 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
WS9254D7P Datasheet(PDF) 5 Page - Shenzhen Winsemi Microelectronics Co., Ltd |
|
||||||||||||||||||||||||||||||
WS9254D7P Datasheet(HTML) 5 Page - Shenzhen Winsemi Microelectronics Co., Ltd |
|
|
5 / 8 page  WS9254ProductDescription WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS www.winsemi.com Tel : +86-755-8250 6288 Fax : +86-755-8250 6299 5/8 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: ) ( 508 P_PK mA R I CS The current in LED can be calculated by the equation: S P OUT N N I I 4 P_PK Where, NP: primary winding turns of transformer NS: secondary winding turns of transformer IP_PK: peak current in MOSFET Feedback Network The WS9254 senses the output information through the feedback network and the FB threshold voltage is set to 1V. 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: LED LED I Lp Ns V Np f 2 2 8 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. PCB Layout The following rules should be followed in WS9254 PCB layout: |
Similar Part No. - WS9254D7P |
|
Similar Description - WS9254D7P |
|
|
|
Link URL |
| Privacy Policy |
| ALLDATASHEET.NET |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
