WS9441 Product Description Non-isolated BuckOffline LED Driver Features Critical Conduction Mode Operation Internal 500V Power MOSFET Gate Drive and No Auxiliary Winding ±3% LED Current Accuracy Efficiency up to 93% LED Short Circuit Protection LED Open Circuit Protection Current Sense Resistor Short Protection Description The WS9441 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 WS9441 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 Thermal Regulation Function 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. Applications LED Bulb Lights LED Panel Lights thoroughly solves the problem of light flashing at high LED Strings temperatures. The WS9441 offers full protection functions to The WS9441 adopts intelligent temperature control and improve the system reliability, including LED open circuit protection, LED short circuit protection, CS resistor short circuit protection and thermal regulation function. The WS9441 is available in SOP-7 Package. Typical Application Circuit WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS WINSEMI Copyright@Winsemi Microelectronics Co., Ltd., All right reserved. MICROELECTRONICS WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS 0318 WS9441 Product Description Pin Configuration and Marking Information The WS9441 is available in SOP-7 Package. The top marking is shown as below: Pin Definition Pin No. Name 1 GND 2 ROVP 3 NC 4 VCC 5,6 DRAIN 7 CS Description Ground Over Voltage Protection Setting Pin. Connect a resistor to GND No Connection.Should be hanged out. Power Supply Pin Internal HV Power MOSFET Drain Current Sense Pin. Connect a sense resistor between this pin and GND pin. Block Diagram WINSEMI MICROELECTRONICS www.winsemi.com WINSEMI MICROELECTRONICS Tel : +86-755-8250 6288 WINSEMI MICROELECTRONICS Fax : +86-755-8250 6299 WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS 2/9 WS9441 Product Description Ordering Information Package Marking Part Number 7-Pin DIP-7, Pb-free WS9441S7P WS9441S7P Recommended Operation Conditions Part Number Package Input voltage WS9441S7P SOP7 175VAC-264VAC Maximum output power 150V/120mA 80V/200mA Absolute Maximum Ratings Symbol Parameter Range Unit VDS Internal HV MOSFET drain voltage -0.3~500 V ICC_MAX VCC pin maximum sink current 2.5 mA VROVP LED open circuit protection voltage regulation -0.3~7 V VCS Current sense pin input voltage -0.3~8 V PDMAX Power dissipation SOP7 -0.3~7 V TJ Maximum operating junction temperature 0.9 W TSTG Minimum/Maximum Storage temperature 150 ℃ Note：Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device WINSEMI MICROELECTRONICS www.winsemi.com WINSEMI MICROELECTRONICS Tel : +86-755-8250 6288 WINSEMI MICROELECTRONICS Fax : +86-755-8250 6299 WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS 3/9 WS9441 Product Description Electrical Characteristics (Unless otherwise specified, VCC=15V and TA =25 ℃) Symbol Parameter Conditions Min Typ Max Units 17.8 18.8 19.8 V 14 15 16.2 V 9 9.5 10 V Supply Voltage Section VCC_CLAMP VCC Clamp Voltage UVLO_on Chip Startup Voltage 10mA VDD Under voltage UVLO_off protection Ist Startup Current VCC= 13V 150 220 300 uA Iop Operating Current Fop=70KHz 100 170 250 uA 390 400 410 mV Current Sense Section Threshold Voltage for Vcs_th Peak Current Limit Leading Edge Blanking TLEB Time for Current Sense TDELAY Switch Off Delay Time 350 ns 200 ns 310 us 4.5 us 100 us Internal Time Control Section Toff_max Minimum OFF Time Toff_min Maximum OFF Time Ton_max Maximum On Time Rovp=70k MOSFET Section Static Drain-source Rds_on Vgs=15V,Ids=0.5A On-State Resistance Drain-Source Breakdown BVdss Voltage Drain-Source Leakage Idss Vgs=0V,Ids=250uA 9 Ω 500 V Vgs=0V,Vds=500V Current 11 10 uA Thermal Regulation Section Thermal Regulation TREG WINSEMI 150 Temperature MICROELECTRONICS www.winsemi.com WINSEMI MICROELECTRONICS Tel : +86-755-8250 6288 WINSEMI MICROELECTRONICS Fax : +86-755-8250 6299 WINSEMI MICROELECTRONICS ℃ WINSEMI MICROELECTRONICS 4/9 WS9441 Product Description Function Description comparator, and the voltage on CS pin is compared with the The WS9441 is a high performance non-isolated buck internal 400mV reference voltage. The MOSFET will be converter