L6574 Datasheet, PDF (1/10 Pages) STMicroelectronics – CFL/TL BALLAST DRIVER PREHEAT AND DIMMING

L6574
CFL/TL BALLAST DRIVER PREHEAT AND DIMMING
s HIGH VOLTAGE RAIL UP TO 600V
s dV/dt IMMUNITY ± 50 V/ns IN FULL
TEMPERATURE RANGE
s DRIVER CURRENT CAPABILITY:
250mA SOURCE
450mA SINK
s SWITCHING TIMES 80/40ns RISE/FALL
s WITH 1nF LOAD
s CMOS SHUT DOWN INPUT
s UNDER VOLTAGE LOCK OUT
s PREHEAT AND FREQUENCY SHIFTING
TIMING
s SENSE OP AMP FOR CLOSED LOOP
CONTROL OR PROTECTION FEATURES
s HIGH ACCURACY CURRENT CONTROLLED
OSCILLATOR
s INTEGRATED BOOTSTRAP DIODE
s CLAMPING ON VS.
s SO16, DIP 16 PACKAGES
DESCRIPTION
In order to ensure voltage ratings in excess of
600V, the L6574 is manufactured with BCD OFF
LINE technology, which makes it well suited for
lamp ballast applications.
SO16N
DIP16
ORDERING NUMBERS:
L6574D
L6574
The device is intended to drive two power MOS-
FETS, in the classical half bridge topology, ensur-
ing all the features needed to drive and properly
control a fluorescent bulb.
A dedicated timing section in the L6574 allows the
user set the necessary parameters for proper pre-
heat and ignition of the lamp.
Also, an OP AMP is available to implement closed
loop control of the lamp current during normal
lamp burning.
An integrated bootstrap section, eliminating the nor-
mally required bootstrap diode and the zener clamp-
ing on Vs, makes the L6574 well suited for low cost
applications where few additional components are
needed to build a high performance ballast.
BLOCK DIAGRAM
OPOUT
OPIN-
OPIN+
OP AMP
+
-
Imin
V_REF
R_ING
Imax
V_REF
R_PRE
VCO
Cf
V_S
UV
DETECTION
BOOTSTRAP
DRIVER
HVG
DRIVER
CONTROL
LOGIC
DEAD
TIME
Ifs Ipre
+
Vthpre
-
+
-
DRIVING
LOGIC
LEVEL
SHIFTER
V_S
LVG DRIVER
+ ^VTHE
-
+ ^VTHE
-
V_BOOT
HVG
OUT
LVG
GND
EN1
EN2
C_PRE
D97IN493A
H.V.
C_BOOT
LOAD
September 2003
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