JW1221 FEATURES APPLICATIONS DESCRIPTION TYPICAL APPLICATION. Controller for Adaptive 100/120Hz Current Ripple Removing Circuit

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1 JW Controller for Adaptive 00/0Hz Current Ripple Removing Circuit Parameters Subject to Change Without Notice FEATURES Controller for adaptive 00/0Hz current ripple remover Built-in zener diode for input voltage clamping VG output voltage high to 0V Programmable amplitude of LED current ripple Programmable maximum cathode voltage of LED Programmable maximum LED current Short protection Over temperature protection SOT-6L Package APPLICATIONS LED lighting DESCRIPTION JW is a controller for driving external NMOSFET to remove the 00/0Hz LED current ripple on AC/DC power by a capacitor between VC and GND. The adaptive technology of JW ensures minimum power dissipation on NMOSFET while TYPICAL APPLICATION removing LED current ripple. JW clamps the input voltage on VIN pin by 0V. Only one resistor is needed when the output voltage of AC/DC power is higher than V. JW allows user to setup maximum LED current by the sensing resistor between the source of NMOSFET and ground, which keeps NMOSFET damaged when LED short connected or hot-plug. By sensing the drain voltage of NMOSFET via a resistor between the drain and VLMT pin, JW allows user to setup the maximum cathode voltage of LED string, which could help limit the power dissipation on chip. It is considered that LED is shorted when the cathode voltage of LED is higher than short connecting threshold and remains over 60us JW shuts down NMOSFET when LED is shorted and recovers after ms. JW provides over thermal protection. When the temperature of JW exceed 5, OTP is trigged. JW shuts down NMOSFET until the temperature decrease to 0. Company s Logo is Protected, JW and JOULWATT are Registered Trademarks of JoulWatt technology Inc.

2 JW ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PACKAGE TOP MARKING JUNCTION TEMPERATURE RANGE JWSOTB #PBF JWSOTB #TRPBF SOT-6 40 ºC to 50 ºC JWXXXXPPPP#TRPBF Pb Free Tape and Reel(If TR is not shown, it means Tube) Package Code Part Number PIN CONFIGURATION Top View SOT-6 ABSOLUTE MAXIMUM RATING ) VIN clamp voltage... V VG... 0V VS, VC, VLMT V to 6V Junction Temperature ) )... 50ºC Lead Temperature ºC Storage Temperature ºC to +50 ºC RECOMMENDED OPERATING CONDITIONS Maximum Junction Temperature (T J)...50ºC 4) THERMAL RESISTANCE θ JA θ Jc Note: ) Exceeding these ratings may damage the device. ) The JW guarantees robust performance from -40 C to 50 C junction temperature. The junction temperature range specification is assured by design, characterization and correlation with statistical process controls. ) The JW includes thermal protection that is intended to protect the device in overload conditions. Thermal protection is active when junction temperature exceeds the maximum operating junction temperature. Continuous operation over the specified absolute maximum operating junction temperature may damage the device. 4) Measured on JESD5-7, -layer PCB. SOT-6L ºC /W

3 JW ELECTRICAL CHARATERISTICS VIN = V, TA = 5ºC, unless otherwise stated. Item Symbol Condition Min. Typ. Max. Units VIN clamp voltage V IN_CLP 9 V VIN operation current I IN 5V<VIN<V ma VIN startup voltage threshold V THULVO V VIN startup voltage hysteresis V HYSUVLO 5 V Maximum VG output voltage V VG V VC startup current I VCST VC short to GND when startup ma VLMT reference voltage V VLMTR V Drain voltage of NMOSFET NMOSFET drain voltage limit V D_CLP when voltage limit is V trigged. R LIMIT=00K. Drain voltage of NMOSFET SHORT protection threshold V TH_SHORT when SHORT is trigged V R LIMIT=00K. SHORT protection delay time TSPD 60 us SHORT protection hold time TSPH ms VS voltage limit V VS V PIN DESCRIPTION SOT-6L Name Pin No. VIN Power Supply Description GND Ground VC LED Current Ripple Programming 4 VG NMOSFET GATE driving voltage output 5 VS LED current sensing input 6 VLMT LED Voltage Limit and SHORT protection Programming

