A Product Line of Diodes Incorporated APR343 SECONDARY SIDE SYNCHRONOUS RECTIFICATION CONTROLLER Description Pin Assignments APR343 is a secondary side MOSFET driver for synchronous (Top View) rectification in DCM operation, which integrates the output voltage detection function for primary side control system. The synchronous rectification can effectively reduce the secondary 1 5 DRISR VDET side rectifier power dissipation and provide high performance solution. By sensing MOSFET drain-to-source voltage, APR343 can output ideal drive signal with less external components. It can provide high GND 2 performance solution for 5V output voltage application. Same as AP4341, APR343 detects the output voltage and provides a VCC 3 4 AREF periodical signal when the output voltage is lower than a certain threshold. By fast response to secondary side voltage, APR343 can effectively improve the transient performance of primary side control system. SOT25 The APR343 is available in SOT25 package. Applications Features Adapters/Chargers for Cell/Cordless Phones, ADSL Modems, Synchronous Rectification for DCM Operation Flyback MP3 and Other Portable Apparatus Eliminate Resonant Ring Interference Standby and Auxiliary Power Supplies Fast Detector of Supply Voltage Fewest External Components Totally Lead-free & Fully RoHS Compliant (Notes 1 & 2) Halogen and Antimony Free. Green Device (Note 3) Notes: 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant. 2. See VDET A Product Line of Diodes Incorporated APR343 Pin Descriptions Pin Number Pin Name Function 1 DRISR Synchronous rectification MOSFET Gate drive 2 GND Ground 3 VCC Power supply, connected with system output Program a voltage reference with a resistor from AREF to GND, to enable synchronous rectification 4 AREF MOSFET drive signal 5 VDET Synchronous rectification sense input and dynamic function output, connected with secondary winding Functional Block Diagram VCC 3 V REF I OVP Integrator Dynamic OVP ( V -V )* t DET CC ONP I AREF Counter t ONPDET 4 OSC AREF 1 SRDRIVER DRISR 2 GND 5 VDET 2 of 12 APR343 December 2014 Diodes Incorporated www.diodes.com Document number: DS36884 Rev. 4 - 2 NEW PRODUCT