20160322025754 5844

WS9256ProductDescription
High Precision PSR Constant Current LED Driver
Features
Description

Built-in 650V Power MOSFET
The WS9256 is a high precision primary-side

Constant current control without secondary sense and
feedback and regulation controller for LED lighting, it
feedback circuit.
operates in constant current control mode and is designed

±3% LED current accuracy
to work in inductor current discontinuous conduction mode

Ultra low operating current to improve efficiency
and extremely suitable for flyback convertor under

High resistance feedback resistor to improve efficiency
universal input, the output power of system should be less

Universal input voltage
than 24W.

LED short and open circuit protection

VCC under-voltage protection
adopting primary sense and feedback control technology,

Feedback loop short circuit protection
the secondary sense and feedback circuit is eliminated.

Current sense resistor open circuit protection
The loop compensation components are also removed

Over temperature protection
while maintaining stability overall operating conditions. The

No external loop compensation component required
low component counts and low BOM cost are realized.

Available in DIP-7 package
The WS9256 integrates 650V power MOSFET. Since
Since using the proprietary high accurate current
sense method, the WS9256 realizes ±3% accuracy of LED
current along with excellent line regulation and load
Applications

LED bulb light

Other LED lighting
regulation.
The WS9256 offers rich protection functions including
LED short circuit protection, LED open circuit protection,
die
over-temperature
protection,
VCC
over
voltage
protection, VCC under voltage protection and FB short
circuit
protection.
All
the
protection
features
are
auto-recovery.
Typical Application
WINSEMI
MICROELECTRONICS
WINSEMI
MICROELECTRONICS
[email protected] Co.,Ltd.,All rightreserved.
WINSEMI
MICROELECTRONICS
WINSEMI
MICROELECTRONICS
WINSEMI
MICROELECTRONICS
1209
WS9256ProductDescription
Pin Configuration and Marking Information
WS9256 is offered in DIP7 package, as bellows:
WS9256D7P
A:Product Code
X:Internal Code
BCY:Internal Code For QC
YMX:D/C
Pin Definition
Pin No.
Pin Name
Function Description
1
GND
Ground.
2
FB
Feedback. This pin detects the output information from auxiliary winding.
3
VCC
Power suppl.
4
CS
5,6
Drain
Internal high voltage MOSFET drain.
7
NC
No connection, must be floated.
Current sense. This pin connects a current sense resistor to GND to detect
the primary current of transformer.
Internal Block Diagram
WINSEMI
MICROELECTRONICS
WINSEMI
MICROELECTRONICS
www.winsemi.com Tel : +86-755-8250 6288
WINSEMI
MICROELECTRONICS
Fax : +86-755-8250 6299
WINSEMI
MICROELECTRONICS
WINSEMI
MICROELECTRONICS
2/8
WS9256ProductDescription
Ordering Information
Package
Marking
Part Number
7-Pin DIP-7, Pb-free
WS9256D7P
WS9256D7P
Recommended Operation Conditions
Symbol
Parameter
Value
Unit
Fmax
Maximumworking frequency
100
khz
TA
Operation temperature
-20~85
℃
VCC
Power supply voltage
10~17.5
V
POUT1
Output power(Input voltage230V±15%)
<30
W
POUT2
Output power(Input voltage85V~265V)
<24
W
Absolute Maximum Ratings (Note1)
symbol
paramete
limites
unit
VCC
VCC pin input voltage
-0.3~20
V
FB
Feedback pin input voltage
-0.3~6
V
Drain
Internal MOSFET drain voltage
-0.3~650
V
CS
Current sense pin input voltage
-0.3~6
V
PDMAX
Power dissipation (note2)
0.9
W
Tjo
Operating junction temperature
-40~150
℃
θJA
Thermal resistance (Junction to Ambient)
80
℃/W
TSTG
Storage temperature range
-55~150
℃
Note 1: Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. Under
“recommended operating conditions” the device operation is assured, but some particular parameter may not be achieved.
The electrical characteristics table defines the operation range of the device, the electrical characteristics is assured on DC and