4 JW TYPICAL PERFORMANCE CHARACTERISTICS V IN = 90~64V AC, V OUT =75V, I OUT =40mA, COUT= 00µF/00V*, TA = +5 C, unless otherwise noted Pre-driver Output Steady State +JW Output Steady State Efficiency comparison(with and without JW) Efficiency % without Efficiency Vs Vin Vin(V) with JW Open Circuit protection Test Short Circuit Protection Test Continuous power on/off test LED Hot plug VC V/div VO 50V/div VLED- 0V/div ILED 0.A/div 00ms/div 4

5 JW FUNCTIONAL DESCRIPTION JW is a controller for driving external NMOSFET to remove the 00/0Hz LED current ripple on AC/DC power. Theory of Operation The LED string and JW are both supplied by an AC/DC current source. The drain of external NMOSFET is connected to the cathode of LED string. A sensing resistor R SENSE is connected between the source of NMOSFET and GND. The gate is connected to the VG of JW. JW drives NMOSFET to transfer the LED current ripple to voltage ripple on NMOSFET, and ensures the constant voltage across LED string and the current flow through LED string. The scalable adaptive function of JW can regulate the cathode voltage of LED string to minimum to improve the efficiency of the system. Current Ripple Removing The capacitor C C between VC and GND is a integration capacitor. JW transform the voltage on C C to a reference voltage. The current regulator regulates the voltage on R SENSE equal to the reference voltage. The relationship between the voltage on C C and R S is shown as following: V RS = I LED * R SENSE = V VC / 0 C C should be large enough in order to remove the current ripple of the LED string. However, too large capacitor may slow down the dynamic response. NMOSFET is working in the saturation region. JW detects it and charges C C to raise the V VC and I LED, then the output voltage of power supply is reduced, and the voltage drop on NMOSFET decreases. Conversely, when NMOSFET is working in the linear region, LED current regulation loop is open. JW detects it and discharges C C to reduce the V VC and I LED, then the output voltage of power supply is raised, and the LED current regulation loop is close. Drain Voltage of NMOSFET Limit The voltage ripple on the drain of NMOSFET maybe very large when the current ripple is removed, which would bring large power dissipation on chip. The resistor between the drain of NOMSFET and VLMT pin can setup the limit value of drain voltage of NMOSFET. Adaptive Regulation JW control the voltage on C C by monitoring the operation state of external NMOSFET. The efficiency of system is relatively low when 5

6 JW The limit threshold is calculated as below: V limit = V + R LMT * 0uA LED Current Limit The voltage of VS pin is limited to 0.V internally. So the current limitation is 0.V/R S. Current limit can protect the chip when LED is short connected or HOT-PLUG. The function of current limit is higher priority than drain voltage limit. It means that the voltage on drain of NMOSFET is not limited when LED current exceed current limit threshold. LED Short Protection JW detect SHORT by R LMT. When the drain voltage of NMOSFET exceeds the SHORT PROTECTION THRESHOLD and the state holds for more than 60us, JW considers the LED string is SHORT connected, and shut down the external MOSFET. The SHORT state is reset after ms. Over Thermal Protection JW monitors operation temperature. When the temperature is higher than 5, the NMOSFET is shut down until the temperature decrease to 5. PCB Design Guideline. The bypass capacitor of VIN should be placed as close as possible to the VIN pin and GND pin of IC.. JW should be placed far away from the power devices such as MOSFET and SBD.. The area of LED current loop should be as small as possible. MOSFET Selection Recommendation. PDD090, N-Channel MOSFET 00V, 8A, 00mohm, TO5, Potens.. FDS8640, N-Channel MOSFET 50V 7.5A 9.8mohm, SO-8, FAIRCHILD.. FQD8N0V, N-Channel MOSFET 00V, 8A, 40mohm, TO5, FAIRCHILD.. The SHORT PROTECTION THRESHOLD is calculated as: V THSCP = V + R LMT * 40uA 6

