JW1237A
Adaptive 100/120Hz Current Ripple Remover
With High Voltage MOSFET Integrated
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DESCRIPTION
FEATURES
Adaptive 100/120Hz current ripple remover
60V high voltage NMOSFET integrated
Built-in zener diode for input voltage
clamping
VG output voltage high to 10V
Programmable amplitude of LED current
ripple
Programmable maximum cathode voltage of
LED
Programmable maximum LED current
Short protection
Over temperature protection
ESOP8 Package
APPLICATIONS
LED lighting
TYPICAL APPLICATION
JW1237A Rev.0.1
JoulWatt Proprietary Information. Patent Protected.
Unauthorized Photocopy and Duplication Prohibited.
℃
℃
JW1237A, integrated with 60V NMOSFET, is
used to drive a LED string, and remove the
100/120Hz LED current ripple on AC/DC power
by a capacitor between VC and GND.
The adaptive technology ensures minimum power
dissipation on JW1237A while removing LED
current ripple.
JW1237A clamps the input voltage on VIN pin to
31V. Only one resistor is needed when the output
voltage of AC/DC power is higher than 31V.
JW1237A allows user to setup maximum LED
current by the sensing resistor between VS pin
and GND, which protects JW1237A from being
damaged when LED short connected or hot-plug.
By sensing the voltage of LED-pin via a resistor
between LED- pin and VLMT pin, JW1237A
allows users to setup the maximum cathode
voltage of LED string, which could help limit the
power dissipation on chip.
It is considered that LED is shorted when the
cathode voltage of LED-is higher than short
connecting threshold and remains over 180us
JW1237A shuts down when LED is shorted and
recovers after 12mS.
JW1237A provides over thermal protection. When
the temperature of JW1237A exceed 147 , OTP
is trigged.JW1237Ashuts down until the
temperature decrease to 122 .
1
JW1237A
ORDER INFORMATION
TOP
LEAD FREE FINISH
JW1237AESOP#PBF
TAPE AND REEL
JW1237AESOP#TRPBF
PACKAGE
MARKING
ESOP8
JW1237A
JoulWatt
Note
PIN CONFIGURATION
TOP VIEW
VLMT
VS
NC
LED-
1
2
8
7
VIN
VC
GND
VG
0
3
6
LED-
4
5
ESOP8
VIN clamp voltage.............................................................................................................................. 31V
VG ................................................................................................................................................... 20V
VS, VC, VLMT ..................................................................................................................... -0.3V to 6V
LED-................................................................................................................................................. 60V
Junction Temperature
2)3)
................................................................................................................ 150ºC
Lead Temperature ...................................................................................................................... 260ºC
Storage Temperature ................................................................................................. -65ºC to +150ºC
RECOMMENDED OPERATING CONDITIONS
Junction Temperature (T
J
) ............................................................................................ -40ºC to 125ºC
CJ
AJ
ESOP8 ......................................................................, ................................................ 50 ...10ºC/W
1)
2)
3)
4)
Exceeding these ratings may damage the device.
The JW1237Aguarantees robust performance from -40°Cto 150°C junction temperature. The junction temperature
range specification is assured by design, characterization and correlation with statistical process controls.
The JW1237A includes thermal protection that is intended to protect the device in overload conditions. Thermal
protection is active when junction temperature exceeds the maximum operating junction temperature. Continuous
operation over the specified absolute maximum operating junction temperature may damage the device.
Measured on JESD51-7, 4-layer PCB.
JW1237A Rev.0.1
：
：
：
：
Note
JoulWatt Proprietary Information. Patent Protected.
Unauthorized Photocopy and Duplication Prohibited.
）4
）4
）4
THERMAL PERFORMANCE
）1
）1
）1
）1
ABSOLUTE MAXIMUM RATING
：
θ
θ
2
JW1237A
ELECTRICAL CHARACTERISTICS
VIN = 18V, TA = 25ºC, unless otherwise stated.
Item
VIN clamp voltage
VIN operation current
VIN startup voltage threshold
VIN UVLO threshold
Maximum VG output voltage
VC startup current
VLMT reference voltage
JoulWatt
Symbol
V
IN_CLP
I
IN
V
IN_ST
V
IN_UVLO
V
VG
Condition
Min.
