JW1220 Datasheet
JW1220
Controller for Adaptive 100/120Hz
Current Ripple Removing Circuit
Parameters Subject to Change Parameters Subject to Change Without Notice
FEATURE FEATURES S
Controller for adaptive 100/120Hz current
ripple remover
Built-in zener diode for input voltage
clamping
VG output voltage high to 10V
Programmable amplitude of LED current
ripple
Programmable maximum cathode voltage of
LED
Programmable maximum LED current Short protection
Over temperature protection SOT23-6L Package
APPLICATIONS APPLICATIONS
LED lighting
DESCRIPTION
JW1220 is a controller for driving external NMOSFET to remove the 100/120Hz LED current ripple on AC/DC power by a capacitor between VC and GND.
The adaptive technology of JW1220 ensures
minimum power dissipation on NMOSFET while removing LED current ripple.
JW1220 clamps the input voltage on VIN pin by 30V. Only one resistor is needed when the output voltage of AC/DC power is higher than 30V.
JW1220 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, JW1220 allows user to setup the maximum cathode voltage of LED string, which could help limit the power dissipation on chip.
It’s considered that LED is shorted when the cathode voltage of LED is higher than short connecting threshold and remains over 0.5 second. JW1220 shuts down NMOSFET when LED is shorted.
JW1220 provides over thermal protection. When OTP is trigged, the current removing function is
blocked, and then the temperature decreases.
TYPICAL APPLICATION TYPICAL APPLICATION
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ORDER INFORMATION ORDER INFORMATION
PART MARKING
PACKAGE DESCRIPTION
Top Marking
Package Form JW1220
SOT23-6L
JW1220
Tape and reel packaging :
3000 pieces/tape
PIN CONFIGURATION PIN CONFIGURATION
Top View
SOT23-6L
ABSOLUTE MAXIMUM RATING
VIN clamp voltage ............................. 30V VG ........................................ 20V VS, VC, VLMT ........................ -0.3V ~ 6V Junction Temperature
2) 3)
..................... 150oC
Lead Temperature ......................... 260 oC Storage Temperature ............ －65 oC ~ +150 oC
RECOMMENDED OPERATIN RECOMMENDED OPERATING CONDITIONS G CONDITIONS G CONDITIONS
Maximum Junction Temperature (T J )...........150oC
THERMAL THERMAL RESISTANCE θ
JA JA
θJ c
SOT23-6L ...................... 50 ...10℃/W
Note ：
1) Exceeding these ratings may damage the device.
2) The JW1220 guarantees robust performance from -40°C to 150°C junction temperature. The junction temperature range specification is assured by design, characterization and correlation with statistical process controls.
3) The JW1220 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 JESD51-7, 4-layer PCB.
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ELECTRICAL ELECTRICAL CHARATERISTICS CHARATERISTICS CHARATERISTICS
VIN = 12V, TA = 25oC, unless otherwise stated.
Item
Symbol
Condition Min.
Typ.
Max.
Units
VIN clamp voltage V IN_CLP
33 35 37 V VIN operation current I IN 5V 9.5 10 10.5 V VC startup current I VCST VC short to GND when startup 0.7 0.8 0.9 mA VLMT reference voltage V VLMTR 1.95 2 2.05 V NMOSFET drain voltage limit V D_CLP Drain voltage of NMOSFET when voltage limit is trigged. R LIMIT =100K. 3.4 4 4.6 V SHORT protection threshold V TH_SHORT Drain voltage of NMOSFET when SHORT is trigged. R LIMIT =100K. 5 6 7.5 V SHORT protection delay TSP 0.5 s VS voltage limit V VS 0.18 0.2 0.22 V PIN DESCRIPTION SOT23SOT23--6L Pin No. Name Description 1 VIN Power Supply 2 GND Ground 3 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 ying kang ke ji you xian gong si chenS:138******** qq:2995984049 TYPICAL PERFORMANCE CHARACTERISTICS TYPICAL PERFORMANCE CHARACTERISTICS V IN = 90~264V AC , V OUT =75V, I OUT =240mA, COUT= 100μF/100V*2, TA = +25°C, unless otherwise noted Pre-driver Output Steady State +JW1220 Output Steady State Efficiency comparison(with and without JW1220) Open Circuit protection Test Short Circuit Protection Test Continuous power on/off test LED Hot plug 86 87 88 89 90 91 92 90 110130150170190210230250 E f f i c i e n c y % Vin(V) Efficiency VS Vin without with JW1220 ying kang ke ji you xian gong si chenS:138******** qq:2995984049 FUNCTIONAL DESCRIPTION FUNCTIONAL DESCRIPTION JW1220 is a controller for driving external NMOSFET to remove the 100/120Hz LED current ripple on AC/DC power. Theory of Operation The LED string and JW1220 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 JW1220. JW1220 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 JW1220 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. JW1220 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 / 10 C C should be large enough in order to remove the current ripple of the LE D string. However, too large capacitor may slow down the dynamic response. Adaptive Regulation JW1220 control the voltage on C C by monitoring the operation state of external NMOSFET. The efficiency of system is relatively low when NMOSFET is working in the saturation region. JW1220 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. JW1220 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. ying kang ke ji you xian gong si chenS:138******** qq:2995984049 The limit threshold is calculated as below: V limit= 2V + R LMT * 20uA LED Current Limit The voltage of VS pin is limited to 0.2V internally. So the current limitation is 0.2V/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 JW1220 detect SHORT by R LMT. When the drain voltage of NMOSFET exceeds the SHORT PROTECTION THRESHOLD and the state holds for more than 0.5 second, JW1220 considers the LED string is SHORT connected, and shut down the external MOSFET. The shut down state is latched until system restart. The SHORT PROTECTION THRESHOLD is calculated as: V THSCP = 2V + R LMT * 40uA Over Thermal Protection JW1220 monitors operation temperature. When the temperature is higher than 135℃, the current ripple removing function is blocked, which could help NMOFSET cooling. Over thermal protection will not be reset until the system restart. PCB Design Guideline 1. The bypass capacitor of VIN should be placed as close as possible to the VIN pin and GND pin of IC. 2. JW1220 should be placed far away from the power devices such as MOSFET and SBD. 3. The area of LED current loop should be as small as possible. ying kang ke ji you xian gong si chenS:138******** qq:2995984049 APPLICATION NOTE APPLICATION NOTE JW1220 design guide: 1. Because of the 30V zener integrated and the 4.6V V IN start threshold, the value of R VIN may satisfy the following conditions: ????? ???4.6? 0.5?? V F : the voltage of LED 2. The maximum voltage of VS pin is 2V in order to limit the maximum output current especially in the short circuit condition. The value of R S can be calculated as below: ??? 0.2? ???? I LED : the output current of the pre-driver 3. When the voltage of LED- reaches V SCP which is set by the R LMT , JW1220 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: ??????????????? ???????????????????0.5???4.6? ?????2??40??????? V OVP : the output voltage when the pre-driver is open. V SCP : the threshold of JW1220 short circuit protection. V INSTART : the output voltage of the pre-driver when the VIN of JW1220 is 4.6V. 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, 1uF or 2.2uF is relatively reasonable. 5. To ensure JW1220 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. ying kang ke ji you xian gong si chenS:138******** qq:2995984049 REFERENCE DESIGN REFERENCE DESIGN Reference： V IN: 90~260VAC PACKAGE OUTLINE PACKAGE OUTLINE 0.45 ying kang ke ji you xian gong si chenS:138******** qq:2995984049