RT7302 Primary-Side-Regulation Dimmable LED Driver Controller with Active PFC General Description Features Tight LED Current Regulation The RT7302 is a constant current LED driver with active No Opto-Coupler and TL431 Required power factor correction. It supports high power factor Power Factor Correction (PFC) across a wide range of line voltages, and it drives the Compatible with PWM Dimming converter in the Quasi-Resonant (QR) mode to achieve Built-in HV Start-up Device higher efficiency. By using Primary Side Regulation (PSR), Quasi-Resonant the RT7302 controls the output current accurately without Maximum/Minimum Switching Frequency a shunt regulator and an opto-coupler at the secondary Clamping side, reducing the external component count, the cost, Input Voltage Feed-Forward Compensation and the volume of the driver board. Maximum/Minimum On-Time Limitation The RT7302 is designed to be compatible with PWM Wide VDD Voltage Range (up to 25V) Dimming. The output current can be modulated by the Multiple Protection Features duty ratio of the external PWM dimming signal. LED Open-Circuit Protection An in-house design High Voltage (HV) start-up device is LED Short-Circuit Protection integrated in the RT7302 to minimize the power loss and Output Diode Short-Circuit Protection shorten the start-up time. VDD Under-Voltage Lockout VDD Over-Voltage Protection The RT7302 embeds comprehensive protection functions Over-Temperature Protection for robust designs, including LED open-circuit protection, Cycle-by-Cycle Current Limit LED short-circuit protection, output diode short-circuit RoHS Compliant and Halogen Free protection, VDD Under-Voltage Lockout (UVLO), VDD Over-Voltage Protection (VDD OVP), Over-Temperature Protection (OTP), and cycle-by-cycle current limitation. Applications AC/DC LED Lighting driver Simplified Application Circuit Flyback Converter Buck-Boost Converter D TX1 OUT BD BD Line Line V V OUT+ OUT- C C TX1 OUT OUT D OUT CSIN RM1 RHV C R R SIN M1 HV RT7302 V RT7302 V OUT+ OUT- HV Q1 HV Q1 GD GD Neutral Neutral MULT MULT RPC RPC R M2 R M2 CS CS R COMP CS R CS COMP C D COMP AUX CCOMP DAUX GND VDD GND VDD ZCD CVDD ZCD R C ZCD1 VDD R ZCD1 R ZCD2 R ZCD2 Copyright 2013 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. DS7302-01 December 2013 www.richtek.com 1RT7302 Ordering Information Marking Information RT7302 RT7302GS : Product Number RT7302 Package Type YMDNN : Date Code GSYMDNN S : SOP-8 Lead Plating System G : Green (Halogen Free and Pb Free) Note : Pin Configurations Richtek products are : (TOP VIEW) RoHS compliant and compatible with the current require- 8 ments of IPC/JEDEC J-STD-020. HV VDD 2 7 GND GD Suitable for use in SnPb or Pb-free soldering processes. 3 6 COMP CS 4 5 MULT ZCD SOP-8 Functional Pin Description Pin No. Pin Name Pin Function 1 HV High Voltage Input for Startup. 2 GND Ground of the Controller. 3 COMP Compensation Node. Output of the internal trans-conductance amplifier. Input for Line Voltage Signal. This pin is used to sense the line voltage by resistor divider 4 MULT to achieve dimming function. Zero Current Detection Input. This pin is used to sense the voltage at auxiliary winding of 5 ZCD the transformer for detecting demagnetization time of the magnetizing inductance. 6 CS Current Sense Input. Connect this pin to the current sense resistor. 7 GD Gate Driver Output for External Power MOSFET. Supply Voltage (V ) Input. The controller will be enabled when V exceeds V DD DD TH ON 8 VDD and disabled when V is lower than V . DD TH OFF Copyright 2013 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. www.richtek.com DS7302-01 December 2013 2