WINSEMI WS2259DP

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 voltage lockout with hysteresis(UVLO)
■ Driver Output clamped(13V)
■ Soft-driver function for lower EMI
■ Frequency jitter
■ Constant output power limited
■ Over load protection(OLP)
■ Free audio noise operation
WS2259 which is optimized for high performance is a
highly integrated current mode PWM control IC. It is applied
for switch power of the small-sized and medium-sized for
example the power adaptor. For lower the standby power and
higher RoHS compliant, the IC has the Burst Mode function
and very low startup current and working 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 low startup current and low operating current
contribute to a reliable power on startup design with WS2259.
A large value resistor could thus be used in the startup circuit
to minimize the power consumption and improve the efficiency
of the power convert.
The internal synchronous slope compensation circuit
improves system large signal stability and reduces the
possible subharmonic oscillation at high PWM duty cycle
output. Leading-edge blanking on current sense(SENSE)
input removes the signal glitch due to snubber circuit diode
reverse recovery and thus greatly reduces the external
component count and system cost in the design.
WS2259 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,
under voltage lockout (UVLO). The gate-driven output is
clamped to maximum 13V to protect the external MOSFET.
Excellent EMI performance is achieved by using the frequency
jitter and the soft-switching at the totem pole gate drive output.
The tone energy at below 20KHZ is minimized in the design
and audio noise is eliminated during operation. The IC can be
used as the best alternative products of the linear power
supply or the RCC-mode power to improve the whole
performance of the switch power system and lower the cost.
WS2259 is offered in SOT23-6, SOP-8 and DIP-8 packages.
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
Rev.A Apr.2011
[email protected] Microelectronics Co., Ltd., All right reserved.
WS2259
Pin Definition and Device Marking
WS2259 is offered in SOT23-6, SOP-8 and DIP-8 packages,as shown below:
1
6
GND
GATE
2
S O T 2 3 -6
FB
3
VDD
4
RI
GATE
59: WS2259
Y: Year Code (1:2011; 2:2012……)
WW: Week Code (1-52)
5
SENSE
1
8
2
7
VDD
3
GND
D IP 8
SOP8
FB
WS2259XP
6
NC
NC
4
Dvf
5
SENSE
YWW
RI
X: D = DIP8 , S = SOP8
P: P = Pb-free package
D: 芯片代码
V: 内部版本号 (可选 1-9)
f: 工厂代码
Y: Year Code (1:2011; 2:2012……)
WW: Week Code (1-52)
Ordering Information
Package
8-Pin DIP8,
8-Pin SOP8,
Pb-free
Pb-free
6-Pin SOT23-6, Pb-free
IC Marking Information
Purchasing Device Name
WS2259DP
WS2259DP
WS2259SP
WS2259SP
59XXX
WS2259YP(SOT23-6)
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WS2259
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
Floating
Floating
Current
Current sense input.
NC
3
SENSE
4/4
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
Feedback input pin. The PWM duty cycle is determined by voltage into
Input
this pin and the current-sense signal at Pin 4
Ground
Ground
Block Diagram
OSC
VDD
clamp
Soft
driver
Logic
OCP
Slope
UVLO
Internal
Supply
PWM
OLP
Soft
Start
LEB
compensation
Voltage
Divider
Burst
Mode
3/11
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WS2259
Recommended Operating Condition
Symbol
Parameter
Value
Unit
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
VFB
FB input voltage
-0.3~7
V
VSENSE
SENSE input voltage
-0.3~7
V
VRI
RI input voltage
-0.3~7
V
TJ
Operation Junction Temperature
-20~150
℃
TSTG
Storage Temperature
-40~150
℃
VCV
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
Value
Unit
VESD-HBM
Human body model on all pins
3
KV
VESD-MM
Machine model on all pins
300
V
4/11
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WS2259
Electrical Characteristics (TA=25℃,VCC=16V, if not otherwise noted)
Supply Voltage (VDD)
Parameter
Symbol
Test condition
Min
Operation voltage
VDD_OP
Turn on threshold Voltage
UVLO_ON
6.8
Turn-off threshold Voltage
UVLO_OFF
13.5
Start up current
I_VDD_ST
Operation Current
I_VDD_OP
VDD=13V,RI=100K
Typ
Max
Unit
30
V
7.5
8
V
14.5
15.5
V
4
10
uA
1.7
2.3
mA
VDD=16V,RI=100K,VFB=3V
GATE with 1nF to GND
VDD_OVP
VDD Zener Clamp Voltage
29
V
31
V
VDD_Clamp
IVDD=10mA
VFB Open Loop Voltage
VFB_Open
VDD=16V,FB open,
5.4
5.9
6.4
V
FB Pin Short Current
IFB_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
72
77
82
%
Feedback Input Section
VDD=16V,FB open,
CS=0,RI=100KΩ
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
330
ns
70
ns
0.68
0.78
0.78
60
65
70
V
Oscillator Section
Frequency
Fosc
VDD=16V,RI=100K,,FB=3.2V
