|
|
PDF WS9254 Data sheet ( Hoja de datos )
| Número de pieza | WS9254 | |
| Descripción | High Precision PSR Constant Current LED Driver | |
| Fabricantes | Winsemi | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de WS9254 (archivo pdf) en la parte inferior de esta página. Total 8 Páginas | ||
|
No Preview Available !
WS9254ProductDescription
High Precision PSR Constant Current LED Driver
Features
Built-in600V Power MOSFET
Constant current control without secondary sense and
feedback circuit.
±3% LED current accuracy
Ultra low operating current to improve efficiency
High resistance feedback resistor to improve efficiency
Universal input voltage
LED short and open circuit protection
VCC under-voltage protection
Feedback loop short circuit protection
Current sense resistor open circuit protection
Over temperature protection
No external loop compensation component required
Available in DIP-7 package
Applications
LED bulb, spot light
OtherLED lighting
Description
The WS9254 is a high precision primary-side
feedback and regulation controller for LED lighting, it
operates in constant current control mode and is designed
to work in inductor current discontinuous conduction mode
and extremely suitable for flyback convertor under
universal input, the output power of system should be less
than 12W.
The WS9254integrates 600V power MOSFET. Since
adopting primary sense and feedback control technology,
the secondary sense and feedback circuit is eliminated.
The loop compensation components are also removed
while maintaining stability overall operating conditions. The
low component counts and low BOM cost are realized.
Since using the proprietary high accurate current
sense method, theWS9254 realizes ±3% accuracy of LED
current along with excellent line regulation and load
regulation.
The WS9254 offers rich protection functions including
LED short circuit protection, LED open circuit protection,
die over-temperature protection, VCC over voltage
protection, VCC under voltage protection and FB short
circuit protection. All the protection features are
auto-recovery.
Typical Application
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
Copyright@WinsemiMicroelectronics Co.,Ltd.,All rightreserved.
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
1208
1 page  
WS9254ProductDescription
Application Information
The WS9254 is a high performance power switch
specially designed for LED lighting, it uses the patent
constant current control technology of WINSEMI. The
WS9254 integrates a 600V power MOSFET. The accurate
LED current can be realized without opto-coupler and TL431
feedback circuit while minimizing the external component
count, lowering the total bill of material cost.
Start Up
The VCC capacitor will be charged through the
start-up resistor when the system is powered on, once the
voltage on VCC reaches the start-up threshold, the WS9254
will start to operate, and then the VCC is supplied by the
auxiliary winding.
Constant Current Control
Cycle-by-Cycle current sense is offered in WS9254, the
CS is connected to the current sense comparator, and the
voltage on CS will be compared with the internal 500mV
reference voltage, the MOSFET will be switched off when
the voltage on CS reaches the threshold. The output of the
comparator also includes a 500nS leading edge blanking
time
The primary peak current is given by:
I P_PK
508 (mA)
RCS
The current in LED can be calculated by the equation:
I OUT
I P_PK
4
NP
NS
Where,
NP: primary winding turns of transformer
NS: secondary winding turns of transformer
IP_PK: peak current in MOSFET
The ratio of FB upper resistor to lower resistor is
recommended to about 4.0. The FB upper resistor can be
set to 300KΩ~750KΩ to improve efficiency of convertor.
Operation Switching Frequency
The WS9254 is designed to work in discontinuous
conduction mode and no external loop compensation
component is required while maintaining stability. The
maximum duty cycle is limited to 42%. The maximum
switching frequency should be set to less than 100KHz and
the minimum switching frequency should be set to more
than 20KHz. The maximum and minimum switching
frequency is limited in WS9254 to ensure the stability of
system.
The switching frequency can be set by the formula:
f
8
Np2 VLED
Ns2 Lp ILED
Where, LP is the primary winding inductance of
transformer.
Protection Function
The WS9254 has several protection functions. The
internal MOSFET will be shut down immediately when the
voltage on VCC reaches the threshold of OVP and the
device will not recover until the protection condition is
removed. A 18V zener diode is designed in the WS9254 to
prevent the chip damage from the abnormal situation.
The thermal protection circuitry in the WS9254 senses
the die temperature after start up, and the thermal protection
threshold is set to 147℃
The system will work in low consumption mode when
the output LED short circuit or open circuit is detected.
While the WS9254 continuous to detect output status until
the LED recover to normal condition, and then the device
will be operate in normal mode.
Feedback Network
The WS9254 senses the output information through the
feedback network and the FB threshold voltage is set to 1V.
PCB Layout
The following rules should be followed in WS9254 PCB
layout:
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
www.winsemi.com Tel : +86-755-8250 6288 Fax : +86-755-8250 6299
WINSEMI MICROELECTRONICS
WINSEMI MICROELECTRONICS
5/8
5 Page | ||
| Páginas | Total 8 Páginas | |
| PDF Descargar | [ Datasheet WS9254.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| WS9252 | High Precision PSR Constant Current LED Driver | Winsemi |
| WS9254 | High Precision PSR Constant Current LED Driver | Winsemi |
| WS9256 | High Precision PSR Constant Current LED Driver | Winsemi |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |