WS9442 [ETC]
Non-isolated Buck Offline LED Driver;型号: | WS9442 |
厂家: | ETC |
描述: | Non-isolated Buck Offline LED Driver |
文件: | 总9页 (文件大小:588K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
WS9442 Product Description
Non-isolated Buck Offline LED Driver
Features
Description
Critical Conduction Mode Operation
Internal 500V Power MOSFET
Gate Drive and No Auxiliary Winding
±3% LED Current Accuracy
Efficiency up to 93%
The WS9442 is a high precision buck constant current
LED driver and is applied to non-isolated buck LED power
system with AC input voltage of 85VAC-265VAC. The
WS9442 integrates a 500V power MOSFET, and can
achieve excellent constant current performance with very
few external components, so the system cost and size are
minimized. The driver operates in critical conduction mode,
and the output current does not change with the inductance
and LED output voltage. The operating current of the IC is
200uA, so it doesn’t need the auxiliary winding for supplying
the chip, thus simplifying design and reducing cost.
LED Short Circuit Protection
LED Open Circuit Protection
Current Sense Resistor Short Protection
Thermal Regulation Function
Applications
The WS9442 adopts intelligent temperature control and
thoroughly solves the problem of light flashing at high
temperatures. The WS9442P offers full protection functions
to improve the system reliability, including LED open circuit
protection, LED short circuit protection, CS resistor short
LED Bulb Lights
LED Panel Lights
LED Strings
circuit protection and thermal regulation function.
The WS9442 is available in DIP-7 Package.
Typical Application Circuit
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
Copyright@Winsemi Microelectronics Co., Ltd., All right reserved.
0318
WS9442 Product Description
Pin Configuration and Marking Information
The WS9442 is available in DIP-7 Package. The top marking is shown as below:
WS9442D7P:Product Code
A:Product Code
X:Internal Code
BCY:Internal Code For QC
YMX:D/C
Pin Definition
Pin No.
Description
Name
1
GND
Ground
2
3
ROVP
NC
Over Voltage Protection Setting Pin. Connect a resistor to GND
No Connection.Should be hanged out.
Power Supply Pin
4
VCC
5,6
DRAIN
Internal HV Power MOSFET Drain
Current Sense Pin. Connect a sense resistor between this pin and GND
pin.
7
CS
Block Diagram
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
www.winsemi.com
Tel : +86-755-8250 6288
Fax : +86-755-8250 6299
2/9
WS9442 Product Description
Ordering Information
Package
Marking
Part Number
7-Pin DIP-7, Pb-free
WS9442D7P
WS9442D7P
Recommended Operation Conditions
Part Number
Package
Input voltage
Maximum output power
120V/280mA
160V/220mA
175VAC-264VAC
90VAC-264VAC
WS9442D7P
DIP7
80V/300mA
Absolute Maximum Ratings
Symbol
VDS
Parameter
Range
-0.3~500
10
Unit
V
Internal HV MOSFET drain voltage
VCC pin maximum sink current
ICC_MAX
mA
V
VROVP
VCS
LED open circuit protection voltage regulation
Current sense pin input voltage
-0.3~7
-0.3~7
0.9
V
PDMAX
TJ
Power dissipation DIP7
W
Maximum operating junction temperature
Minimum/Maximum Storage temperature
150
℃
℃
TSTG
-55~150
Note:Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
www.winsemi.com
Tel : +86-755-8250 6288
Fax : +86-755-8250 6299
3/9
WS9442 Product Description
Electrical Characteristics (Unless otherwise specified, VCC=15V and TA =25 ℃)
Symbol
Parameter
Conditions
Min
Typ
Max
Units
Supply Voltage Section
VCC_CLAMP
UVLO_on
VCC Clamp Voltage
Chip Startup Voltage
VDD Under voltage
protection
10mA
17.8
14
18.8
15
19.8
16.2
V
V
UVLO_off
9
9.5
10
V
Ist
Startup Current
VCC= 13V
150
100
220
170
300
250
uA
uA
Iop
Operating Current
Fop=70KHz
Current Sense Section
Threshold Voltage for
Vcs_th
390
400
410
mV
Peak Current Limit
Leading Edge Blanking
Time for Current Sense
TLEB
350
200
ns
ns
TDELAY
Switch Off Delay Time
Internal Time Control Section
Toff_max
Minimum OFF Time
310
4.5
us
us
us
Toff_min
Maximum OFF Time
Maximum On Time
Rovp=70k
Ton_max
100
MOSFET Section
Static Drain-source
On-State Resistance
Drain-Source Breakdown
Voltage
Rds_on
BVdss
Idss
Vgs=15V,Ids=0.5A
Vgs=0V,Ids=250uA
Vgs=0V,Vds=500V
6.8
Ω
V
500
Drain-Source Leakage
Current
10
uA
Thermal Regulation Section
Thermal Regulation
TREG
150
℃
Temperature
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
www.winsemi.com
Tel : +86-755-8250 6288
Fax : +86-755-8250 6299
4/9
WS9442 Product Description
Function Description
The WS9442 is a high performance non-isolated buck
converter specially designed for LED lighting. The device
comparator, and the voltage on CS pin is compared with the
internal 400mV reference voltage. The MOSFET will be
switched off when the voltage on CS pin reaches the threshold.
