20160401090711 2258

WS2297B Product Description
WS2297B Switch Power Supply PWM Controller
Features
Description

Low startup current (4uA)

Low operation current (1.7mA,0.9mA
which is optimized for high performance. It is applied for small and
operation current at no-load)
medium-sized power supply devices, for example, the power adapter.
The WS2297B is a highly integrated current mode PWM switch IC
For lower standby power consumption and higher energy saving

Low Standby power

Current mode operation

Advanced frequency jittering control

Secondary Rectifier Short Protection

Cycle by cycle Over Current Protection
energy-saving at no-load contribute to minimize the power consumption
(OCP)
(<75mw) and meet the efficiency standard of DoE or ErP VI.
requirement, the IC has the Burst Mode function and very low startup
current and operating current. At the condition of no load or light load,
the IC operates in extended ‘burst mode’ to minimize switching loss by
lower
the
switching
frequency. The
patented
technologies
of
The WS2297B applies advanced frequency jittering control to

CS open protection

Over temperature protection(OTP)

Soft-start function

VDD over voltage protection and clamp

Under voltage lockout with hysteresis
system large signal stability and reduces the possibility of the
(UVLO)
sub-harmonic oscillation at high PWM duty cycle output. Leading-edge

Wide operation voltage (7.5-34V)
blanking on current sense input avoids the signal glitch due to snubber

Driver Output clamped(13V)
circuit diode reverse recovery and thus greatly reduces the external

Soft-driver function for lower EMI

Frequency jittering

Constant output power limited

Over load protection(OLP)
improve EMI performance at half load and light-load. Besides, it covers
wide supply voltage(7.5-34V), which greatly facilitate the transformer
design and the compatibility of the system.
The internal synchronous slope compensation circuit improves
component count and system cost in the design.
The WS2297B offers complete protection coverage with automatic
self-recovery feature including cycle by cycle over current protection
(OCP), over load protection (OLP), over temperature protection (OTP),
VDD over Voltage Protection (OVP), under voltage lockout (UVLO),
Secondary rectifier short protection. The gate-driven output is clamped
to maximum 13V to protect the external MOSFET.
Applications
Excellent EMI performance is achieved by using the frequency jitter
Universal switch power supply and offline
energy at below 20KHz is minimized in the design and audio noise is
AC/DC flyback converter:




