WS9441P 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 WS9441P 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 WS9441P 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 Thermal Regulation Function IC is 200uA, so it doesn’t need the auxiliary winding for supplying External PWM Dimming the chip, thus simplifying design and reducing cost. The WS9441P adopts intelligent temperature control and Applications thoroughly solves LED Bulb Lights temperatures. It integrates an external dimming pin which inputs LED Panel Lights PWM signal and can dim by changing the duty cycle of the PWM LED Strings signal. The WS9441P offers full protection functions to improve the problem of light flashing at high the system reliability, including LED open circuit protection, LED short circuit protection, CS resistor short circuit protection and thermal regulation function. The WS9441P is available in SOP-7 Package. Typical Application Circuit WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS Copyright@Winsemi Microelectronics Co., Ltd., All right reserved. WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS 0318 WS9441P Product Description Pin Configuration and Marking Information The WS9441P is available in SOP-7 Package. The top marking is shown as below: WS9441PS7P：Product Code A：Product Code X：Internal Code BCY：Internal Code For QC YMX：D/C Pin Definition Pin No. Name Description 1 GND 2 ROVP 3 DIM Dinmming Pin.Must be floated when not in use. 4 VCC Power Supply Pin 5,6 DRAIN 7 CS Ground Over Voltage Protection Setting Pin. Connect a resistor to GND Internal HV Power MOSFET Drain Current Sense Pin. Connect a sense resistor between this pin and the 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 WS9441P Product Description Ordering Information Package Marking Part Number 7-Pin DIP-7, Pb-free WS9441PS7P WS9441PS7P Recommended Operation Conditions Part Number Package Input voltage WS9441PS7P 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 WS9441P 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 DIM Dimming Section DIM Square Wave High VH_DIM Level DIM Square Wave Low VL_DIM Level DIM Square Signal f_DIM Frequency 1 3 5 V -300 0 400 mV 0.1 0.5 5 KHZ 9 11 Ω 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 500 V Vgs=0V,Vds=500V Current 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 WS9441P Product Description Function Description adopted in WS9441P, the CS pin is connected to the current The WS9441P is a high performance non-isolated buck sense comparator, and the voltage on CS pin is compared converter specially designed for LED lighting. The device with the internal 400mV reference voltage. The MOSFET will integrates a 500V power MOSFET. With the help of advanced constant current control and gate drive technology, be switched off when the voltage on CS pin reaches the the threshold. The CS comparator includes a 350ns leading edge converter achieves excellent constant current performance with very few external components. It does not need auxiliary winding for powering the IC or voltage sensing, blanking time. The peak inductor current is calculated by the equation: hence the system size and cost is greatly reduced. I PK Start Up After system powered on, the VCC pin capacitor is 400 (mA) RCS Where, RCS is the current sense resistor value. charged up by the start up resistor. When the VCC pin The current in LED can be calculated by the equation: voltage reaches the turn on threshold, the internal circuits start operating. The WS9441P integrates a 17V ZENER I LED diode to clamp the VCC voltage. Due to the ultra-low operating current, the auxiliary winding is not needed to supply the IC. I PK (mA) 2 Where, IPK is the peak current of the inductor. 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 Freewheeling Diode The diode will bear the reverse voltage equal to the equation: input voltage when the MOSFET is on. A 600V diode was RST 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. 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. VCC Capacitor Selection The Vcc capacitor is used to bypass noise to IC, so that Input Electrolytic Capacitor Input voltage should be considered in to the capacitor to assure its stable operation, and should be as close as pressure, and the common value is 400V. possible to the chip. In general, the capacity design can be calculated by the A 1uF or above capacitor can be used in Vcc. If following empirical equations: selecting MLCC, the material of X7R will be used to satisfy the stability of the capacity under high temperatures. Due to 90Vac~264Vac: 1W output uses1uF buck electrolytic capacitor; external damage resulted from small volume and brittle texture of MLCC, the Vcc is easy to leakage currents, which 176Vac~264Vac: 1W output uses 0.5uF buck electrolytic capacitor. will make the WS9441P 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 WS9441P utilizes proprietary current control the LED ripple current and luminous efficiency. method. It can achieve precise LED output current with a few external components. Cycle by Cycle current sense is WINSEMI MICROELECTRONICS www.winsemi.com WINSEMI MICROELECTRONICS Tel : +86-755-8250 6288 WINSEMI Vovp voltage should be considered in output capacitor pressure. MICROELECTRONICS Fax : +86-755-8250 6299 WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS 5/9 WS9441P Product Description L External PWM Dimming VLED (VIN VLED ) f I PK VIN The WS9441P integrates an external dimming pin which inputs PWM signal and can dim by changing the duty cycle of the PWM signal. The testing dimmable curve of a 80V/220mA driver under 175~264Vac application is shown 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. as below: The minimum and maximum off time of WS9441P 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. The duty cycle of the PWM signal Thermal Regulation The WS9441P integrates thermal regulation function. Inductor Selection The WS9441P works in a inductor critical current conduction mode. When the power MOFET is switched on, the current in the inductor rises up from zero. The on time of When the system is under higher temperature, the output current is gradually reduced; the output power and thermal dissipation are also reduced. The system temperature is regulated and the system reliability is improved. The thermal the MOSFET can be calculated by the equation: regulation temperature is set to 150℃ internally. L I PK t on VIN VLED Over Voltage Protection Where, The over voltage protection of the WS9441P can be L is the inductance value, programmed by the ROVP pin resistor. The ROVP pin voltage IPK is the peak current of the inductor, is 0.5V. VIN is the DC bus voltage after the rectifier bridge, VLED is the voltage on the LED. When the LED is open circuit, the period of the output voltage increases gradually, the demagnetization time gets 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 shorter. The demagnetization time at OVP---- Tovp can be calculated by the open circuit protection voltage by the equation: equation: toff Tovp L I PK VLED L V CS R CS V OVP Where， The inductance can be calculated by the equation: Vcs is the CS pin turn off threshold (0.4V); Vovp is the open circuit protection voltage. WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS WS9441P Product Description And then the Rovp resistor value can be calculated by the equation: Rovp 120 7 . 67 * Tovp * 10 6 （KΩ） PCB Layout It is suggested that the open circuit protection voltage is set at or above 1.5 times maximum load voltage. The following rules should be followed in WS9441P PCB layout: VCC Capacitor: The VCC capacitor should be as close Protection Function The WS9441P 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, as possible to the VCC Pin and GND pin. 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 trigger the over voltage protection and stop The Area of Power Loop: The area of main current loop switching. When the LED short circuit is detected, the system should be as small as possible to reduce EMI radiation. And it works at low frequency and the CS pin turnoff threshold is should be away from diodes and other heating components. reduced. So the system power consumption is very low. At ROVP PIN: The ROVP resistor should be as close as some abnormal fault condition, such as CS resistor shorted possible to the ROVP Pin to increase its resistance to prevent or inductor saturation, the internal fast fault detection circuit from the interference. will be triggered, the system stops switching immediately. After the system enters into faulty condition, the VCC voltage will decrease until it reaches the UVLO threshold, 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. then the system will restart again. If the fault condition is removed, the system will recover to normal operation. Line Voltage Compensation The WS9441P integrates line voltage compensation function, which makes LED current remain unchanged in the range of full voltage with good line regulation and current accuracy. WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS WS9441P 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 WS9441P 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 9/9