The CS comparator includes a 350ns leading edge blanking
integrates
a 500V power MOSFET. With the help of
advanced constant current control and gate drive technology,
the converter achieves excellent constant current
performance with very few external components. It does not
need auxiliary winding for powering the IC or voltage sensing,
hence the system size and cost is greatly reduced.
time.
The peak inductor current is calculated by the equation:
400
IPK
(mA)
RCS
Start Up
Where, RCS is the current sense resistor value.
After system powered on, the VCC pin capacitor is
charged up by the start up resistor. When the VCC pin
voltage reaches the turn on threshold, the internal circuits
start operating. The WS9442 integrates a 17V ZENER diode
to clamp the VCC voltage. Due to the ultra-low operating
current, the auxiliary winding is not needed to supply the IC.
The typical value of the start-up current is 200uA (the
maximum value is 300uA). For the application of 176VAC—
264VAC, the start-up resistor can be calculated by the
equation:
The current in LED can be calculated by the equation:
IPK
ILED
(mA)
2
Where, IPK is the peak current of the inductor.
Freewheeling Diode
The diode will bear the reverse voltage equal to the input
voltage when the MOSFET is on. A 600V diode was
suggested to use. Besides, the operating frequency of
freewheeling diode is from 20K to 120 KHz, such ultra fast
recovery diodes as ES and ER whose Trr is less than 50ns are
good choice.
VIN _ MIN 1.414
1761.414
RST
820K
IST _ MAX
300
Two resistors in 1206 size SMD can be used in series.
VCC Capacitor Selection
Input Electrolytic Capacitor
The Vcc capacitor is used to bypass noise to IC, so that
to assure its stable operation, and should be as close as
possible to the chip.
Input voltage should be considered in to the capacitor
pressure, and the common value is 400V.
In general, the capacity design can be calculated by the
following empirical equations:
A 1uF capacitor can be used in Vcc. If selecting MLCC,
the material of X7R will be used to satisfy the stability of the
capacity under high temperatures. Due to external damage
resulted from small volume and brittle texture of MLCC, the
Vcc is easy to leakage currents, which will make the WS9442
unable to start. Strict control measures are taken in its layout
and productive process.
90Vac~264Vac: 1W output uses1uF
capacitor;
176Vac~264Vac: 1W output uses 0.5uF buck electrolytic
capacitor.
buck electrolytic
Output Capacitor
Electrolytic capacitor is recommended to be used. Its
stable capacitance can improve the efficiency of power supply,
the LED ripple current and luminous efficiency.
Vovp voltage should be considered in output capacitor
pressure.
Constant Current Control
The WS9442 utilizes proprietary current control method.
It can achieve precise LED output current with a few external
components. Cycle by Cycle current sense is adopted in
WS9442, the CS pin is connected to the current sense
Inductor Selection
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
www.winsemi.com Tel : +86-755-8250 6288
Fax : +86-755-8250 6299
5/9
WS9442 Product Description
The WS9442 works in
a
inductor critical current
dissipation are also reduced. The system temperature is
regulated and the system reliability is improved. The thermal
regulation temperature is set to 150℃ internally.
conduction mode. When the power MOFET is switched on,
the current in the inductor rises up from zero. The on time of
the MOSFET can be calculated by the equation:
Over Voltage Protection
L IPK
ton
The over voltage protection of the WS9442 can be
programmed by the ROVP pin resistor. The ROVP pin voltage
is 0.5V.
VIN VLED
Where,
L is the inductance value,
When the LED is open circuit, the period of the output
voltage increases gradually, the demagnetization time gets
shorter. The demagnetization time at OVP---- Tovp can be
calculated by the open circuit protection voltage by the
equation:
IPK is the peak current of the inductor,
VIN is the DC bus voltage after the rectifier bridge,
VLED is the voltage on the LED.
