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WS2285 Product Description
Current Mode PWM Controller
Features
that is, at the condition of no load or light load, WS2285 can
�
Burst Mode Control
reduce the switch frequency linearly which minimize the
�
5uA ultra-low startup current
switching power loss; the ultra-low startup current and
�
1.8mA Low operating current
operating current make a reliable power for startup design,
�
Built-in Leading-edge blanking
and also large resistor can be used in the startup circuit to
�
Built-in synchronous slope compensation circuit
improve switching efficiency. The internal synchronous slope
�
Built-in Soft-Start
compensation circuit reduces the possible sub harmonic
�
65kHz fixed switch frequency
oscillation at high PWM duty cycle output.
�
Cycle by cycle over current protection (OCP)
Leading-edge blanking on current sense(CS) input removes
�
VDD over voltage clamp & under voltage
the signal glitch due to snubber diode circuit reverse
lockout( UVLO)
recovery and thus greatly reduces the external component
�
Over load protection (OLP)
count and system cost in the design.
�
OVP shut down latch
WS2285 offers comprehensive protection coverage with
�
Maximum Gate output voltage clamped at 12V
automatic self-recovery feature, including cycle by cycle over
�
Frequency jittering
current protection (OCP), over load protection (OLP), VCC
�
Ultra low standby power (<100mW)
Clamp, under voltage lockout (UVLO), OTP and OVP shut
down latch. The gate-driven output is clamped to maximum
12V to protect the internal MOSFET.
Applications
Excellent EMI performance is achieved by using the
Universal switch power supply equipment and offline
soft-switching
AC/DC flyback power converter
totem-pole-gate-drive output. The tone energy at below
�
Power Adapter
20KHZ is minimized in the design and audio noise is
�
Set-Top Box Power Supplies
eliminated during operation. The WS2285 is the ideal
�
Open-frame SMPS
substitute of the linear power supply or the RCC-mod e
�
Battery Charger
power, for a better performance of the whole switch power
and
frequency
jittering
at
the
system and a lower cost.
General Description
WS2285 is available in DIP8 package.
WS2285 is a high performance current mode PWM
controller, optimized for low power switch equipment.
For lower the standby power and higher RoHS
compliant, the IC offers a Burst Mode control feature
and ultra-low start-up current and operating current,
W/T-D017-Rev.A/2 May.2014
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WS2285 Product Description
Typical Application Circuit
V+
L
EM I
Filter
N
V-
1
2
3
4
N C
GND
VDD
GND
FB
D R A IN
CS
D R A IN
8
7
6
5
Output Power Table
230VAC±15%
85-265VAC
Adapter1
Adapter1
12W
8W
Product
WS2285
Note
Note: Maximum practical continuous power in an Adapter design with sufficient drain pattern as a heat sink, at 50℃ ambient.
Pin Definition and Device Marking
WS2285 is available in DIP8 package:
NC
VDD
1
8
2
7
3
FB
CS
D IP 8
4
6
GND
D: DIP8
GND
A:wafer information;
WS2285D8P
A1a
2C
D ra in
5
P: no Pb
1:Ver.; a: Package Code
2C:Y+M(2=2012 C=12 Month
D ra in
(1,2…A=10,B=11,C=12)
Pin Function Description
Pin
Pin
Name
Number
NC
1
NC
VDD
2
Power
3
Feedback
Input
FB
CS
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4
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Function Description
Floating pin
Power supply
Feedback input pin. The PWM duty cycle is determined by voltage level
into this pin and the current-sense signal at Pin 4. The internal protection
circuit will automatically shutdown when the FB voltage level exceeds a
preset threshold voltage.
Current sense input.
Current
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WS2285 Product Description
DRIAN
Monitoring
Power
transistor
drain
5/6
GND
7/8
This pin connects directly to the primary lead of the transformer and is
capable of switching a maximum of 600V
Ground
GND
Block Diagram
GND
OSC
VDD
Clamper
Driver
Output
Soft switch
Control
Trigger
and
L o g ic
Soft start
OCP
Comp
VDD
D R A IN
PWM Comparator
CS
LEB
Slope
Comp
UVLO
Vo lta g e
Divider
OLP
Internal
su p p ly
FB
Burst
Mode
Ordering Information
Package
IC Marking Information
8-DIP8, Pb-free
Purchasing Device Name
WS2285D8P
WS2285D8P
Recommended Operating Condition
Symbol
Parameter
Value
Unit
VCC
VCC supply voltage
10~30
V
TA
Operating temperature
-20~85
℃
Absolute Maximum Ratings
Symbol
Parameter
Value
Unit
Drain voltage(off-state)
Drain Input Voltage
-0.3~600
V
VDD
DC supply voltage
30
V
VFB
FB input voltage
-0.3~7
V
VCS
CS input voltage
-0.3~7
V
TJ
Operating junction temperature
-20~150
℃
TSTG
Storage temperature
-40~150
℃
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WS2285 Product Description
VCV
VDD clamp voltage
32
V
ICC
VDD DC clamp current
10
mA
Note
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
Value
Unit
VESD_HBM
Human model
3000
V
VESD_MM
Machine model
300
V
Electrical Characteristics
(VDD=16V，TA=25℃if not otherwise noted)
Supply Voltage (VCC)
symbol
parameter
Test condition
Min
VCC_OP
Operation voltage
UVLO_ON
Turn on threshold Voltage
6.5
UVLO_OFF
Turn-off threshold Voltage
12.5
I_VCC_ST
Start up current
VCC=13V
I_VCC_OP
Operation Current
VFB=3V
Vpull_up
Pull-up PMOS active
VDD_Clamp
VDD Zener Clamp Voltage
IVDD=10mA
30
OVP(ON)
Over
voltage
voltage
CS=0.3V,FB=3V,
Ramp up VCC until
gate clock is off
26
Vlatch_release
Latch release voltage
Typ
Max
Unit
30
V
7.5
8.5
V
13.5
14.5
V
5
20
uA
3.0
mA
32
34
V
28
30
V
0
13
protection
5
V
Feedback Input Section
VFB_Open
VFB Open Loop Voltage
Avcs
PWM input gain ΔVfb/ΔVcs
Vref_green
Vref_burst_H
Vref_burst_L
3.9
The threshold enter green
mode
The threshold exit burst
mode
The threshold enter burst
mode
IFB_Short
FB Pin Short Current
FB Shorted to GND
VTH_PL
Power limiting FB Threshold
TD_PL
Power limiting Debounce
ZFB_IN
Input Impedance
Max_Duty
Maximum duty cycle
5.0
V
2
V/V
2.1
V
1.3
V
1.2
V
0.32
0.48
mA
3.7
80
88
V
96
16
75
80
ms
KΩ
85
%
Current CS Section
SST
Soft Start time
4
ms
TLEB
Leading edge Blanking Time
220
ns
ZCS
Input impedance
40
KΩ
TD_OC
OCP control delay
120
ns
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WS2285 Product Description
VTH_OC
OCP threshold
FB＝3V
Vocp_clamping
0.75
V
0.9
V
Oscillator Section
Fosc
Fosc_BM
Normal Oscillation
VCC=14V,FB=3V,
Frequency
CS=0.3V
57
Burst mode frequency
Frequency variation versus
∆f_temp
temp. Deviation
Frequency variation
∆f_VDD
versus VDD
65
71
khz
22
khz
TEMP = -20 to 85℃
1
%
VDD = 12 to 25V
1
%
F_shuffling
Shuffling Frequency
32
Hz
∆f_OSC
Frequency Jittering
±4
%
MOSFET Section
MOSFET Drain-Source
BVdss
600
breakdown voltage
V
Static Drain to Source on
Ron
8.5
resistance
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WS2285 Product Description
Typical Operating Characteristics
。
Vth_otp(V)vs Temperatur( C)
5 .0
1.02
4 .5
1.01
V t h_ ot p(V )
Istartup(uA)
Istartup(uA) vs Temperature ( 。
C )
4 .0
3 .5
1.00
0.99
3 .0
0.98
-4 0
0
40
80
120
-40
。
Temperature ( C )
120
1 3 .8 0
UVLO(OFF)(V)
UVLO(ON)(V)
80
UVLO(OFF)(V) vs Temperature( 。
C )
8 .5 0
8 .3 0
8 .1 0
7 .9 0
1 3 .6 0
1 3 .4 0
1 3 .2 0
1 3 .0 0
7 .7 0
-4 0
0
40
80
120
-4 0
0
40
80
120
。
Temperature( C )
。
Temperature( C )
。
Fose(KHz)vs Temperature( C )
V th _ O C ( V ) v s d u ty ( % )
0 .9 5
6 4 .0
0 .9 0
6 3 .8
Fo s e(K H z )
Vth_OC(V)
40
。
Temperatur( C)
UVLO(ON)(V)vs Temperature(。C )
0 .8 5
0 .8 0
6 3 .5
6 3 .3
6 3 .0
0 .7 5
0
14
28
42
56
70
-4 0
D u ty ( % )
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40
80
120
。
Temperature( C )
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WS2285 Product Description
Function Description
For the burst mode control circuit, WS2285 self adjusts the
WS2285 is a high performance current mode PWM
switching mode according to the loading condition. At the
controller, optimized for low power AC/DC application. Ultra
condition of no load or light/medium load, the FB input
low startup current and operating current together with burst
voltage drops below burst mode threshold level. Device
mode feature minimize the standby power consumption and
enters Burst Mode control on the basis of the judgment. The
improve the switching efficiency. In addition to reduce the
gate drive output switches only when VCC voltage drops
external component count, the internal synchronous slope
below a preset level and FB input is active. Otherwise the
compensation combines with the leading-edge blanking
gate drive remains at off to minimize the switching loss and
improves system large stability and reduces the possible
power consumption to the greatest extend. The frequency
sub harmonic oscillation. WS2285 also have multiform
control also eliminates the audio noise at any loading
general recovery protection mode. The main function is
conditions.
described as below:
Oscillator Operation
Startup Current and Startup Control
The switching frequency is internally fixed at 65 kHz. No
Startup current of WS2285 is designed to be extremely low
external frequency setting components are required for PCB
at 5uA, so that VCC could be charged up above UVLO
design simplification.
threshold level and device starts up quickly. A large value
startup resistor can therefore be used to minimize the power
Current Sensing and Leading Edge Blanking
loss, predigest the design of startup circuit and provides
Cycle-by-Cycle current limiting is offered in WS2285. The
reliable startup in application. For the design of AC/DC
switch current is detected by a sense resistor into the sense
adaptor with universal input range, a startup resistor of 2 MΩ,
pin. An internal leading edge blanking circuit chops off the
1/8 W could be used together with a VCC capacitor to
sense voltage spike at initial MOSFET on state due to
provide a fast startup and low power dissipation solution.
snubber diode reverse recovery so that the external RC
filtering on sense input is no longer required. The current
Operating Current
limit comparator is disabled and thus cannot turn off the
The operating current of WS2285 is low at 1.8mA. Excellent
internal MOSFET during the blanking period. PWM duty
efficiency is achieved with low operating current together
cycle is determined by the current sense input voltage and
and extended burst mode control circuit.
the FB input voltage.
Soft Start
Internal Synchronized Slope Compensation
WS2285 features an internal 4ms soft start to soften the
Built-in slope compensation circuit adds slope voltage onto
electrical stress occurring in the power supply during startup.
the current sense input voltage for PWM generation. This
It is activated during the power on sequence. As soon as
greatly enhances the close loop stability at CCM and
VCC reaches UVLO （ OFF ）， the CS peak voltage is
prevents possible sub harmonic oscillation and thus reduces
gradually increased from 0.15V to the maximum level. Every
the output ripple voltage.
restart up is followed by a soft start.
Gate Drive
Extended Burst Mode Operation
The gate drive strength which is too weak leads to over
At zero load or light load, most of the power dissipation of
switch loss of MOSFET while too strong gate drive output
the switching power supply comes from the MOSFET
compromises in the over EMI. A good tradeoff between
switching loss, the core loss of the transformer and the loss
output strength and dead time control is achieved through
on the snubber circuit. The magnitude of power loss is in
the design of the built-in totem pole gate. The low standby
proportion to the number of switching events within a period
dissipation and good EMI system design is easier to achieve
of time. Therefore reducing the switch event leads to
through this dedicated devise. For MOSFET gate protection,
reduction on the power loss and thus saving the energy.
an internal 12V clamp is added at higher than expected VCC
W/T-D017-Rev.A/2 May.2014
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WS2285 Product Description
input.
condition when FB input voltage exceeds power limit
threshold value for more than TD_PL, control circuit reacts
Protection Controls
to shut down the output power MOSFET. Device restarts
Excellent system stability is achieved by the comprehensive
when VCC voltage drops below UVLO limit. It is clamped
protection of WS2285. Including Cycle-by-Cycle current
when VCC is higher than threshold value. The power
limiting (OCP), Over Load Protection (OLP) and over
MOSFET is shut down when VCC drops below UVLO limit
voltage clamp, VCC Clamp, Under Voltage Lockout on VCC
and device enters power on start-up sequence thereafter.
(UVLO), OTP and OVP shut down latch. At overload
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WS2285 Product Description
Package Information
DIP8 Package Outline Dimensions
D2
θ1
C1
C
C4
θ2
C2
C3
θ3
D1
A2
A5
A3
A1
D
A4
B
A
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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7.62TYP
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WS2285 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:Futian District, ShenZhen Tian An Cyber Tech Plaza two East Wing 1002
Post Code : 518040
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