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L6574

September 2003

■ HIGH VOLTAGE RAIL UP TO 600V

■ dV/dt IMMUNITY ± 50 V/ns IN FULL

TEMPERATURE RANGE

■ DRIVER CURRENT CAPABILITY:

250mA SOURCE

450mA SINK

■ SWITCHING TIMES 80/40ns RISE/FALL

■ WITH 1nF LOAD

■ CMOS SHUT DOWN INPUT

■ UNDER VOLTAGE LOCK OUT

■ PREHEAT AND FREQUENCY SHIFTING

TIMING

■ SENSE OP AMP FOR CLOSED LOOP

CONTROL OR PROTECTION FEATURES

■ HIGH ACCURACY CURRENT CONTROLLED

OSCILLATOR

■ INTEGRATED BOOTSTRAP DIODE

■ CLAMPING ON VS.

■ 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.

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.

SO16N DIP16

ORDERING NUMBERS:

L6574D L6574

CFL/TL BALLAST DRIVER PREHEAT AND DIMMING

BLOCK DIAGRAM

GND

REF

Imin

ING

VCO

EN1

THE

EN2

BOOT

OUT

BOOT

LOAD

H.V.

LVG

DETECTION

HVGBOOTSTRAP

DRIVER

HVG

DRIVER

LVG DRIVER

Vthpre

Ifs

PRE

REF

Imax

PRE

OP AMP

OPOUT

OPIN-

OPIN+

DEAD

TIME

DRIVING

LOGIC

CONTROL

LOGIC

Ipre

LEVEL

SHIFTER

D97IN493A

Summary of content (10 pages)

PAGE 1
L6574 CFL/TL BALLAST DRIVER PREHEAT AND DIMMING ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ HIGH VOLTAGE RAIL UP TO 600V dV/dt IMMUNITY ± 50 V/ns IN FULL TEMPERATURE RANGE DRIVER CURRENT CAPABILITY: 250mA SOURCE 450mA SINK SWITCHING TIMES 80/40ns RISE/FALL WITH 1nF LOAD CMOS SHUT DOWN INPUT UNDER VOLTAGE LOCK OUT PREHEAT AND FREQUENCY SHIFTING TIMING SENSE OP AMP FOR CLOSED LOOP CONTROL OR PROTECTION FEATURES HIGH ACCURACY CURRENT CONTROLLED OSCILLATOR INTEGRATED BOOTSTRAP DIODE CLAMPING ON VS.
PAGE 2
L6574 PIN CONNECTION (top view) CPRE 1 16 VBOOT RPRE 2 15 HVG CF 3 14 OUT RING 4 13 N.C. OPOUT 5 12 VS OPIN- 6 11 LVG OPIN+ 7 10 GND EN1 8 9 EN2 D97IN492 THERMAL DATA Symbol Rth j-amb Parameter Thermal Resistance Junction to ambient Max. DIP16 SO16N Unit 80 120 °C/W PIN DESCRIPTION N° Pin Function 1 CPRE Preheat Timing Capacitor.
PAGE 3
L6574 PIN DESCRIPTION (continued) N° Pin Function 9 EN2 Enable 2. EN2 input (active high) restarts the start-up procedure (preheating and ignition sequence). This features is useful if the lamp does not turn-on after the first ignition sequence . 10 GND Ground. 11 LVG Low Side Driver Output. This pin must be connected to the low side power MOSFET gate of the half bridge. A resistor connected between this pin and the power MOS gate can be used to reduce the peak current. 12 VS Supply Voltage.
PAGE 4
L6574 RECOMMENDED OPERATING CONDITIONS Symbol VS Parameter Value Unit 10 to VCL V -1 to VBOOT-VCL V 500 V Supply Voltage VOUT (*) High Side Reference VBOOT (*) Floating Supply Voltage (*) If the condition Vboot - Vout < 18 is guaranteed, Vout can range from -3 to 580V. ELECTRICAL CHARACTERISTCS (VS = 12V; VBOOT-VOUT = 12V; Tamb = 25°C) Symbol Pin Parameter Test Condition Min. Typ. Max. Unit Vs Turn On Threshold 9.5 10.2 10.9 V Vsuvn Vs Turn Off Threshold 7.3 8 8.
PAGE 5
L6574 ELECTRICAL CHARACTERISTCS (continued) (VS = 12V; VBOOT-VOUT = 12V; Tamb = 25°C) Symbol Pin Parameter Test Condition Min. Typ. Max. Unit Timing Section kpre 1 kfs Vthpre Pre Heat Timing constant Cpre = 330nF 1.15 1.5 1.85 s/µF Frequency Shift Timing Constant Cpre = 330nF 0.115 0.15 0.185 s/µF 3.3 3.5 3.7 V 0.
PAGE 6
L6574 Oscillator Section: A voltage controlled oscillator, with the selected frequencies fpre and fing, drives the output half bridge. Independently selected, fpre is effective during tpre and fing is effective during normal lamp burning. When working open loop, fpre and fing are the highest and lowest allowed oscillation frequencies. Closed loop control of the lamp current under normal operation can be achieved with the L6574. This is accomplished by automatic adjustment of the oscillator frequency.
PAGE 7
L6574 Figure 4. ∆f vs. RPRE, with R ING = 100kΩ Figure 1. fING vs. RING. fING (KHz) D98IN867 ∆f (KHz) D98IN870 RING=100KΩ 100 100 80 80 60 60 40 40 20 20 20 40 60 80 Figure 2. ∆f vs. RPRE, with R ING = 33kΩ ∆f (KHz) 20 100 RING(KΩ) D98IN868 40 60 80 100 RPRE(KHΩ) Figure 5. fING vs. temperature. fING (KHz) D98IN871 RING=33KΩ 80 70 60 60 40 50 20 20 40 60 80 100 RPRE(KΩ) Figure 3. ∆f vs. RPRE, with R ING = 50kΩ ∆f (KHz) D98IN869 40 -50 0 50 100 T(˚C) Figure 6.
PAGE 8
L6574 mm DIM. MIN. TYP. A a1 inch MAX. MIN. TYP. 1.75 0.1 0.25 a2 MAX. 0.069 0.004 0.009 1.6 0.063 b 0.35 0.46 0.014 0.018 b1 0.19 0.25 0.007 0.010 C 0.5 c1 45˚ (typ.) 9.8 10 0.386 0.394 E 5.8 6.2 0.228 0.244 e 1.27 0.050 e3 8.89 0.350 F (1) 3.8 4 0.150 0.157 G 4.6 5.3 0.181 0.209 L 0.4 1.27 0.016 0.050 S Weight: 0.20gr 0.020 D (1) M OUTLINE AND MECHANICAL DATA 0.62 0.024 SO16 Narrow 8˚(max.
PAGE 9
L6574 mm DIM. MIN. a1 0.51 B 0.77 TYP. inch MAX. MIN. TYP. MAX. 0.020 1.65 0.030 0.065 b 0.5 0.020 b1 0.25 0.010 D 20 0.787 E 8.5 0.335 e 2.54 0.100 e3 17.78 0.700 F 7.1 0.280 I 5.1 0.201 L OUTLINE AND MECHANICAL DATA 3.3 0.130 DIP16 Z 1.27 0.
PAGE 10
L6574 Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice.