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WS2259
Features
General Description
■ Burst Mode function
■ Low startup current (4uA)
■ Low operation current (1.7mA)
■ Built in Leading edge blanking (LEB)
■ Built in Synchronous slope compensation
■ Current mode operates
■ External programmable switching frequency
■ Cycle by cycle Over Current Protection
■ over temperature protection(OTP)
■ Soft-start
■ VDD over voltage protection and clamp
■ under vo ltage lockout w ith h ysteresis(UVLO)
■ Driver Output clamped(1 3V)
■ Soft-driver function for lower EMI
■ Frequency jitter
■ Constant output power limited
■ Over load protection(OLP)
■ Ultra low standby power (<100mW)
■ Free audio noise operation
WS2259 w hich is o ptimize d fo r h igh pe rfo rmance is a
highly integ rate d current mode PWM control IC. It is a pplied
for switch power of the small-size d and med ium-size d fo r
example the power adaptor. For lower the stan dby power and
higher RoHS compliant, the IC has the Burst Mode fu nction
and ve ry low startup curre nt and w orking current. At the
cond ition of no load o r light load, the IC operates in e xten ded
‘b urst mode’ to minimize switching loss by lower the switchin g
freque ncy. The low startup current and low o perating curre nt
contribu te to a reliable power on startup d esign w ith WS2259.
A large value resistor could thus be used in the startup circuit
to minimize the power consumption and impro ve the e fficie ncy
of the power conve rt.
The internal synchronous slope compe nsation circuit
improves system large sig nal stability and reduces the
po ssible sub harmonic o scillatio n at high PWM du ty cycle
ou tput. Leading-edge b lan kin g on current sense(SEN SE)
in put removes the signa l glitch due to snubber circuit diode
reve rse recove ry and thus g re atly reduces the e xte rna l
component count and system cost in the d esign.
WS2259 o ffe rs complete p ro tection coverage w ith
automatic self-re co ve ry fe ature including cycle by cycle over
curren t p ro tection (OCP), over load p ro tection (OLP), over
temperatu re p ro tection (OTP), VDD Over Voltage Protection ,
under vo lta ge lockout (UVLO). The ga te-d riven ou tput is
clamped to maximum 1 3V to p ro tect the e xte rna l MOSFET.
ExcellentEMI p erforman ce is a ch ieve d by using the freq uency
jitter and the soft-switch ing at the totem po le gate d rive o utpu t.
The tone e nergy at below 20KHZ is minimized in the d esign
and audio noise is e limina ted d uring o peration . The IC can be
used as the b est a lternative products of the linea r power
supp ly o r the RCC-mode power to impro ve the whole
pe rformance of the switch power system and lower the cost.
WS2259 is o ffe re din SOT23-6, SOP-8 and D IP-8 p ackag es.
Applications
Universal switch power supply and offline AC/DC
flyback converter:
■ Battery Charger
■ Power Adaptor
■ Set-Top Box Power Supplies
■ Open-frame SMPS
Typical Application Circuit
W/T-D/S/Y005-Rev.A/1 Jul.2013
[email protected] Microelectronics Co., Ltd., All right r eserved.
WS2259
Pin Definition and Device Marking
WS2259 is offered in SOT23-6, SOP-8 and DIP-8 packages,as shown below:
1
GND
2
FB
6
5
S O T 2 3 -6
3
G A TE
VD D
59: WS2259
Y: Year Code (1:2011; 2:2012……)
M: month Code (1-12)
59 YMF
4
RI
SEN SE
GATE
1
8
2
7
VD D
3
D: DIP8 S: SOP P: no PbA:wafer
GND
D IP 8
S OP 8
information;
FB
NC
NC
4
1:Ver.; a: Package Code
WS2259D8/S8P
6
A1a
2C:Y+M(2=2012 C=12 Month
2C
(1,2…A=10,B=11,C=12)
5
SEN SE
RI
Ordering Information
Package
IC Marking Information
Purchasing Device Name
8-Pin DIP8,
Pb-free
WS2259DP
WS2259DP
8-Pin SOP8,
Pb-free
WS2259SP
WS2259SP
59XXX
WS2259YP(SOT23-6)
6-Pin SOT23-6, Pb-free
Pin Function Description
Pin Name
Pin No.
/SOT2
DIP8
DIP8/SOT2
/SOT233
Pin Type
Function Description
GATE
1/6
Output
Totem-pole gate drive output for the power MOSFET
VDD
2/5
Power
Power Supply
NC
3
Floating
Floating
SENSE
4/4
Current
Current sense input.
RI
5/3
NC
6
FB
7/2
GND
8/1
Monitoring
Frequency
Internal oscillator frequency setting pin. A resistor which is
Setting
connected between RI and GND sets the PWM frequency
Floating
Floating
Feedback
Input
Ground
Feedback input pin. The PWM duty cycle is determined by voltage into
This pin and the current-sense signal at Pin 4
Ground
2/10
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WS2259
Block Diagram
Recommended Operating Condition
Symbol
Parameter
Value
U nit
VDD
VDD Supply Voltage
10~30
V
RI
RI Resistor
100
Kohm
TA
Operating temperature
-20~85
℃
Absolute Maximum Ratings ( Note 1)
Symbol
Parameter
Value
Unit
VDD
DC Power Supply
30
V
V FB
FB input voltage
-0.3~7
V
V SENSE
SENSE input voltage
-0.3~7
V
V RI
RI input voltage
-0.3~7
V
TJ
Operation Junction Temperature
-20~150
℃
TSTG
Storage Temperature
-40~150
℃
V CV
Vcc Clamp Voltage
31
V
ICC
Vcc Clamp Continuous Current
10
mA
Note 1: 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
V ESD-HBM
Human body model on all pins
V ESD-MM
Machine model on all pins
Value
U nit
3
KV
300
V
3/10
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WS2259
Electrical Characteristics (TA=25℃,VCC=16V, if not otherwise noted)
Supply Voltage (VDD)
Parameter
Symbol
Operation voltage
VDD_OP
Turn on threshold Voltage
UVLO_ON
7
Turn-off threshold Voltage
UVLO_OFF
13.5
Start up current
I_VDD_ST
Operation Current
I_VDD_OP
VDD Zener Clamp Voltage
Test condition
Min
VDD=13V,RI=100K
VDD=16V,RI=100K,VFB=3V
GATE with 1nF to GND
Typ
Max
Unit
30
V
8
9
V
14.5
15.5
V
4
10
uA
3.0
mA
0.6
VDD_OVP
29
V
VDD_Clamp IVDD=10mA
31
V
Feedback Input Section
V FB Open Loop Voltage
VFB_Open
VDD=16V,FB open,
5.4
5.9
6.4
V
FB Pin Short Current
I FB_Short
FB Shorted to GND
0.3
0.45
0.6
mA
Power limiting FB Threshold
VTH_PL
VDD=16V, RI=100K
3.2
3.65
4.0
V
Power limiting Debounce
TD_PL
VDD=16V,FB open,RI=100KΩ
48
60
72
ms
Input Impedance
ZFB_IN
VDD=16V,FB=2V/3V,CS open
11.5
14.5
18
kΩ
Maximum duty cycle
Max_Duty
VDD=16V,FB open, CS=0,RI=100KΩ
72
77
82
%
Current Sense Section
Leading edge Blanking Time
TLEB
OCP control delay
TD_OC
GATE with 1nF to GND
OCP threshold
TTH_OC
FB=3.2V
Fosc
VDD=16V,RI=100K,,FB=3.2V
330
ns
70
ns
0.675 0.725 0.775
V
Oscillator Section
Frequency
60
Jitter period For 65K
Jitter range
Burst mode frequency
Frequency variation versus temp.
Deviation
Frequency variation versus VDD
65
70
khz
4
ms
±5
%
22
khz
Fosc_BM
VDD=9.5V,RI=100K, FB=1V
∆f_temp
TEMP = -20 to 85℃
5
%
∆f_VDD
VDD = 12 to 25V
5
%
VRI
VDD=16V,RI=100KΩ,CS=1V
RI Section
RI voltage
1.94
2
2.06
V
Thermal protection
Thermal shutdown temperature
T_shutdown
℃
150
GATE Output Section
Output voltage Low
VOL
VDD = 16V, Io = -20mA
0.8
V
Output voltage high
VOH
VDD = 16V, Io = 20mA
9
Output clamp voltage
VClamp
VDD = 20V
11
Rising time
Tr
VDD = 16V, GATE with 1nF to GND
250
ns
Falling time
Tf
VDD = 16V, GATE with 1nF to GND
75
ns
V
13
14.5
V
4/10
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WS2259
Typical Operating Characteristics
5/10
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WS2259
Function Description
WS2259 is a highly integrated current mode PWM control
IC which is optimized for high performance. It is applied
for switch power of the small-sized and medium-sized for
example the power adaptor. The low startup current,
operation current and burst mode function at the condition
of no load and low load can decrease the standby power
of the system, and improve the power convert efficiency.
The internal synchronous slope compensation, the
leading edge blanking function of the Sense pin not only
decrease the component number, but also improve the
stability of the system and avoid the harmonics generation.
WS2259 also have multiform general recovery protection
Burst Mode
At very light load or no load condition, the IC operates in
Burst Mode. In this condition, the voltage at FB is below
burst mode threshold level, thus system goes into burst
mode. The gate dive output switches only when VCC
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 power consumption. The standby current of
WS2259 is low as 800uA, Thus the standby of WS2259
can be low than 100mW. The frequency control also
eliminates the audio noise at any loading conditions.
mode. The main function is described as below.
Oscillator Operation
A resistor connected between RI and GND sets the
charge/discharge time of the constant current source to
Startup Current and Startup Control
Startup current of WS2259 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
the internal cap and thus the PWM oscillator frequency is
determined. The relationship between RI and switching
frequency follows the below equation:
resistor can therefore be used to minimize the power loss,
FOSC =
predigest the design of startup circuit and provides
reliable startup in application. For the design of AC/DC
adaptor with universal input range, a startup resistor of 2
6500
(Khz )
RI (Kohm )
If RI floating, the frequency will be internal set at 50 KHz
MΩ, 1/8 W could be used together with a VDD capacitor
to provide a fast startup and low power dissipation
solution.
Current Sensing and Leading Edge Blanking
Cycle-by-Cycle current limiting is offered in WS2259. The
switch current is detected by a sense resistor into the
SENSE pin. The internal Leading-edge blanking chops off
the sense voltage spike at initial MOSFET on state due to
Operating Current
The operating current of WS2259 is very low .Good
snubber diode circuit reverse recovery and thus reduce
efficiency is achieved with low operating current together
is disabled and cannot turn off the external MOSFET
with extended burst mode control circuit which can easy
during the blanking period. PWM duty cycle is determined
the design of VDD capacitor.
by voltage level into SENSE pin and FB pin.
the external RC filter circuit. The current limit comparator
Internal Synchronized Slope Compensation
Soft-start
Built-in slope compensation circuit adds slope voltage
As soon as VDD reaches UVLO(on), the soft-start
onto the current sense input voltage for PWM generation.
function operates, the peak current is then gradually
This greatly improves the close loop stability at CCM and
increased from zero. Every restart attempt is followed by
prevents the sub-harmonic oscillation and thus reduces
4ms soft-start.
the output ripple voltage.
6/11
W/T-D/S/Y005-Rev.A/1 Jul.2013
Steady, keep you advance
WS2259
Gate Driver
Protection Controls
GATE pin of WS2259 is connected to the gate of an
Good power supply system reliability is achieved with
external power switch. The gate drive strength which is
auto-recovery
too weak leads to over switch loss of MOSFET while too
Cycle-by-Cycle
strong gate drive output compromises in the over EMI. A
Protection (OLP), Under Voltage Lockout on VDD (UVLO),
good tradeoff between output strength and dead time
Over Temperature Protection (OTP), and VDD Over
control is achieved through the design of the built-in totem
Voltage Protection & VDD clamp.
pole gate in WS2259. The low standby dissipation and
Internal line voltage compensation of OCP helps to
good EMI system design is easier to achieve through this
achieve constant output power limit over the universal
dedicated devise. For MOSFET gate protection, an
input voltage range.
protection
current limiting
features
(OCP),
including
Over
Load
internal 1 3V clamp is added at higher than expected VCC
input.
7/10
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WS2259
SOT23-6 Packa
ge Dimension
Package
8/10
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WS2259
DIP-8 Pa
ckage Dimension
Package
9/10
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WS2259
SOP-8 Package Dimension
10/10
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