and the soft-switching at the totem pole gate drive output. The audio
eliminated during operation.
Battery Charger
The WS2297B can be used as the best alternative products of the
Power Adaptor
linear power supply or the RCC-mode power to improve the whole
Set-Top Box Power Supplies
performance of the switching power system and lower the cost.
Open-frame SMPS
The WS2297B is available in DIP7 package.
WINSEMI
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WINSEMI
MICROELECTRONICS
[email protected] Microelectronics Co., Ltd., All right reserved.
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0322
WS2297B Product Description
Typical Application Circuit
Pin Configuration and Marking Information
The WS2297B is available in DIP7 Package. The top marking is shown as below:
WS2297BD7P:Product Code
A:Product Code
X:Internal Code
BCY:Internal Code For QC
YMX:D/C
Pin Definition
Pin Name
Pin No.
Pin Type
NC
1
NC
VDD
2
Power
FB
3
CS
4
DRIAN
5/6
Drain
GND
7
Ground
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Function Description
Hanged out
Power Supply
Feedback
Feedback input pin. The PWM duty cycle is determined by voltage into this
Input
pin and the current-sense signal at Pin 4
Current
Current monitoring feed-back input pin.To determine whether to reach the
monitoring
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limit value.
The drain terminal of Power MOSFET,connected with the transformer
primary side.
Ground
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WS2297B Product Description
Internal Block Diagram
GND
VD D
5 .5 V
In te rn a l
su p p l y
U VL O
VDD_OVP
VD D _ l o w
O SC
VD D _ l o w
DRAIN
OLP
Bu rst
mo d e
FB
So ft
d ri ve r
Logic
VD D _ l o w
OTP
OVP
1V I_ sa ve
Sl o p e
co mp
CS
CS
100u
PW M
L EB
2.5V
OCP
OTP
clamp
SBD sh o rt
Ordering Information
Package
Marking
Part Number
7-Pin DIP-7, Pb-free
WS2297BD7P
WS2297BD7P(DIP-7)
Output Power
230VAC±15%
85-265VAC
Adapter1
Adapter1
24W
18W
Product
WS2297B
NOTE:The above data was tested in the adapter which in ambient temperature of 50 degrees Celsius and enough heat radiation
Recommended Operation Conditions
Symbol
Parameter
Value
Unit
VDD
VDD Supply Voltage
10~30
V
TA
Operating temperature
-20~85
℃
Symbol
Parameter
Value
Unit
VDD
DC Power Supply
34.5
V
VFB
FB input voltage
-0.3~7
V
Absolute Maximum Ratings
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WS2297B Product Description
VSENSE
SENSE input voltage
-0.3~7
V
VDRAIN
DRAIN pin voltage
-0.3~650
V
TJ
Operation Junction Temperature
-20~150
℃
TSTG
Storage Temperature
-40~150
℃
VCV
Vcc Clamp Voltage
35.5
V
ICC
Vcc Clamp Continuous Current
10
mA
Note: Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are
stress ratings only, functional operation of the device at these or any other conditions beyond those indicated in the
Recommended Operating Conditions section are not implied. Exposure to absolute maximum-rated conditions for extended
periods may affect device reliability.
ESD Information
Symbol
Parameter
VESD-HBM
Human body model on all pins
VESD-MM
Machine model on all pins
Value
Unit
3
KV
300
V
Electrical Characteristics
Supply Voltage (VDD)
symbol
parameter
Test condition
Min
Typ
Max
Unit
34
V
VDD_OP
Operation voltage
UVLO_ON
Turn on threshold Voltage
7.2
8.1
9.0
V
UVLO_OFF
Turn-off threshold Voltage
14.0
15.0
16.0
V
I_VDD_ST
Start up current
4
10
uA
I_VDD_OP
Operation Current
1.7
2.5
mA
VDD=13V
VDD=16V, VFB=3V
GATE with 1nF to GND
VDD_OVP
VDD_Clamp
VDD Zener Clamp Voltage
IVDD=10mA
34.5
V
35.5
V
Feedback Input Section
VFB_Open
VFB Open Loop Voltage
VDD=16V,FB open,
4.3
5.0
5.6
V
IFB_Short
FB Pin Short Current
FB Shorted to GND
0.22
0.315
0.41
mA
VTH_PL
Power limiting FB Threshold
VDD=16V
3.2
3.65
4.0
V
TD_PL
Power limiting Debounce
VDD=16V,FB open
48
60
72
ms
ZFB_IN
Input Impedance
VDD=16V,FB=2V/3V,CS open
13
16.5
20
kΩ
Current Sense Section
TLEB
Leading edge Blanking Time
330
ns
TD_OC
OCP control delay
GATE with 1nF to GND
70
ns
VTH_OC
OCP threshold
FB=3.4V
0.690
0.740
0.790
V
Max_OC
Max_OCP for line comp
FB=3.4V
0.9
0.95
1
V
Vth_SBD
CS threshold for SBD short
VDD=16V
Td_SBD
Delay of SBD short protect
8 PWM cycle
2.0
V
8
CLK
Oscillator Section
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WS2297B Product Description
Fosc
Frequency
VDD=16V,FB=3.2V
60
65
70
khz
D_max
Max duty
VDD=16V,FB=3.2V
68
75
82
%
Jitter period
For 65K
4
ms
Jitter range
For 65K
±5
%
VDD=16V, Fb fall from 2V to burst
22
khz
TEMP = -20 to 85℃
5
%
VDD = 12 to 25V
5
%
150
℃
Fosc_BM
Burst mode frequency
Frequency
∆f_temp
variation
versus
temp. Deviation
∆f_VDD
Frequency variation versus VDD
Thermal protection
T_shutdown
Thermal shutdown temperature
Power MOSFET Section
MOSFET Drain-Source
BVdss
650
breakdown voltage
Static Drain to Source on
Ron
WS2297B
resistance
IDSS
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V
1.95
Output clamp voltage
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2.3
ohm
10
uA
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WS2297B Product Description
Application Information
Soft-start
As soon as VDD reaches UVLO (on), the soft-start
The WS2297B is a highly integrated and high
performance current mode PWM switch IC. It is applied for
small and medium-sized power (<18W)supply devices, for
function operates; the peak current is then gradually
increased from zero. Every restart attempt is followed by
