WS9256ProductDescription High Precision PSR Constant Current LED Driver Features Description Built-in 650V Power MOSFET The WS9256 is a high precision primary-side Constant current control without secondary sense and feedback and regulation controller for LED lighting, it feedback circuit. operates in constant current control mode and is designed ±3% LED current accuracy to work in inductor current discontinuous conduction mode Ultra low operating current to improve efficiency and extremely suitable for flyback convertor under High resistance feedback resistor to improve efficiency universal input, the output power of system should be less Universal input voltage than 24W. LED short and open circuit protection VCC under-voltage protection adopting primary sense and feedback control technology, Feedback loop short circuit protection the secondary sense and feedback circuit is eliminated. Current sense resistor open circuit protection The loop compensation components are also removed Over temperature protection while maintaining stability overall operating conditions. The No external loop compensation component required low component counts and low BOM cost are realized. Available in DIP-7 package The WS9256 integrates 650V power MOSFET. Since Since using the proprietary high accurate current sense method, the WS9256 realizes ±3% accuracy of LED current along with excellent line regulation and load Applications LED bulb light Other LED lighting regulation. The WS9256 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 Copyright@WinsemiMicroelectronics Co.,Ltd.,All rightreserved. WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS 1209 WS9256ProductDescription Pin Configuration and Marking Information WS9256 is offered in DIP7 package, as bellows: WS9256D7P A：Product Code X：Internal Code BCY：Internal Code For QC YMX：D/C Pin Definition Pin No. Pin Name Function Description 1 GND Ground. 2 FB Feedback. This pin detects the output information from auxiliary winding. 3 VCC Power suppl. 4 CS 5,6 Drain Internal high voltage MOSFET drain. 7 NC No connection, must be floated. Current sense. This pin connects a current sense resistor to GND to detect the primary current of transformer. Internal Block Diagram WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS www.winsemi.com Tel : +86-755-8250 6288 WINSEMI MICROELECTRONICS Fax : +86-755-8250 6299 WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS 2/8 WS9256ProductDescription Ordering Information Package Marking Part Number 7-Pin DIP-7, Pb-free WS9256D7P WS9256D7P Recommended Operation Conditions Symbol Parameter Value Unit Fmax Maximumworking frequency 100 khz TA Operation temperature -20~85 ℃ VCC Power supply voltage 10~17.5 V POUT1 Output power(Input voltage230V±15%) <30 W POUT2 Output power(Input voltage85V～265V) <24 W Absolute Maximum Ratings (Note1) symbol paramete limites unit VCC VCC pin input voltage -0.3~20 V FB Feedback pin input voltage -0.3~6 V Drain Internal MOSFET drain voltage -0.3~650 V CS Current sense pin input voltage -0.3~6 V PDMAX Power dissipation (note2) 0.9 W Tjo Operating junction temperature -40~150 ℃ θJA Thermal resistance (Junction to Ambient) 80 ℃/W TSTG Storage temperature range -55~150 ℃ Note 1: Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. Under “recommended operating conditions” the device operation is assured, but some particular parameter may not be achieved. The electrical characteristics table defines the operation range of the device, the electrical characteristics is assured on DC and AC voltage by test program. For the parameters without minimum and maximum value in the EC table, the typical value defines the operation range, the accuracy is not guaranteed by spec. Note 2: The maximum power dissipation decrease if temperature rise, it is decided by TJMAX, θ JA, and environment temperature (TA). The maximum power dissipation is the lower one between PDMAX = (TJMAX - TA)/ θJA and the number listed in the maximum table. WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS www.winsemi.com Tel : +86-755-8250 6288 WINSEMI MICROELECTRONICS Fax : +86-755-8250 6299 WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS 3/8 WS9256ProductDescription Electrical Characteristics (Unless otherwise specified, VCC=8V and TA =25 ℃) Symbol Parameter Test condition Min Typ Max Units 4mA 17.4 18.3 19.4 V 16.1 17.1 18.1 V 8.5 9 9 .5 V 17.9 18.9 19.9 V Supply Voltage Section VDD_CLAMP UVLO_on VDD Clamping Voltage VDD Power Supply VDD Under Voltage UVLO_off Lockout VCCover voltage VCC_OVP protection level Ist Start up current 35 uA Iop Operating current 152 uA Current Sense Section Ipp Primary Peak Current 484 508 531 mV TLEB Lead Edge Blanking 500 ns TDELAY Shutdown Delay 200 ns D_max Maximum Duty Cycle 42 % 420 us 4 us MaxmiumON time 100 us FB voltage sense level 1 V FeedbackInputSection MaximumDemagnetization Toff_max time MinimumDemagnetizationt Toff_min ime Ton_max Vfb Power MOSFET Drain-source leakage Idss Vgs=0V,Vds=650V current BVdss Drain-source breakdown 10 650 voltage Static drain-source Ron V 2.8 on-resistance uA 3.5 Ω Over TemperatureProtection T_comp WINSEMI Thermal Regulation 147 Temperature MICROELECTRONICS WINSEMI MICROELECTRONICS www.winsemi.com Tel : +86-755-8250 6288 WINSEMI MICROELECTRONICS Fax : +86-755-8250 6299 WINSEMI MICROELECTRONICS ℃ WINSEMI MICROELECTRONICS 4/8 WS9256ProductDescription Application Information The ratio of FB upper resistor to lower resistor is The WS9256 is a high performance power switch specially designed for LED lighting, it uses the patent recommended to about 4.0. The FB upper resistor can be set to 300KΩ~750KΩ to improve efficiency of convertor. constant current control technology of WINSEMI. The WS9256 integrates a 650V power MOSFET. The accurate Operation Switching Frequency LED current can be realized without opto-coupler and TL431 The WS9256 is designed to work in discontinuous feedback circuit while minimizing the external component conduction mode and no external loop compensation count, lowering the total bill of material cost. component is required while maintaining stability. The maximum duty cycle is limited to 42%. The maximum Start Up switching frequency should be set to less than 100KHz and The VCC capacitor will be charged through the start-up the minimum switching frequency should be set to more resistor when the system is powered on, once the voltage than 20KHz. The maximum and minimum switching on VCC reaches the start-up threshold, the WS9256 will frequency is limited in WS9256 to ensure the stability of start to operate, and then the VCC is supplied by the system. auxiliary winding. The switching frequency can be set by the formula: Np 2 VLED f 8 Ns 2 Lp I LED Constant Current Control Cycle-by-Cycle current sense is offered in WS9256, the Where, LP is the primary winding inductance of CS is connected to the current sense comparator, and the voltage on CS will be compared with the internal 508mV reference voltage, the MOSFET will be switched off when the voltage on CS reaches the threshold. The output of the transformer. Protection Function The WS9256 has several protection functions. The comparator also includes a 500nS leading edge blanking internal MOSFET will be shut down immediately when the time voltage on VCC reaches the threshold of OVP and the The primary peak current is given by: I P_PK device will not recover until the protection condition is 508 ( mA) RCS removed. A 18V zener diode is designed in the WS9256 to prevent the chip damage from the abnormal situation. The current in LED can be calculated by the equation: I OUT I P_PK 4 The thermal protection circuitry in the WS9256 senses the die temperature after start up, and the thermal protection NP NS threshold is set to 147℃ The system will work in low consumption mode when Where, the output LED short circuit or open circuit is detected. NP: primary winding turns of transformer While the WS9256 continuous to detect output status until NS: secondary winding turns of transformer the LED recover to normal condition, and then the device IP_PK: peak current in MOSFET will be operate in normal mode. Feedback Network PCB Layout The WS9256 senses the output information through the feedback network and the FB threshold voltage is set to 1V. WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS www.winsemi.com Tel : +86-755-8250 6288 WINSEMI The following rules should be followed in WS9256 PCB layout: MICROELECTRONICS Fax : +86-755-8250 6299 WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS 5/8 WS9256ProductDescription Bypass Capacitor NC Pin The bypass capacitor on VCC should be as close as The NC pin must be left floating to satisfy the possible to the VCC pin requirement of creepage distance. Ground Path Drain pin The power ground path for current sense should be To increase the copper area of drain for thermal short, and the power ground path should be separated from consideration. small signal ground path before the negative of the bulk FB Pin capacitor. The feedback divider should be as close as possible to The Area of Power Loop FB Pin and the node must keep away from dynamic node of The area of main current loop should be as small as transformer. possible to reduce EMI radiation, such as the primary current loop, the snubber circuit and the secondary rectifying loop. WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS www.winsemi.com Tel : +86-755-8250 6288 WINSEMI MICROELECTRONICS Fax : +86-755-8250 6299 WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS 6/8 WS9256ProductDescription Package Information DIP7 Package Outline Dimensions Winsemi Dimensions in Millimeters Symbol Min Max Min Max A 9.00 9.50 0.354 0.374 B 6.10 6.60 0.240 0.260 C 3.0 3.4 0.118 0.134 A1 1.474 1.574 0.058 0.062 A2 0.41 0.53 0.016 0.021 A3 2.44 2.64 0.096 0.104 A4 0.51TYP 0.02TYP A5 0.99TYP 0.04TYP C1 6.6 C2 7.30 0.260 0.50TYP 0.287 0.02TYP C3 3.00 3.40 0.118 0.134 C4 1.47 1.65 0.058 0.065 D 7.62 9.3 0.300 0.366 D1 0.24 0.32 0.009 0.013 D2 WINSEMI Dimensions in Inches MICROELECTRONICS 7.62TYP WINSEMI MICROELECTRONICS www.winsemi.com Tel : +86-755-8250 6288 WINSEMI 0.3TYP MICROELECTRONICS Fax : +86-755-8250 6299 WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS 7/8 WS9256ProductDescription 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 www.winsemi.com Tel : +86-755-8250 6288 WINSEMI MICROELECTRONICS Fax : +86-755-8250 6299 WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS 8/8