AC voltage by test program. For the parameters without minimum and maximum value in the EC table, the typical value defines
the operation range, the accuracy is not guaranteed by spec.
Note 2: The maximum power dissipation decrease if temperature rise, it is decided by TJMAX, θ JA, and environment
temperature (TA). The maximum power dissipation is the lower one between PDMAX = (TJMAX - TA)/ θJA and the number
listed in the maximum table.
WINSEMI
MICROELECTRONICS
WINSEMI
MICROELECTRONICS
www.winsemi.com Tel : +86-755-8250 6288
WINSEMI
MICROELECTRONICS
Fax : +86-755-8250 6299
WINSEMI
MICROELECTRONICS
WINSEMI
MICROELECTRONICS
3/8
WS9256ProductDescription
Electrical Characteristics (Unless otherwise specified, VCC=8V and TA =25 ℃)
Symbol
Parameter
Test condition
Min
Typ
Max
Units
4mA
17.4
18.3
19.4
V
16.1
17.1
18.1
V
8.5
9
9 .5
V
17.9
18.9
19.9
V
Supply Voltage Section
VDD_CLAMP
UVLO_on
VDD Clamping Voltage
VDD Power Supply
VDD Under Voltage
UVLO_off
Lockout
VCCover voltage
VCC_OVP
protection level
Ist
Start up current
35
uA
Iop
Operating current
152
uA
Current Sense Section
Ipp
Primary Peak Current
484
508
531
mV
TLEB
Lead Edge Blanking
500
ns
TDELAY
Shutdown Delay
200
ns
D_max
Maximum Duty Cycle
42
%
420
us
4
us
MaxmiumON time
100
us
FB voltage sense level
1
V
FeedbackInputSection
MaximumDemagnetization
Toff_max
time
MinimumDemagnetizationt
Toff_min
ime
Ton_max
Vfb
Power MOSFET
Drain-source leakage
Idss
Vgs=0V,Vds=650V
current
BVdss
Drain-source breakdown
10
650
voltage
Static drain-source
Ron
V
2.8
on-resistance
uA
3.5
Ω
Over TemperatureProtection
T_comp
WINSEMI
Thermal Regulation
147
Temperature
MICROELECTRONICS
WINSEMI
MICROELECTRONICS
www.winsemi.com Tel : +86-755-8250 6288
WINSEMI
MICROELECTRONICS
Fax : +86-755-8250 6299
WINSEMI
MICROELECTRONICS
℃
WINSEMI
MICROELECTRONICS
4/8
WS9256ProductDescription
Application Information
The ratio of FB upper resistor to lower resistor is
The WS9256 is a high performance power switch
specially designed for LED lighting, it uses the patent
recommended to about 4.0. The FB upper resistor can be
set to 300KΩ~750KΩ to improve efficiency of convertor.
constant current control technology of WINSEMI. The
WS9256 integrates a 650V power MOSFET. The accurate
Operation Switching Frequency
LED current can be realized without opto-coupler and TL431
The WS9256 is designed to work in discontinuous
feedback circuit while minimizing the external component
conduction mode and no external loop compensation
count, lowering the total bill of material cost.
component is required while maintaining stability. The
maximum duty cycle is limited to 42%. The maximum
Start Up
switching frequency should be set to less than 100KHz and
The VCC capacitor will be charged through the start-up
the minimum switching frequency should be set to more
resistor when the system is powered on, once the voltage
than 20KHz. The maximum and minimum switching
on VCC reaches the start-up threshold, the WS9256 will
frequency is limited in WS9256 to ensure the stability of
start to operate, and then the VCC is supplied by the
system.
auxiliary winding.
The switching frequency can be set by the formula:
Np 2  VLED
f 
8  Ns 2  Lp  I LED
Constant Current Control
Cycle-by-Cycle current sense is offered in WS9256, the
Where, LP is the primary winding inductance of
CS is connected to the current sense comparator, and the
voltage on CS will be compared with the internal 508mV
reference voltage, the MOSFET will be switched off when
the voltage on CS reaches the threshold. The output of the
transformer.
Protection Function
The WS9256 has several protection functions. The
comparator also includes a 500nS leading edge blanking
internal MOSFET will be shut down immediately when the
time
voltage on VCC reaches the threshold of OVP and the
The primary peak current is given by:
I P_PK
device will not recover until the protection condition is
508

