Datasheet L6574D, L6574 Datasheet (SGS Thomson Microelectronics)

HIGHVOLTAGERAIL UP TO 600V
dV/dt IMMUNITY ± 50 V/ns IN FULL TEM-

PERATURERANGE
DRIVER CURRENTCAPABILITY:

250mMASOURCE
450mA SINK

SWITCHING TIMES 80/40ns RISE/FALL
WITH 1nF LOAD

CMOSSHUT DOWNINPUT
UNDERVOLTAGELOCKOUT
PREHEATANDFREQUENCYSHIFTING TIMING
SENSE OP AMP FOR CLOSED LOOP CON-

TROL OR PROTECTIONFEATURES
HIGH ACCURACY CURRENT CONTROLLED

OSCILLATOR
INTEGRATEDBOOTSTRAPDIODE
CLAMPINGON V

S

.

SO16,DIP16 PACKAGE

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 ballastapplications.

The device is intended to drive two power MOS­FETS, in the classical half bridgetopology, ensur­ing all the features needed to drive and properly
controla fluorescentbulb.

A dedicated timing section in the L6574 allows
the user set the necessaryparametersfor proper
preheatand ignitionof 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
normally required bootstrap diode and the zener
clamping on Vs, makes the L6574 well suited for
low cost applications where few additional com­ponents are needed to build a high performance
ballast.

February 2000



GND

V

REF

Imin

R

ING

VCO

EN1

V

THE

V

THE

EN2

V

S

V

BOOT

OUT

C

BOOT

LOAD

H.V.

LVG

UV

DETECTION

V

S

HVGBOOTSTRAP

DRIVER

HVG

DRIVER

LVG DRIVER

Vthpre

Ifs

C

PRE

V

REF

Imax

R

PRE

Cf

OP AMP

+

-

OPOUT

OPIN-

OPIN+

DEAD

TIME

DRIVING

LOGIC

CONTROL

LOGIC

+

-

Ipre

+

-

+

-

+

-

LEVEL

SHIFTER

D97IN493A

BLOCK DIAGRAM

SO16N DIP16

ORDERING NUMBERS:

L6574D L6574

L6574

CFL/TL BALLAST DRIVER PREHEAT AND DIMMING

1/9

THERMAL DATA

Symbol Parameter DIP16 SO16N Unit

R

th j-amb

Thermal ResistanceJunction to ambient Max. 80 120 °C/W

PINS DESCRIPTION

N. Name Function

1 Cpre Preheat Timing Capacitor
2 Rpre Maximum Oscillation Frequency Setting. Low Impedence Voltage Source. See also Cf
3 Cf Oscillator Frequency Setting(see also Ring, Rpre)
4 Ring Minimum Oscillation FrequencySetting. Low Impedence Voltage Source. See also Cf
5 OPout Sense OP AMP Output. Low Impedence
6 OPin- Sense OP Amp Inverting Input. High Impedence
7 OPin+ Sense OP AMP Non Inverting InputHigh Impedence.
8 EN1 Half Bridge Enable

9 EN2 Half Bridge Enable
10 GND Ground
11 LVG Low Side Driver Output
12 Vs Supply Voltage with Internal Zener Clamp.
13 N.C. Non Connected
14 OUT High Side Driver Reference
15 HVG High Side Driver Output
16 Vboot Bootstrapped Supply Voltage

CPRE
RPRE

CF

RING

OPOUT

OPIN+

OPIN-

1

3

2

4
5
6
7 GND

V

S

LVG

N.C.

OUT

HVG

VBOOT16
15
14
13
12

10

11

D97IN492

EN1 8 EN29

PIN CONNECTION

L6574

2/9

ELECTRICALCHARACTERISTICS(VS= 12V; V

BOOT-VOUT

=12V; T

amb

=25°C)

Symbol Pin Parameter Test Condition Min. Typ. Max. Unit

Supply Voltage

V

suvp

12 VsTurn On Threshold 9.5 10.2 10.9 V

V

suvn

VsTurn Off Threshold 7.3 8 8.7 V

V

suvh

Supply Voltage Under Voltage
Hysteresys

2.2 V

V

cl

Supply Voltage Clamping 14.6 15.6 16.6 V

I

su

Start Up Current VS<V

suvn

250 µA

I

q

Quiescent Current,
fout = 60kHz, no load.

