20160401090559 5977

WS9931 Product Description
LED Ripple Current Elimination Controller
Description
The WS9931 is an adaptive linear current regulator to
Features

Eliminate ripple current for single stage LED driver

Without external COMP capacitor

Built-in soft-start

Max Output current is up to 300mA

Internal intelligent over temperature protection

Operating temperature range from -40℃to135℃
eliminate LED low frequency ripple current. It adopts an
adaptive control solution without additional circuit design.
It can realize the function of LED light non-filtering with
very few external components, so the system cost and
size are minimized. The WS9931 is mainly applied in bulb
lights and tube lights, especially suitable for COB (chip on
board) mode.
The operating temperature range of the WS9931 is
from -40℃to135℃.
The WS9931 is available in ESOP8 Package.
Applications

LED Tube Lights

LED Bulb Lights
Typical Application Circuit
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WS9931 Product Description
Pin Configuration and Marking Information
The WS9931 is available in ESOP-8 Package. The top marking is shown as below:
WS9931EP:Product Code
A:Product Code
X:Internal Code
BCY:Internal Code for QC
YMX:D/C
Pin Definition(Note: the heat sink at the bottom is connected to Pin 5.)
Name
Pin No.
Description
VCC
1
Power Supply
NC
2/3/4/6
NA
LEDN
5
The negative pin of LED series
GND
7/8
Ground Pin
Internal Block Diagram
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WS9931 Product Description
Ordering Information
Package
Marking
Part Number
8-Pin ESOP8,Pb-free
WS9931EP
WS9931EP
Suggestion operating range:
Symbol
parameter
value
unit
TA
Operating temperature
-50-135
℃
Absolute Maximum Ratings
Parameter
Range
unit
VIN
-0.3~6
V
LEDN
-0.3~60
V
Junction Temperature
-40~150
℃
Lead Temperature(Soldering, 10 sec.)
260
℃
Storage Temperature
-55~150
℃
Note : Stresses above those listed Absolute Maximum Ratings may cause permanent damage to the device. These are stress
ratings only, functional operation of the device should not over these or any of these absolute maximum ratings. Operating above
the absolute maximum-rated conditions may affect device reliability.
Electrical Characteristics
VIN=5V and T=25℃, unless otherwise stated.
Symbol
Parameter
Test condition
Min
Typ
Max
Unit
Supply Voltage Section
VIN
VIN clamp voltage
4.8
5
5.2
V
IOP
VIN operation current
400
500
600
uA
50
60
V
240
300
mA
The maximum voltage drop
VOVP-VO_MIN
between OVP voltage and
minimum load voltage
Io
Adaptive output current
100
Thermal Section
Thermal Regulation
TTC
Temperature
Thermal Shutdown
TSD
Temperature
Thermal Hysteresis
THYS
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Temperature
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120
℃
135
℃
18
℃
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WS9931 Product Description
Application Information
The typical value of the startup current is 500uA, and
The WS9931 is an adaptive linear current regulator to
the start-up resistor can be calculated by the equation:
eliminate LED low frequency ripple current. It adopts adaptive
RST 
control method and integrates MOS and current sense resistor
VO  VIN _ MAX
to eliminate ripple current without additional electrical design.
I VIN _ TYP

VO  5.2V
500uA
Where,
The maximum output current of the WS9931 can be up to
Vo is the load voltage in practical application;
300mA, and the value of VOVP-VO_MIN should be less than 60V.
VIN_MAX is the maximum clamp voltage, about 5.2V;
IVIN_TYP is the operating current, about 500uA.
Theory of Current Ripple Removing
The WS9931 acquires the sense voltage signal through
Over Thermal Protection
sampling the output currents signal of the load, and makes the
The WS9931 has temperature regulator control. When
signals filter. Then it magnifies the error between sense voltage
the temperature goes to 120 ℃ , the temperature
signals and filter voltage signals, and outputs the signal of error
compensation is turned on to increase LED current ripple
compensation to regulate output current signals. The WS9931
and reduce the maximum voltage of LEDN. When the
drives MOSFET to transfer the LED ripple current to voltage
temperature goes to 135 ℃ , over temperature protection
ripple on MOSFET, and ensures the constant voltage across
starts, and the MOSFET will be in On-State all the time
LED string and the current flow through LED string, thus
without suppresses function.
eliminating ripple current.
PCB Layouts
The following advices should be followed in WS9931
Start Up
The WS9931 integrates soft-start function and is supplied
by the preceding stage system. When VVIN rises up over 5V, the
WS9931 starts to work. At first, it has 350ms blanking time
without current filter function to build up stable reference
internally. Then the LED ripple current is decreased by WS9931
gradually.
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PCB layout:
IC Layout : The IC should be away from heating
devices, such as driver MOSFET, freewheeling diodes,
inductor and so on.
LEDN Pin:To increase the copper area of LEDN pin or
to connect to other NC pins for better thermal dissipation.
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WS9931 Product Description
Package Information
ESOP8 Package Outline Dimensions
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Dimensions in Millimeters
Symbol
Dimensions in Inches
Min
Max
Min
Max
A
1.350
1.750
0.053
0.069
A1
0.050
0.150
0.004
0.010
A2
1.350
1.550
0.053
0.061
b
0.330
0.510
0.013
0.020
c
0.170
0.250
0.006
0.010
D
4.700
5.100
0.185
0.200
D1
3.202
3.402
0.126
0.134
E
3.800
4.000
0.150
0.157
E1
5.800
6.200
0.228
0.244
E2
2.313
2.513
0.091
0.099
e
1.270(BSC)
0.050(BSC)
L
0.400
1.270
0.016
0.050
θ
0°
8°
0°
8°
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WS9931 Product Description
NOTE:
1.We strongly recommend customers check carefully on the trademark when buying our product, if there is any
question, please don't be hesitate to contact us.
2.Please do not exceed the absolute maximum ratings of the device when circuit designing.
3.Winsemi Microelectronics Co., Ltd reserved the right to make changes in this specification sheet and is
subject to change without prior notice.
CONTACT:
Winsemi Microelectronics Co., Ltd.
ADD: Room 1002, East, Phase 2, HighTech Plaza,Tian-An Cyber Park,Chegongmiao, FuTian, Shenzhen, P.R.
China
Post Code : 518040
Tel : +86-755-8250 6288
FAX : +86-755-8250 6299
Web Site : www.winsemi.com
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