Jitter period
For 65K
Jitter range
khz
4
ms
±5
%
Burst mode frequency
Fosc_BM
VDD=9.5V,RI=100K, FB=1V
22
khz
Frequency variation versus temp. Deviation
∆f_temp
TEMP = -20 to 85℃
5
%
Frequency variation versus VDD
∆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
5/11
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WS2259
Typical Operating Characteristics
6/11
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WS2259
Function Description
WS2259 is a highly integrated current mode PWM control
At very light load or no load condition, the IC operates in
IC which is optimized for high performance. It is applied
Burst Mode. In this condition, the voltage at FB is below
for switch power of the small-sized and medium-sized for
burst mode threshold level, thus system goes into burst
example the power adaptor. The low startup current,
mode. The gate dive output switches only when VCC
operation current and burst mode function at the condition
voltage drops below a preset level or FB input is active to
of no load and low load can decrease the standby power
output an on state. Otherwise the gate drive remains at off
of the system, and improve the power convert efficiency.
state to minimize the switching loss thus reduce the
The internal synchronous slope compensation, the
standby power consumption. The standby current of
leading edge blanking function of the Sense pin not only
WS2259 is low as 800uA, Thus the standby of WS2259
decrease the component number, but also improve the
can be low than 100mW. The frequency control also
stability of the system and avoid the harmonics generation.
eliminates the audio noise at any loading conditions.
WS2259 also have multiform general recovery protection
mode. The main function is described as below.
Oscillator Operation
A resistor connected between RI and GND sets the
Startup Current and Startup Control
charge/discharge time of the constant current source to
Startup current of WS2259 is designed to be very low
the internal cap and thus the PWM oscillator frequency is
(4uA) so that VDD could be charged up above UVLO
determined. The relationship between RI and switching
threshold level and starts up quickly. A large value startup
frequency follows the below equation:
resistor can therefore be used to minimize the power loss,
predigest the design of startup circuit and provides
FOSC =
reliable startup in application. For the design of AC/DC
adaptor with universal input range, a startup resistor of 2
MΩ, 1/8 W could be used together with a VDD capacitor
6500
(Khz )
RI(Kohm )
If RI floating, the frequency will be internal set at 50 KHz
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
Operating Current
switch current is detected by a sense resistor into the
The operating current of WS2259 is very low .Good
SENSE pin. The internal Leading-edge blanking chops off
efficiency is achieved with low operating current together
the sense voltage spike at initial MOSFET on state due to
with extended burst mode control circuit which can easy
snubber diode circuit reverse recovery and thus reduce
the design of VDD capacitor.
the external RC filter circuit. The current limit comparator
is disabled and cannot turn off the external MOSFET
during the blanking period. PWM duty cycle is determined
by voltage level into SENSE pin and FB pin.
Soft-start
As soon as VDD reaches UVLO(on), the soft-start
function operates, the peak current is then gradually
increased from zero. Every restart attempt is followed by
Internal Synchronized Slope Compensation
4ms soft-start.
Built-in slope compensation circuit adds slope voltage
onto the current sense input voltage for PWM generation.
This greatly improves the close loop stability at CCM and
prevents the sub-harmonic oscillation and thus reduces
Burst Mode
the output ripple voltage.
Rev.A Apr.2011
7/11
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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 help to achieve
good EMI system design is easier to achieve through this
constant output power limit over the universal input
dedicated devise. For MOSFET gate protection, an
voltage range.
protection
current
limiting
features
(OCP),
including
Over
Load
internal 13V clamp is added at higher than expected VCC
input.
8/11
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WS2259
ge Dimension
SOT23-6 Packa
Package
9/11
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WS2259
ckage Dimension
DIP-8 Pa
Package
10/11
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WS2259
SOP-8 Package Dimension
Unit: mm
11/11
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