29
Typ.
32
0.3
16.5
11.5
Max.
35
0.58
18
Units
V
mA
V
V
17V<VIN<27V
0.24
15
9
VC short to GND when
0.45
startup
1.85
Drain voltage of NMOSFET
10.5
0.65
2.05
12
0.85
2.25
V
mA
V
I
VCST
V
VLMTR
NMOSFET drain voltage limit
V
D_CLP
when voltage limit is
trigged. R
LIMIT
=100K.
Drain voltage of NMOSFET
3.7
4.4
5.1
V
SHORT protection
threshold
V
TH_SHORT
when SHORT is trigged.
R
LIMIT
=100K.
5
6
7.5
V
SHORT protection delay time
5)
SHORT protection hold time
VS voltage limit
MOS R
dson
Breakdown Voltage
5)
Guaranteed by design
TSPD
TSPH
V
VS
R
dson
BV
V
gs
=10V
60
8.3
0.175
160
11.3
0.195
85
14.3
0.215
us
ms
V
m
V
JW1237A Rev.0.1
JoulWatt Proprietary Information. Patent Protected.
Unauthorized Photocopy and Duplication Prohibited.
3
JW1237A
PIN DESCRIPTION
ESOP8
Pin No.
1
2
3
4
5
6
7
8
0
(exposed PAD)
JoulWatt
Name
VLMT
VS
NC
LED-
VG
GND
VC
VIN
LED-
Description
LED- Voltage Limit and SHORT protection Programming
LED current sensing input
Not connected
Connect to the Cathode of LED string
NMOSFET GATE Cap
Ground
LED Current Ripple Programming
Power Supply
Connect to the Cathode of LED string
BLOCK DIAGRAM
JW1237A Rev.0.1
JoulWatt Proprietary Information. Patent Protected.
Unauthorized Photocopy and Duplication Prohibited.
4
JW1237A
FUNCTIONAL DESCRIPTION
JW1237A is used to drive a LED string, and
remove the 100/120HzLED current ripple on
AC/DC power.
JoulWatt
Theory of Operation
The LED string and JW1237A are both supplied
by an AC/DC current source. The LED- pin is
connected to the cathode of LED string. A
sensing resistor R
SENSE
is connected between
the VS and GND.
JW1237Atransfers the LED current ripple to
voltage ripple, and ensures the constant voltage
across LED string and the current flow through
LED string.
The scalable adaptive function of JW1237A can
regulate the cathode voltage of LED string to
minimum to improve the efficiency of the
system.
output voltage of power supply is reduced, and
the voltage drop on NMOSFET decreases.
Conversely, when NMOSFET is working in the
linear region, LED current regulation loop is
open. C
C
is discharged to reduce the V
VC
and
I
LED
, then the output voltage of power supply is
raised, and the LED current regulation loop is
close.
The Voltage of LED- Limit
The voltage ripple on LED- pin maybe very large
when the current ripple is removed, which would
bring large power dissipation on chip. The
resistor between LED-pin and VLMT pin can
setup the limit value of the voltage of LED- pin.
Current Ripple Removing
The capacitor C
C
between VC and GND is an
integration capacitor. JW1237A transform the
voltage on C
C
to a reference voltage. The
current regulator regulates the voltage on
R
SENSE
equal to the reference voltage.
The relationship between the voltage on C
C
and
R
S
is shown as following:
V
RS
= I
LED
* R
SENSE
= V
VC
/ 10
C
C
should be large enough in order to remove
the current ripple of the LED string. However,
too large capacitor may slow down the dynamic
response.
Adaptive Regulation
The voltage on C
C
is controlled by monitoring
the operation state of integrated NMOSFET.
The efficiency of system is relatively low when
NMOSFET is working in the saturation region.
C
C
is charged to raise the V
VC
and I
LED
, then the
The limit threshold is calculated as below:
V
limit
=2V + R
LMT
* 20uA
JW1237A Rev.0.1
JoulWatt Proprietary Information. Patent Protected.
Unauthorized Photocopy and Duplication Prohibited.
5
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