Vs > V

supv

2mA

High voltage Section

I

bootleak

16 BOOT pinleakage current V

BOOT

= 580V 5

µ

A

I

outleak

14 OUT pin Leakage Current V

OUT

= 562V 5

µ

A

High/Low Side Drivers

I

hvgso

15 High SideDriver Source Current V

HVG-VOUT

= 0 170 250 mA

I

hvgsi

15 High SideDriver Sink Current V

HVG-VBOOT

= 0 300 450 mA

I

hvgso

11 Low SideDrive Source Current VLVG-GND = 0 170 250 mA

I

lvgsi

11 Low SideDrive Source Current V

LVG-VS

= 0 300 450 mA

t

rise

15,11Low/High Side Output Rise Time C

load

= 1nF 80 120 ns

t

fall

Low/High Side Output Fall Time C

load

= 1nF 50 80 ns

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit

I

S

Supply Current(*) 25 mA

V

LVG

Low SideOutput -0.3 toVs +0.3 V

V

OUT

High SideReference -1 to VBOOT -18 V

V

HVG

High SideOutput -1 to VBOOT V

V

BOOT

Floating Supply Voltage -1 to 618 V

dV

BOOT

/dt V

BOOT

pin Slew rate (repetitive) ±50 V/ns

dV

OUT

/dt OUT pin Slew Rate (repetitive) ±50 V/ns

V

ir

Forced Input Voltage (pins Ring, Rpre) -0.3 to 5 V

V

ic

Forced Input Voltage (pins Cpre, Cf) -0.3 to 5 V

V

EN1,VEN2

Enable Input Voltage -0.3 to 5 V

I

EN1,IEN2

Enable Input Current ±3mA

V

opc

Sense Op Amp Common Mode Range -0.3 to 5 V

V

opd

Sense Op Amp DifferentialMode Range ±5V

V

opo Sense Op Amp Output Voltage (forced) 4.6 V

T

stg,Tj

Storage Temperature -40 to +150 °C

T

amb

Ambient Temperature -40 to +125 °C

(*) The device has an internal Clamping Zener between GND and the Vcc pin, it must not be suppliedby a Low Impedance VoltageSource.
Note: ESD immunity for pins14,15 and 16 is guaranteed up to 900V (Human Body Model)

RECOMMENDED OPERATING CONDITIONS

Symbol Parameter Value Unit

V

S

Supply Voltage 10 to VCL V

V

OUT

(*) High Side Reference -1 toVBOOT-VCL V

V

BOOT

(*) Floating Supply Voltage 500 V

(*) If the condition Vboot - Vout < 18 is guaranteed, Vout can range from -3 to 580V.

L6574

3/9

High/Low Side Driving Section:

High and low side driving sections provide the
proper drive to the external power MOSFET. A
high sink/sourcedrivingcurrent (450/250 mA typi­cal) ensures fast switching times when a size 4
external power MOSFET needs to be driven.

BootstrapSection:

A patented integrated bootstrap section replaces
an external bootstrap diode. This section to­gether with a bootstrap capacitor provides the
bootstrap voltage to drive the high side power
MOSFET. This function is achieved using a high
voltage DMOS driver which is driven synchro­nously with the low side externalpower MOSFET.
For a safe operation, current flow into the Vboot
pin is inhibited, even though ZVS operation may
not be ensured.

Timing Section:

To set the proper preheat time (tpre=kpre*Cpre)
for the bulb, a capacitor is connected to the Cpre
pin which is charged with a fixed current. During
tpre, the output is switching at fpre (see Oscillator
Section). When the tpre expires, the Cpre ca­pacitor is discharged and then recharged with a
different current. This sets a second time interval
tsh (0.1 times the selected preheat time tpre) dur­ing which frequency shifting from fpre to fing is
performedto ensure lamp ignition.

OscillatorSection:

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

Symbol Pin Parameter Test Condition Min. Typ. Max. Unit

Oscillator

D

C

14 Output Duty Cycle 48 50 52 %

f

ing

Minimum OutputOscillation
Frequency

CF= 470pF;
R

ing

= 50kΩ

58.2 60 61.8 kHz

f

pre

Maximum Output Oscillation
Frequency

CF= 470pF;
R

ing

= 50kΩ;

R

pre

= 47kΩ

114 120 126 kHz

V

ref

2,4 Voltage to current converters

threshold

2V

t

d

14 Dead Time between Low and High

Side Conduction

0.8 1.25 1.7

µ

s

Timing Section

k

pre

1 Pre Heat Timing constant C

pre

= 330nF 1.15 1.5 1.85 s/µF

k

fs

Frequency Shift Timing Constant C

pre

= 330nF 0.115 0.15 0.185 s/µF

V

thpre

Pre HeatTiming Comparator
Threshold

3.3 3.5 3.7 V

Sense OP AMP

l

ib

6,7 Input Biascurrent 0.1

µ

A

V

io

Input OffsetVoltage -10 10 mV

R

out

5 Ouput Resistance 200 300 Ω

I

out +

Sink OutputCurrent V

out

= 0.2V 0.5 mA

I

out

- Source Output Current V

out

= 4.5V 0.5 mA

V

ic

6,7 Common Mode Input Range -0.2 3 V

GBW Sense Op Amp Gain Band Width

Product

1MHz

Gdc DC Open Loop Gain 80 dB

Comparators

V

the

8,9 Enabling Comparators Threshold 0.56 0.6 0.64 V

V

hye

Enabling Comparators Hysteresis 20 100 mV

t

pulse

Minimum Pulselenght 200 ns

ELECTRICALCHARACTERISTICS

(Continued)

L6574

4/9

fing are the highestand 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. The OP
AMP output is fed through a resistor diode net­work to the Ring pin. See AN993.

OP AMP Section:

The integrated OP AMP offers low output imped­ance, wide bandwidth, high input impedance and
wide common mode range. It can be readily
used to implementclosed loop control (see Oscil­lator Section) of the lamp current.

EN1, EN2 Comparators:

Two CMOS comparators, with thresholds set at

0.6 V (typical) are available to implement protec­tion methods (such as overvoltage, lamp re­moval, etc.). Short pulses (>200nsec) at the
comparatorinputs are recognized.

The EN1 input (active high) forces the L6574 in
the shut down state (e.g. LVG low, HVG low, os­cillator stopped) in the event of an undervoltage
condition. Normal operatingcondition is resumed
after a power-off power-on sequence or when
EN2 input is high.

The EN2 input (active high) also restarts a pre­heat sequence(see timingdiagrams).

V

CC

LVG

HVG

EN1

V

SUVP

D97IN490

TIMING DIAGRAMS

V

CC

t

PRE

t

PREtSH

t

SH

f

PRE

f

ING

EN2

f

OUT

V

SUVP

D97IN491B

TIMING DIAGRAMS

L6574

5/9

20 40 60 80 100 R

ING

(KΩ)

20

40

60

80

100

f

ING

(KHz)

D98IN867

Figure 1. f

ING

vs. R

ING

.

20 40 60 80 100 R

PRE

(KΩ)

20

40

60

80

100

∆

f

(KHz)

D98IN869

RING=50KΩ

Figure 3. ∆f vs. R

PRE

, withR

ING

= 50kΩ

-50 0 50 100

40

50

60

70

D98IN871

T(°C)

f

ING

(KHz)

Figure 5. f

ING

vs. temperature.

20 40 60 80 100 R

PRE

(KΩ)

20

40

60

80

∆

f

(KHz)

D98IN868

RING=33KΩ

Figure 2.∆f vs. R

PRE

, withR

ING

= 33k

Ω

20 40 60 80 100 R

PRE

(KHΩ)

20

40

60

80

100

∆

f

(KHz)

D98IN870

RING=100KΩ

Figure 4. ∆f vs. R

PRE

, withR

ING

= 100kΩ

-50 0 50 100

100

110

120

130

D98IN872

T(°C)

f

PRE

(KHz)

Figure 6. f

PRE

vs. temperature.

L6574

6/9

SO16 Narrow

DIM.

mm inch

MIN. TYP. MAX. MIN. TYP. MAX.

A 1.75 0.069

a1 0.1 0.25 0.004

0.009

a2 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 0.020

c1 45°(typ.)

D (1) 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
M 0.62 0.024
S

(1) D and F do not include mold flash or protrusions. Mold flash or potrusions shall not exceed 0.15mm (.006inch).

OUTLINE AND

MECHANICAL DATA

8°(max.)

L6574

7/9

DIP16

DIM.

mm inch

MIN. TYP. MAX. MIN. TYP. MAX.

a1 0.51 0.020

B 0.77 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 3.3 0.130

Z 1.27 0.050

OUTLINE AND

MECHANICAL DATA

L6574

8/9

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L6574

9/9