WS9841 Product Description WS9841 High Efficiency TRIAC dimmable LED Driver Features Description TRIAC dimmable Internal 300V Power MOSFET driver. The device operates in critical conduction mode and is Critical Conduction Mode Operation suitable for buck, buck-boost or fly-back LED lighting. Ultra Low Operating Current ±5% LED Output Current Accuracy LED Open Protection LED Short Protection Current Sensing Resistor Short Protection VCC Under Voltage Protection Thermal Regulation Function the system reliability, including LED open circuit protection, Available in SOP-8 Package LED short circuit protection, VCC under voltage protection, The WS9841 is a high efficiency TRIAC dimmable LED The WS9841 integrates a 300V power MOSFET. It utilizes patent pending MOSFET driving technique and current sensing method. The operating current of the IC is very low. With very few external components count, it can achieve excellent constant current performance, so the system cost and size are greatly reduced. The WS9841 offers rich protection functions to improve CS resistor short circuit protection and thermal regulation function. Typical Appliction LED Candle Light LED Bulb Other LED Lighting The WS9841 is available in a SOP-8 Package. Typical Application Circuit WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS Copyright@Winsemi Microelectronics Co., Ltd., All right reserved. WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS B1 1222 WS9841 Product Description Pin Definition and Device Marking WS9841 is available in SOP-8 package： WS9841S8P：Product Code A：Product Code X：Internal Code BCY：Internal QC Code YMX：D/C Package Pin Definition Pin name Pin No. Description GND 1 Ground VLN 2 Line Voltage Detecting Pin FB 3 Over Voltage Protection Detecting Pin. VCC 4 Power Supply Pin DRAIN 5,6 Internal HV Power MOSFET Drain. CS 7,8 Current Sense Pin. Connect a sensing 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 2/8 WS9841 Product Description Ordering Information Package Marking Part Number 8-Pin SOP-8, Pb-free WS9841S8P WS9841S8P Absolute Maximum Ratings Symbol Parameter Limit Unit ICC_MAX VCC pin maximum sink current 10 mA DRAIN Internal HV MOSFET drain voltage -0.3~300 V CS Current sense pin input voltage -0.3~6 V FB Over voltage protection detecting pin voltage -0.3~6 V VLN Line voltage detecting pin voltage -0.3~6 V PDMAX Power dissipation (note 2) 0.45 W θJA Thermal resistance (Junction to Ambient) 145 ℃/W TJ Operating junction temperature -40 to 150 ℃ TSTG Storage temperature range -55 to 150 ℃ ESD (note 3) 2 KV 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)/ θ JA and the number listed in the maximum table. Note 3: Human Body mode, 100pF capacitor discharge on 1.5KΩ resistor WINSEMI MICROELECTRONICS www.winsemi.com WINSEMI MICROELECTRONICS Tel : +86-755-8250 6288 WINSEMI MICROELECTRONICS Fax : +86-755-8250 6299 WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS 3/8 WS9841 Product Description Electrical Characteristics Conditions： (Notes 4, 5) (Unless otherwise specified, VCC=15V and TA =25 ℃) Parameter Symbol Condition Min. Typ. Max. Unit VCC Clamp Voltage VCC_CLAMP 1mA 18.8 V VCC Turn On Threshold VCC_ON VCC Rising 14 V VCC Turn off Threshold VCC_UVLO VCC Falling 8.8 V VCC Startup Current IST VCC= VCC-ON - 1V 120 180 uA VCC Operating Current IOP FOP=70KHz 90 150 uA 400 420 mV Supply Voltage Section Current Sense Section Threshold Voltage for Peak VCS_TH Current Limit 380 Threshold Voltage for Peak Current Limit When Output VCS_SHORT Output Short 200 mV TLEB 350 ns TDELAY 200 ns VVLN_TH 3 V Minimum OFF Time TOFF_MIN 2.5 us Maximum OFF Time TOFF_MAX 250 us Maximum On Time TON_MAX 10 us VFB_OVP 1 V 3 Ω Short Leading Edge Blanking Time for Current Sense Switch Off Delay Time Line Voltage Feed Forward Threshold Internal Time Control Section Over Voltage Protection Section FB Over Voltage Protection Threshold MOSFET Section Static Drain-source On-resistance Drain-Source Breakdown Voltage Power MOSFET Drain Leakage Current RDS_ON VGS=15V/IDS=0.5A BVDSS VGS=0V/IDS=250uA IDSS VGS=0V/VDS=300V 300 V 1 uA Thermal section Thermal Regulation TREG Temperature 150 ℃ Note 4: production testing of the chip is performed at 25°C. Note 5: the maximum and minimum parameters specified are guaranteed by test, the typical value are guaranteed by design, characterization and statistical analysis. WINSEMI MICROELECTRONICS www.winsemi.com WINSEMI MICROELECTRONICS Tel : +86-755-8250 6288 WINSEMI MICROELECTRONICS Fax : +86-755-8250 6299 WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS 4/8 WS9841 Product Description Function Description The WS9841 is a high efficiency TRIAC dimmable LED driver IC, specially designed for Buck, Buck-boost or Fly-back LED lighting. The WS9841 integrates a 300V power MOSFET. Utilizing patent pending MOSFET source driving technique, it can achieve excellent constant current performance with very few external components count, so the system cost and size are greatly reduced. Start Up After system powered up, the VCC pin capacitor is charged up by the start up resistor. When the VCC pin voltage reaches the turn on threshold, the internal circuits start operating. The WS9841 integrates an 18.8V