( mA)
RCS
removed. A 18V zener diode is designed in the WS9256 to
prevent the chip damage from the abnormal situation.
The current in LED can be calculated by the equation:
I OUT 
I P_PK
4

The thermal protection circuitry in the WS9256 senses
the die temperature after start up, and the thermal protection
NP
NS
threshold is set to 147℃
The system will work in low consumption mode when
Where,
the output LED short circuit or open circuit is detected.
NP: primary winding turns of transformer
While the WS9256 continuous to detect output status until
NS: secondary winding turns of transformer
the LED recover to normal condition, and then the device
IP_PK: peak current in MOSFET
will be operate in normal mode.
Feedback Network
PCB Layout
The WS9256 senses the output information through the
feedback network and the FB threshold voltage is set to 1V.
WINSEMI
MICROELECTRONICS
WINSEMI
MICROELECTRONICS
www.winsemi.com Tel : +86-755-8250 6288
WINSEMI
The following rules should be followed in WS9256 PCB
layout:
MICROELECTRONICS
Fax : +86-755-8250 6299
WINSEMI
MICROELECTRONICS
WINSEMI
MICROELECTRONICS
5/8
WS9256ProductDescription
Bypass Capacitor
NC Pin
The bypass capacitor on VCC should be as close as
The NC pin must be left floating to satisfy the
possible to the VCC pin
requirement of creepage distance.
Ground Path
Drain pin
The power ground path for current sense should be
To increase the copper area of drain for thermal
short, and the power ground path should be separated from
consideration.
small signal ground path before the negative of the bulk
FB Pin
capacitor.
The feedback divider should be as close as possible to
The Area of Power Loop
FB Pin and the node must keep away from dynamic node of
The area of main current loop should be as small as
transformer.
possible to reduce EMI radiation, such as the primary
current loop, the snubber circuit and the secondary
rectifying loop.
WINSEMI
MICROELECTRONICS
WINSEMI
MICROELECTRONICS
www.winsemi.com Tel : +86-755-8250 6288
WINSEMI
MICROELECTRONICS
Fax : +86-755-8250 6299
WINSEMI
MICROELECTRONICS
WINSEMI
MICROELECTRONICS
6/8
WS9256ProductDescription
Package Information
DIP7 Package Outline Dimensions
Winsemi
Dimensions in Millimeters
Symbol
Min
Max
Min
Max
A
9.00
9.50
0.354
0.374
B
6.10
6.60
0.240
0.260
C
3.0
3.4
0.118
0.134
A1
1.474
1.574
0.058
0.062
A2
0.41
0.53
0.016
0.021
A3
2.44
2.64
0.096
0.104
A4
0.51TYP
0.02TYP
A5
0.99TYP
0.04TYP
C1
6.6
C2
7.30
0.260
0.50TYP
0.287
0.02TYP
C3
3.00
3.40
0.118
0.134
C4
1.47
1.65
0.058
0.065
D
7.62
9.3
0.300
0.366
D1
0.24
0.32
0.009
0.013
D2
WINSEMI
Dimensions in Inches
MICROELECTRONICS
7.62TYP
WINSEMI
MICROELECTRONICS
www.winsemi.com Tel : +86-755-8250 6288
WINSEMI
0.3TYP
MICROELECTRONICS
Fax : +86-755-8250 6299
WINSEMI
MICROELECTRONICS
WINSEMI
MICROELECTRONICS
7/8
WS9256ProductDescription
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:Futian District, ShenZhen Tian An Cyber Tech Plaza two East Wing 1002
Post Code : 518040
Tel : +86-755-8250 6288
FAX : +86-755-8250 6299
Web Site : www.winsemi.com
WINSEMI
MICROELECTRONICS
WINSEMI
MICROELECTRONICS
www.winsemi.com Tel : +86-755-8250 6288
WINSEMI
MICROELECTRONICS
Fax : +86-755-8250 6299
WINSEMI
MICROELECTRONICS
WINSEMI
MICROELECTRONICS
8/8