4ms soft-start
example, the power adapter and chargers. The low startup
current, operation current and burst mode function at the
Burst Mode
condition of no load and light load can decrease the standby
At very light load or no load condition, the IC operates in
power of the system, and improve the power conversion
Burst Mode. In this condition, the voltage at FB is below
efficiency. The patented technologies of energy-saving at
burst mode threshold level, thus system goes into burst
no-load and RT pin energy-saving contribute to minimize the
power consumption (<75mw) and meet the efficiency
standard of DoE or ErP VI. The internal synchronous slope
mode. The gate dives output switching only when VDD
voltage drops below a preset level or FB input is active to
output an on state. Otherwise the gate drive remains at off
state to minimize the switching loss thus reduce the standby
compensation and the leading edge blanking function of the
power consumption. The frequency control also eliminates
Sense pin not only decrease the component number, but
the audio noise at any load conditions.
also improve the stability of the system and avoid the
harmonics generation. The WS2297B also has multiform
Advanced Frequency Jitter Control
The WS2297B integrates the maximum operating
auto-recovery protection. The main functions are described
frequency of 65 KHz. The frequency jittering range is in
as below.
proportion to the switching frequency in traditional PWM
controller, so that at half load or light load, the switching
Startup Current and Startup Control
Startup current of the WS2297B is designed to be very
low(4uA) so that VDD could be charged up above UVLO
threshold level and starts up quickly. A large value startup
resistor can therefore be used to minimize the power loss,
frequency is decreased, and the frequency jittering range is
also decreased, which deteriorates the EMI performance.
The WS2297B applies advanced frequency jittering control
to keep better EMI performance at all load condition.
predigest the design of startup circuit and provide reliable
startup in application. For the design of AC/DC adaptor with
universal input range, a 1206 resistor of 1.5 MΩ could be
used together with a VDD capacitor to provide a fast startup
and low power dissipation solution.
Operating Voltage
The WS2297B covers wide supply voltage from 7.7V to
34V, which helps easing the transform design, and a same
transform can be used to design different output voltage, so
that the compatibility is improved
Current Sensing and Leading Edge Blanking
Operating Current
Cycle-by-Cycle current limiting is offered in WS2297B.
The operating current of the WS2297B is very low.
The switching current is detected by a sense resistor at the
Good efficiency is achieved with low operating current
SENSE pin. The internal Leading-edge blanking chops off
together with extended burst mode control circuit which can
the sense voltage spike at initial MOSFET on state due to
decrease the value of VDD capacitor.
snubber diode circuit reverse recovery and thus reduce the
external RC filter circuit. The current limitation comparator is
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WS2297B Product Description
disabled and cannot turn off the external MOSFET during
the blanking period. PWM duty cycle is determined by
voltage level at SENSE pin and FB pin.
will cause higher switching loss of MOSFET, while too
strong gate drive output cause EMI problem. A good tradeoff
between output capacity and dead time control is achieved
through the design of the built-in totem pole driver in the
Internal Synchronized Slope Compensation
Built-in slope compensation circuit adds slope voltage
WS2297B. The low standby dissipation and good EMI
onto the current sense input voltage for PWM generation.
system design is easier to achieve through this dedicated
This greatly improves the close loop stability at CCM and
device. For MOSFET gate protection, an internal 13V clamp
prevents the sub-harmonic oscillation and thus reduces the
is added.
output ripple voltage.
Protection Controls
CS Open Protection & Secondary Rectifier Short
Good power supply system reliability is achieved with
Protection
auto-recovery protection features including Cycle-by-Cycle
When the CS pin is opened, the WS2297B will shut
down after a few cycles. When the secondary rectifier is
short, the WS2297B will be in protection state after 8 pulse
periods of VDD. The controller enters into UVLO auto
current limiting (OCP), Over Load Protection (OLP), Over
Temperature
Protection
(OTP),
CS
open
Secondary Rectifier Short Protection,
protection,
Under Voltage
Lockout on VDD (UVLO), , and VDD over Voltage Protection
& VDD clamp.
recovery until the fault is removed.
Internal line voltage compensation of OCP helps to
achieve constant output power limit over the universal input
voltage range.
Gate Driver
GATE pin of the WS2297B is connected to the gate of
an external MOSFET. If the gate drive capacity is too weak
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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
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Dimensions in Inches
7.62TYP
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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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