After the power MOSFET is also switched off and the
current in the inductor decreases. When the inductor current
reaches zero, the power MOSFET is turned on again by IC
internal logic. The off time of the MOSFET is given by the
equation:
L VCS
Tovp
RCS VOVP
Where,
L IPK
toff
Vcs is the CS pin turn off threshold (0.4V);
Vovp is the open circuit protection voltage.
And then the Rovp resistor value can be calculated by the
equation:
VLED
The inductance can be calculated by the equation:
VLED (VIN VLED
f IPK VIN
)
L
Rovp 120 7.67 * Tovp *10 6 (KΩ)
Where, f is the maximum system switching frequency,
which is proportional to the input voltage. So the minimum
switching frequency is set at lowest input voltage, and the
maximum switching frequency is set at highest input voltage.
The minimum and maximum off time of WS9442 is set at
4.5us and 310us, respectively. Referring to the equation of
Toff calculation, if the inductance is too small, the Toff may be
smaller than the minimum off time, the system will operate in
discontinuous conduction mode and the output current will
be smaller than the designed value. If the inductance is too
large, the Toff may be larger than the maximum off time, the
system will operate in continuous conduction mode and the
output current will be higher than the designed value. So it is
important to choose a proper inductance.
It is suggested that the open circuit protection voltage is
set at or above 1.5 times maximum load voltage.
Protection Function
The WS9442 offers rich protection functions to improve
the system reliability, including LED open/short protection, CS
resistor short protection, VCC under voltage protection,
thermal regulation. When the LED is open circuit, the system
will trigger the over voltage protection and stop switching.
When the LED short circuit is detected, the system works at
low frequency and the CS pin turnoff threshold is reduced. So
the system power consumption is very low. At some abnormal
fault condition, such as CS resistor shorted or inductor
saturation, the internal fast fault detection circuit will be
triggered, the system stops switching immediately.
Thermal Regulation
After the system enters into faulty condition, the VCC
voltage will decrease until it reaches the UVLO threshold, then
the system will restart again. If the fault condition is removed,
The WS9442 integrates thermal regulation function.
When the system is under higher temperature, the output
current is gradually reduced; the output power and thermal
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
www.winsemi.com
Tel : +86-755-8250 6288
Fax : +86-755-8250 6299
6/9
WS9442 Product Description
Ground Path: The power ground path for current sense
resistor should be short, and the power ground path should be
separated from small signal ground path before connecting to
the negative node of the bulk capacitor.
the system will recover to normal operation.
Line Voltage Compensation
The WS9442 integrates line voltage compensation
function, which makes LED current remain unchanged in the
range of full voltage with good line regulation and current
accuracy.
The Area of Power Loop: The area of main current loop
should be as small as possible to reduce EMI radiation. And it
should be away from diodes and other heating components.
ROVP PIN: The ROVP resistor should be as close as
possible to the ROVP Pin to increase its resistance to prevent
PCB Layout
from the interference.
The following rules should be followed in WS9442 PCB
layout:
DRAIN PIN: The copper area of DRAIN pin can be
increased for better thermal dissipation. And it should be away
from CS/VCC and ROVP Pin.
VCC Capacitor: The VCC capacitor should be as close
as possible to the VCC Pin and GND pin.
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
www.winsemi.com
Tel : +86-755-8250 6288
Fax : +86-755-8250 6299
7/9
WS9442 Product Description
DIP7 Package Dimension
Winsemi
Dimensions in Millimeters
Dimensions in Inches
Symbol
Min
Max
Min
Max
A
B
C
9.00
6.10
3.0
9.50
6.60
3.4
0.354
0.240
0.118
0.058
0.016
0.096
0.374
0.260
0.134
0.062
0.021
0.104
A1
A2
A3
A4
A5
C1
C2
C3
C4
D
1.474
0.41
2.44
1.574
0.53
2.64
0.51TYP
0.99TYP
0.02TYP
0.04TYP
6.6
7.30
0.260
0.287
0.50TYP
0.02TYP
3.00
1.47
7.62
0.24
3.40
1.65
9.3
0.118
0.058
0.300
0.009
0.134
0.065
0.366
0.013
D1
D2
0.32
7.62TYP
0.3TYP
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
www.winsemi.com Tel : +86-755-8250 6288
Fax : +86-755-8250 6299
8/9
WS9442 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
Tel : +86-755-8250 6288
FAX : +86-755-8250 6299
Web Site : www.winsemi.com
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
www.winsemi.com
Tel : +86-755-8250 6288
Fax : +86-755-8250 6299
9/9
相关型号:
©2020 ICPDF网 联系我们和版权申明