RT7304A Primary-Side Regulation LED Driver Controller with Active-PFC General Description Features The RT7304A is a constant current LED driver with Tight LED Current Regulation active power factor correction. It supports high power No Opto-Coupler and TL431 Required factor across a wide range of line voltages, and it drives Power Factor Correction (PFC) the converter in the Quasi-Resonant (QR) mode to Quasi-Resonant achieve higher efficiency. By using Primary Side Maximum/Minimum Switching Frequency Regulation (PSR), the RT7304A controls the output Clamping current accurately without a shunt regulator and an Maximum/Minimum on-Time Limitation opto-coupler at the secondary side, reducing the Wide VDD Range (up to 34V) external component count, the cost, and the volume of THD Optimization the driver board. Input-Voltage Feed-Forward Compensation Multiple Protection Features The RT7304A embeds comprehensive protection LED Open-Circuit Protection functions for robust designs, including LED open-circuit LED Short-Circuit Protection protection, LED short-circuit protection, output diode Output Diode Short-Circuit Protection short-circuit protection, VDD Under-Voltage Lockout VDD Under-Voltage Lockout (UVLO), VDD Over-Voltage Protection (VDD OVP), VDD Over-Voltage Protection Over-Temperature Protection (OTP), and cycle-by-cycle Over-Temperature Protection current limitation. Cycle-by-Cycle Current Limitation Applications AC/DC LED Lighting Driver Simplified Application Circuit Buck-Boost Converter TX1 BD V OUT- Line C IN C OUT R ST D OUT Neutral VDD V OUT+ Q1 C RT7304A GD VDD R PC COMP CS R C CS COMP ZCD GND D AUX R ZCD1 R ZCD2 Copyright 2016 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. DS7304A-00 July 2016 www.richtek.com 1 RT7304A Ordering Information Pin Configurations (TOP VIEW) RT7304A Package Type COMP ZCD CS E : SOT-23-6 6 5 4 Lead Plating System G : Green (Halogen Free and Pb Free) 2 3 GND VDD GD Note : Richtek products are : SOT-23-6 RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020. Suitable for use in SnPb or Pb-free soldering processes. Marking Information 4T= : Product Code DNN : Date Code 4T=DNN Functional Pin Description Pin No. Pin Name Pin Function 1 GND Ground of the Controller. Supply Voltage (V ) Input. The controller will be enabled when V exceeds DD DD 2 VDD V and disabled when V is lower than V . TH ON DD TH OFF 3 GD Gate Driver Output for External Power MOSFET. 4 CS Current Sense Input. Connect this pin to the current sense resistor. Zero Current Detection Input. This pin is used to sense the voltage at auxiliary 5 ZCD winding of the transformer. 6 COMP Compensation Node. Output of the internal trans-conductance amplifier. Copyright 2016 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. www.richtek.com DS7304A-00 July 2016 2