7 JW APPLICATION NOTE JW design guide: Because of the 0V zener integrated and the 6V V IN start threshold, the value of R VIN may satisfy the following conditions: V F : the voltage of LED. The maximum voltage of VS pin is V in order to limit the maximum output current especially in the short circuit condition. The value of R S can be calculated as below: 0. I LED : the output current of the pre-driver. When the voltage of LED- reaches V SCP which is set by the R LMT, JW pulls down the VIN then turns off the MOSFET. In order to ensure nothing will be damaged in the short circuit condition, the value of R LMT must satisfy the following conditions: V OVP : V SCP : the output voltage when the pre-driver is open. the threshold of JW short circuit protection. V INSTART : the output voltage of the pre-driver when the VIN of JW is 6V. 4. The value of the capacitor between VC and GND can determine the final amplitude of the current ripple. It should be large enough in order to remove the current ripple of the LED string. However, too large capacitor may slow down the dynamic response. In normal condition, uf or.uf is relatively reasonable. 5. To ensure JW work properly, the R DSON of MOSFET must be less than R S. The MOSFET will endure a large power shorting the output on the moment, so the appropriate package and R DSON of the MOSFET is necessary. 6. When short the LED, there is an overshoot on the drain of the MOSFET. The breakdown voltage of the MOSFET must be higher than V OVP. A diode connected to LED+&LED- can reduce the overshoot when short. 7

8 JW REFERENCE DESIGN Reference: V IN : V OUT : 75V I OUT : 90~60VAC 40mA PF: >0.9 Current ripple: <5% mh 7D47 F SS-5F-A L L R K/0805/5% R C V C 0.uF/75V L 4 0mH 50K/06/5% L 50K/06/5% 0.uF/75V 4 90~64VAC 50/60Hz R mh N R4 R5 4.7uF/50V/06 00K/06/5% 00K/06/5% C6 D M7 D 0R/0805/5% BAV0W C5 M7 D M7 D4 M7 R9 D6 0.uF/60V R0 6K/0805/% R 9.K/0805/% 0.uF/50V/ FB DPWM VCC C 0K/0805/% U VREC COMP GND SNP GATE JW K/06/% 649K/06/% R6 R7 R8 nf/60v R 00K/06/5% 4.7uF/0V/060 C7 00R/0805/5% C4 R4 R7.nF/KV/06 C8 6R/0805/5% M7 Q R.0R/06/% 0.9R/06/% D5 0K/0805/5% Rs SVF7N65F Rs T 5 EDR809 C9 0R/0805/5% R5 C 6 USG D7 7 D8 NC.nF Y5B TYPE "Y" 0pF/KV/06 C0 uf/00v 00V/00uF C + C 00V/00uF R6 00K/06/5% + R C4 uf/00v/0805 5K/06/5% R8 5K/06/5% R NC VIN GND VC C5.uF/6.V/060 JW0 VLMIT VS VG C R0 680K/060/5% 5nF/6V/060 R9 Q FQD8N0 0.5R/06/% D9 N448 LED+ LED- 8

9 JW PACKAGE OUTLINE SOT-6L Unit: mm 9

10 JW IMPORTANT NOTICE Joulwatt Technology Inc. reserves the right to make modifications, enhancements, improvements, corrections or other changes without further notice to this document and any product described herein. Any unauthorized redistribution or copy of this document for any purpose is strictly forbidden. Joulwatt Technology Inc. does not warrant or accept any liability whatsoever in respect of any products purchased through unauthorized sales channel. When using this product, Joulwatt Technology Inc. has no responsibility for any direct or indirect loss caused by the use of the product or attached material. Copyright 04 JW Incorporated. All rights are reserved by Joulwatt Technology Inc. 0