOSFETs or IGBTs in half-bridge topology, ensuring all the features needed to

properly drive and control a fluorescent bulb. Moreover, by varying the switching frequency,

it is possible to modulate the current in the lamp and as a consequence, the output power as

well. The device is available in DIP16 and SO16N packages.

The L6574 has the following distinctive features.

●

High voltage rail up to 600 V

●

dV/dt immunity

± 50 V/ns in full temperature range

●

Driver current capability (250 mA source and 450 mA sink)

●

Switching times 80/40 ns rise fall with 1 nF load

●

CMOS shutdown input

●

Under-voltage lock-out

●

Preheat and frequency shifting timing

●

Sense operational amplifier for closed-loop control or protection features

●

High-accuracy current-controlled oscillator

●

Integrated bootstrap diode

●

Clamping on VS

●

SO16, DIP16 package.

Figure 2.

Internal block diagram of the L6574

AM01310v1

OPOUT

GND

Imin

Rign

VCO

EN1

EN2

VS

Vboot

OUT

LVG

UV

DETECTION

HVG

5

6

7

4

2

3

1

12

9

8

10

11

14

15

16

BOOTSTRAP

DRIVER

HVG

DRIVER

LVG

DRIVER

Vthpre

Ifs

Cpre

Imax

Rpre

Cf

OP AMP

+

-

OPIN-

OPIN+

DEAD

TIME

DRIVING

LOGIC

CONTROL

LOGIC

+

-

Ipre

+

-

+

-

+

-

LEVEL

SHIFTER

Cboot

LOAD