RT7310 Phase-Cut Dimmable Primary-Side Regulation LED Driver Controller with Active PFC General Description Features Supporting Phase-Cut Dimmers The RT7310 is a high power factor constant current Tight LED Current Regulation LED driver which is optimized for the compatibility with No Opto-Coupler and TL431 Required phase-cut dimmers. It supports high power factor Power Factor Correction (PFC) across a wide range of line voltages, and it drives the Quasi-Resonant converter in the Quasi-Resonant (QR) mode to achieve Maximum/Minimum Switching Frequency higher efficiency. By using Primary Side Regulation Clamping (PSR), RT7310 controls the output current accurately Maximum/Minimum On-Time Limitation without a shunt regulator and an opto-coupler at the Wide VDD Range (up to 25V) secondary side, reducing the external component count, Multiple Protection Features : the cost, and the volume of the driver board. LED Open-Circuit Protection The RT7310 supports phase-cut dimmers, including LED Short-Circuit Protection leading-edge (TRIAC) and trailing-edge dimmers. Output Diode Short-Circuit Protection RT7310 embeds comprehensive protection functions for VDD Under-Voltage Lockout robust designs, including LED open circuit protection, VDD Over-Voltage Protection LED short circuit protection, output diode short-circuit Over-Temperature Protection protection, VDD Under-Voltage Lockout (UVLO), VDD Cycle-by-Cycle Current Limitation Over-Voltage Protection (OVP), Over-Temperature Protection (OTP), and cycle-by-cycle current limitation. Application Phase-Cut Dimmable LED luminaries Simplified Application Circuit Flyback Converter Tapped-Inductor Buck-Boost Converter L1 D BD TX1 L1 BD TX OUT 1 V Line OUT- Line V OUT+ COUT N2 RDMR2 D R R OUT DMR2 COUT ST1 RST1 NP NS V OUT+ C Q2 X C N CX Q2 RT7310 V M 1 C OUT- M RDMR1 CDMR R C DMR1 DMR D RT7310 Q1 Z DZ GD Neutral Neutral RPC D ST Q1 D GD ST CS RPC CS VDD R VDD CS R CVDD CS C VDD COMP GND CCOMP ZCD COMP GND R C ZCD2 COMP ZCD R ZCD2 N A N 3 R ZCD1 D AUX RZCD1 D AUX Copyright 2014 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. DS7310-00 October 2014 www.richtek.com 1 RT7310 Ordering Information Marking Information 3K= : Product Code RT7310 DNN : Date Code 3K=DNN Package Type E : SOT-23-6 Lead Plating System G : Green (Halogen Free and Pb Free) Pin Configuration (TOP VIEW) Note : COMP ZCD CS Richtek products are : RoHS compliant and compatible with the current 6 5 4 requirements of IPC/JEDEC J-STD-020. 2 3 Suitable for use in SnPb or Pb-free soldering processes. GND GD VDD SOT-23-6 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 for detecting demagnetization time of the magnetizing inductance. 6 COMP Compensation Node. Output of the internal trans-conductance amplifier. Copyright 2014 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. www.richtek.com DS7310-00 October 2014 2