zener diode to clamp the VCC voltage. After the output voltage is established, VCC is supplied by the output voltage. Figure 5. Relationship of VLN voltage and VCS_TH Inductor Selection The WS9841 works under inductor current critical conduction mode. When the power MOFET is switched on, the current in the inductor rises up from zero, the on time of the MOSFET can be calculated by the equation: Constant Current Control t on Cycle by Cycle current sense is adopted in WS9841, the CS pin is connected to the current sense comparator, and the voltage on CS pin is compared with the internal 400mV reference voltage. The MOSFET will be switched off when the voltage on CS pin reaches the threshold. Where, L is the inductance value. VIN is the DC bus voltage after the rectifier bridge. The peak inductor current is given by: I PK L IPK VIN VLED VLED is the voltage on the LED. 400 (mA) R CS The maximum on time of the MOSFET is set to 10us internally. Where, RCS is the current sense resistor value. The CS comparator includes a 350ns leading edge blanking time. The VLN pin detects the TRIAC dimmer conducting angle to adjust the LED driver output current. The application After the power MOSFET is switched off, 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: circuit of the VLN pin is shown in Figure 4. When the VLN pin t off voltage is higher than 3V, the threshold for peak current limit VCS_TH decreases linearly as shown in Figure 5. When the VLN pin is not used, it can be grounded or floated. L IPK VLED The inductance can be calculated by the equation: L VLED (VIN VLED ) f IPK VIN 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. Figure 4. VLN pin application circuit WINSEMI MICROELECTRONICS www.winsemi.com WINSEMI MICROELECTRONICS Tel : +86-755-8250 6288 WINSEMI MICROELECTRONICS Fax : +86-755-8250 6299 WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS 5/8 WS9841 Product Description Over Voltage Protection gradually reduced; the output power and thermal dissipation The FB pin is used to detection the output voltage for are also reduced. The system temperature is regulated and over voltage protection (OVP). The FB pin threshold is 1V. the system reliability is improved. The thermal regulation The resistor divider of the FB pin can be set as: temperature is set to 150℃ internally. RFBL 1 RFBL RFBH VOVP PCB Layout The following rules should be followed in WS9841 PCB layout: Where, Bypass Capacitor RFBL is the lower resistor of the resistor divider The bypass capacitor on VCC pin should be as close as RFBH is the higher resistor of the resistor divider possible to the VCC Pin and GND pin. VOVP is the over voltage protection set value. FB Pin For maximizing the system efficiency, the lower resistor The feedback resistor divider should be as close as is recommended to be around 5KΩ. possible to the FB pin, and the trace must keeps away from dynamic node of the inductor and Drain pin trace, otherwise Protection Function the FB pin OVP function might have risk to be mis-triggered by The WS9841 offers rich protection functions to improve the system noise. the system reliability, including LED open/short protection, VLN Pin CS resistor short protection, VCC under voltage protection, The VLN pin resistor divider and capacitor should be as thermal regulation. close as possible to the VLN pin, and the VLN node should be When the LED is open circuit, the system will trigger the away from the high voltage switching nodes. over voltage protection and stop switching. Ground Path When the LED short circuit is detected, the system The power ground path for current sense resistor should works at low frequency (4kHz), and the CS pin turn off be short and wide, and it should be as close as possible to the threshold is reduced to 200mV. So the system power IC GND pin. The IC signal ground for FB resistors should be consumption is very low. At some catastrophic fault condition, connected to the IC GND pin with short traces and should be such as CS resistor shorted or inductor saturated, the away from the power ground path. internal fast fault detection circuit will be triggered, the The Area of Power Loop system stops switching immediately. The area of main current loop should be as small as After the system enters into fault condition, the VCC voltage will decrease until it reaches the UVLO threshold, possible to reduce EMI radiation, such as the power MOSFET, the output diode and the bus capacitor loop. then the system will re-start again. If the fault condition is DRAIN Pin removed, the system will recover to normal operation. To increase the copper area of DRAIN pin for better thermal dissipation. However, too large copper area may Thermal Regulation compromise the EMI performance. The WS9841 integrates thermal regulation function. When the system is over temperature, the output current is WINSEMI MICROELECTRONICS www.winsemi.com WINSEMI MICROELECTRONICS Tel : +86-755-8250 6288 WINSEMI MICROELECTRONICS Fax : +86-755-8250 6299 WINSEMI MICROELECTRONICS WINSEMI MICROELECTRONICS 6/8 WS9841 Product Description SOP8 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 7/8 WS9841 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 8/8