specially designed for LED lighting. The device switched off when the voltage on CS pin reaches the threshold. integrates a 500V power MOSFET. With the help of advanced constant current control and gate drive technology, The CS comparator includes a 350ns leading edge blanking the time. converter achieves excellent constant current performance with very few external components. It does not The peak inductor current is calculated by the equation: need auxiliary winding for powering the IC or voltage sensing, I PK hence the system size and cost is greatly reduced. Start Up 400 (mA) RCS Where, RCS is the current sense resistor value. After system powered on, the VCC pin capacitor is The current in LED can be calculated by the equation: charged up by the start up resistor. When the VCC pin voltage reaches the turn on threshold, the internal circuits I LED start operating. The WS9441 integrates a 17V ZENER diode I PK (mA) 2 to clamp the VCC voltage. Due to the ultra-low operating Where, IPK is the peak current of the inductor. 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— Freewheeling Diode 264VAC, the start-up resistor can be calculated by the equation: RST The diode will bear the reverse voltage equal to the input voltage when the MOSFET is on. A 600V diode was V IN _ MIN 1.414 I ST _ MAX 176 1.414 910 K 270 Two resistors in 1206 size SMD can be used in series. VCC Capacitor Selection 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. 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. Input Electrolytic Capacitor 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 A 1uF or above capacitor can be used in Vcc. If following empirical equations: 90Vac~264Vac: 1W output uses1uF buck electrolytic selecting MLCC, the material of X7R will be used to satisfy the stability of the capacity under high temperatures. Due to capacitor; 176Vac~264Vac: 1W output uses 0.5uF buck electrolytic external damage resulted from small volume and brittle texture of MLCC, the Vcc is easy to leakage currents, which capacitor. will make the WS9441 unable to start. Strict control measures are taken in its layout and productive process. Output Capacitor Electrolytic capacitor is recommended to be used. Its Constant Current Control stable capacitance can improve the efficiency of power supply, The WS9441 utilizes proprietary current control method. the LED ripple current and luminous efficiency. Vovp voltage should be considered in output capacitor It can achieve precise LED output current with a few external components. Cycle by Cycle current sense is adopted in pressure. WS9441, the CS pin is connected to the current sense WINSEMI MICROELECTRONICS www.winsemi.com WINSEMI MICROELECTRONICS Tel : +86-755-8250 6288 WINSEMI MICROELECTRONICS Fax : +86-755-8250 6299 WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS 5/9 WS9441 Product Description Inductor Selection current is gradually reduced; the output power and thermal The WS9441 works in a inductor critical current dissipation are also reduced. The system temperature is conduction mode. When the power MOFET is switched on, regulated and the system reliability is improved. The thermal the current in the inductor rises up from zero. The on time of regulation temperature is set to 150℃ internally. the MOSFET can be calculated by the equation: t on Over Voltage Protection L I PK VIN VLED The over voltage protection of the WS9441 can be programmed by the ROVP pin resistor. The ROVP pin voltage Where, is 0.5V. L is the inductance value, When the LED is open circuit, the period of the output IPK is the peak current of the inductor, VIN is the DC bus voltage after the rectifier bridge, voltage increases gradually, the demagnetization time gets shorter. The demagnetization time at OVP---- Tovp can be 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 calculated by the open circuit protection voltage by the equation: reaches zero, the power MOSFET is turned on again by IC Tovp internal logic. The off time of the MOSFET is given by the equation: toff L I PK VLED Where， Vcs is the CS pin turn off threshold (0.4V); The inductance can be calculated by the equation: L L V CS