
D E S C R I P T I O N
K E Y F E AT U R E S
I
INTERNAL START-UP CIRCUIT
I
INTERNAL CURRENT SENSE BLANKING
I
IMPROVED MICROPOWER START-UP
CURRENT
(300μA max.)
I
CLAMPED E.A. OUTPUT FOR LOWER
TURN-ON OVERSHOOT
I
MULTIPLIER CLAMP LIMITS MAXIMUM
INPUT CURRENT
I
INTERNAL OVERVOLTAGE PROTECTION
REPLACES BUILT-IN C.S. OFFSET
I
PWM OUTPUT CLAMP LIMITS MOSFET
GATE DRIVE VOLTAGE
I
INCREASED UVLO HYSTERESIS REDUCES
START-UP TIMING
(LX1562 only)
I
LOW OPERATING CURRENT CONSUMPTION
I
INTERNAL 1.5% REFERENCE
I
TOTEM POLE OUTPUT STAGE
I
AUTOMATIC CURRENT LIMITING OF BOOST
STAGE
I
DISCONTINUOUS MODE OF OPERATION
WITH NO CURRENT GAPS
I
NO SLOPE COMPENSATION REQUIRED
The LX1562 is a second-generation
family of power factor correction
controllers using a discontinuous mode
of operation. They are optimized for
electronic ballast applications. Many
improvements have been made over
the original SG3561A controller
introduced by Silicon General Semicon-
ductor in 1992.
New features include the addition of
an internal start-up circuit eliminating
bulky external components while
allowing independent boost converter
operation. Addition of internal current
sense blanking eliminating the need for
an external R/C filter network. Internal
clamping of the error amplifier and
multiplier outputs improves turn on
overshoot characteristics and current
limiting. Special circuitry has also been
added to prevent no load runaway
conditions. And finally, output drive
clamps limiting power MOSFET gate
drive independent of supply voltage
greatly enhance the products practical
application.
Although the IC design has been
optimized for electronic ballast applica-
tions, it can also be used for power
factor correction in lower power (typ <
300W) AC-DC converters. One unique
feature of the device is encompassed
by the addition of internal logic
circuitry to detect zero crossing of the
inductor current thus maintaining the
discontinuous current mode of opera-
tion. This feature prevents large
current gaps from appearing thereby
minimizing distortion and enhancing
power factor correction.
A P P L I C AT I O N S
I
ELECTRONIC BALLAST
I
SWITCHING POWER SUPPLIES
A
VA I L A B L E
O
P T I O N S
P E R
P
A R T
#
Part #
Start-Up
Voltage
LX1562
13.1V
Hysteresis
Voltage
5.2V
PA C K A G E O R D E R I N F O R M AT I O N
Plastic DIP
8-pin
0 to 100
LX1562IM
0 to 100
LX1563IM
T
A
(°C)
LX1562IDM
LX1563IDM
M
Plastic SOIC
8-pin
DM
Note: All surface-mount packages are available in Tape & Reel.
Append the letter "T" to part number. (i.e. LX1562IDMT)
LX1563
9.8V
2.1V
P R O D U C T H I G H L I G H T
T
YPICAL
A
PPLICATION
OF
THE
LX1562
IN
AN
80W
F
LUORESCENT
L
AMP
B
ALLAST
WITH
A
CTIVE
P
OWER
F
ACTOR
C
ONTROL
V
IN
I
DET
OUT
COMP
INV
C.S.
GND
IN
L
1RF730
230V
F
5
8
7
2
1
4
6
3
E
1AC
22k
100k
W
2.2M
1%
1μF
250V
1
29k
1%
.01μF
1N4935
22μF
47
R5
0.1μF
1M
1%
100μF
400V
MR854
11k
1%
1.3
R9 620k
3x
1/4W
1N4148
AC+
AC-
1
1
1
0
450μH
61T #22AWG
7T
R10
4.7M
D5
R4
R3
L1
R1
C1
D1
D3
D2
D4
R2
C4
C3
C2
D7
R7
R8
C6
V
D6
C5
R6
Q1
Note: Thick trace on schematic shows high-frequency, high-current path in circuit.
Lead lengths must be minimized to avoid high-frequency noise problems.
S
ECOND
-G
ENERATION
P
OWER
F
ACTOR
C
ONTROLLER
P
R O D U C T I O N
D
A T A
S
H E E T
T
H E
I
N F I N I T E
P
O W E R
O F
I
N N O V A T I O N
Copyright 1996
Rev. 1.3 12/96
F O R F U RT H E R I N F O R M AT I O N C A L L ( 7 1 4 ) 8 9 8 - 8 1 2 1
11861 W
ESTERN
A
VENUE
, G
ARDEN
G
ROVE
, CA. 92841
LX1562/1563
LIN D
OC
#: 1562
1