R CS V OVP VLED (VIN VLED ) f I PK VIN Vovp is the open circuit protection voltage. And then the Rovp resistor value can be calculated by the equation: 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 It is suggested that the open circuit protection voltage is set at or above 1.5 times maximum load voltage. maximum switching frequency is set at highest input voltage. The minimum and maximum off time of WS9441 is set at Protection Function 4.5us and 310us, respectively. Referring to the equation of The WS9441 offers rich protection functions to improve Toff calculation, if the inductance is too small, the Toff may be the system reliability, including LED open/short protection, CS smaller than the minimum off time, the system will operate in resistor short protection, VCC under voltage protection, discontinuous conduction mode and the output current will thermal regulation. When the LED is open circuit, the system be smaller than the designed value. If the inductance is too will trigger the over voltage protection and stop switching. large, the Toff may be larger than the maximum off time, the When the LED short circuit is detected, the system works at system will operate in continuous conduction mode and the low frequency and the CS pin turnoff threshold is reduced. So output current will be higher than the designed value. So it is the system power consumption is very low. At some abnormal important to choose a proper inductance. fault condition, such as CS resistor shorted or inductor saturation, the internal fast fault detection circuit will be Thermal Regulation triggered, the system stops switching immediately. The WS9441 integrates thermal regulation function. After the system enters into faulty condition, the VCC When the system is under higher temperature, the output voltage will decrease until it reaches the UVLO threshold, then WINSEMI MICROELECTRONICS www.winsemi.com WINSEMI MICROELECTRONICS Tel : +86-755-8250 6288 WINSEMI MICROELECTRONICS Fax : +86-755-8250 6299 WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS 6/9 WS9441 Product Description the system will restart again. If the fault condition is removed, Ground Path: The power ground path for current sense the system will recover to normal operation. resistor should be short, and the power ground path should be separated from small signal ground path before connecting to Line Voltage Compensation The WS9441 integrates line voltage compensation the negative node of the bulk capacitor. The Area of Power Loop: The area of main current loop function, which makes LED current remain unchanged in the should be as small as possible to reduce EMI radiation. And it range of full voltage with good line regulation and current should be away from diodes and other heating components. accuracy. 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 WS9441 PCB DRAIN PIN: The copper area of DRAIN pin can be increased for better thermal dissipation. And it should be away layout: VCC Capacitor: The VCC capacitor should be as close from CS/VCC and ROVP Pin. as possible to the VCC Pin and GND pin. WINSEMI MICROELECTRONICS www.winsemi.com WINSEMI MICROELECTRONICS Tel : +86-755-8250 6288 WINSEMI MICROELECTRONICS Fax : +86-755-8250 6299 WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS 6/9 WS9441 Product Description SOP7 Package Dimension Winsemi Dimensions in Millimeters Symbol Dimensions in Inches Min Max Min Max A 4.70 5.10 0.185 0.201 B 3.70 4.10 0.146 0.161 C 1.30 1.50 0.051 0.059 A1 0.35 0.48 0.014 0.019 A2 1.27TYP 0.05TYP A3 0.345TYP 0.014TYP B1 5.80 B2 6.20 0.228 5.00TYP 0.244 0.197TYP C1 0.55 0.70 0.022 0.028 C2 0.55 0.70 0.022 0.028 C3 0.05 0.225 0.002 0.009 C4 0.203TYP 0.008TYP D 1.05TYP 0.041TYP D1 WINSEMI 0.40 MICROELECTRONICS www.winsemi.com WINSEMI 0.80 MICROELECTRONICS Tel : +86-755-8250 6288 WINSEMI 0.016 MICROELECTRONICS Fax : +86-755-8250 6299 WINSEMI MICROELECTRONICS 0.031 WINSEMI MICROELECTRONICS 8/9 WS9441 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 www.winsemi.com WINSEMI MICROELECTRONICS Tel : +86-755-8250 6288 WINSEMI MICROELECTRONICS Fax : +86-755-8250 6299 WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS 6/9