IRAUDAMP6

IRAUDAMP6 250W/8 x 2 Channel Class D Audio Power Amplifier Using the IRS20957S and IRF6785 By Jun Honda, Jorge Cerezo and Liwei Zheng CAUTION: International Rectifier suggests the following guidelines for safe operation and handling of IRAUDAMP6 Demo board Always wear safety glasses whenever operating Demo Board Avoid physical contact with exposed metal surfaces when operating Demo Board Turn off Demo Board when placing or removing measurement probes www.irf.com Page 1 of 46 IRAUDAMP6 REV 1.0 TABLE OF CONTENTS PAGE INTRODUCTION............................................................................................................................................... 3 SPECIFICATIONS............................................................................................................................................ 3 CONNECTION SETUP..................................................................................................................................... 5 CONNECTOR DESCRIPTION ......................................................................................................................... 6 TEST PROCEDURES....................................................................................................................................... 6 PERFORMANCE AND TEST GRAPHS .......................................................................................................... 7 IRAUDAMP6 OVERVIEW .............................................................................................................................. 12 FUNCTIONAL DESCRIPTIONS..................................................................................................................... 13 CLASS D OPERATION..................................................................................................................................... 13 POWER SUPPLIES.......................................................................................................................................... 13 BUS PUMPING ............................................................................................................................................... 14 HOUSE KEEPING POWER SUPPLY................................................................................................................... 14 INPUT............................................................................................................................................................ 15 OUTPUT........................................................................................................................................................ 15 LOAD IMPEDANCE.......................................................................................................................................... 15 GAIN SETTING / VOLUME CONTROL ................................................................................................................ 16 EFFICIENCY................................................................................................................................................... 16 OUTPUT FILTER DESIGN AND PREAMPLIFIER................................................................................................... 17 SELF-OSCILLATING PWM MODULATOR .......................................................................................................... 17 ADJUSTMENTS OF SELF-OSCILLATING FREQUENCY......................................................................................... 18 SWITCHES AND INDICATORS........................................................................................................................... 18 STARTUP AND SHUTDOWN ............................................................................................................................. 18 CLICK AND POP NOISE REDUCTION ............................................................................................................... 19 STARTUP AND SHUTDOWN SEQUENCING ........................................................................................................ 20 SELECTABLE DEAD-TIME................................................................................................................................ 23 LEVEL SHIFTERS ........................................................................................................................................... 23 PROTECTION SYSTEM OVERVIEW................................................................................................................... 24 Over-Current Protection (OCP)............................................................................................................... 24 Over-Voltage Protection (OVP)............................................................................................................... 26 Under-Voltage Protection (UVP)............................................................................................................. 26 Speaker DC-Voltage Protection (DCP)................................................................................................... 27 Offset Null (DC Offset) Adjustment ......................................................................................................... 27 Over-Temperature Protection (OTP) ...................................................................................................... 27 Thermal Considerations .......................................................................................................................... 27 Thermal Interface Materials Pressure Control ....................................................................................... 28 AMP6 Thermal pad pressure control calculation .................................................................................... 30 Short Circuit Protection Response.......................................................................................................... 31 IRAUDAMP6 FABRICATION MATERIALS................................................................................................... 37 IRAUDAMP6 PCB SPECIFICATIONS........................................................................................................... 42 REVISION CHANGES DESCRIPTIONS........................................................................................................ 46 www.irf.com Page 2 of 46 IRAUDAMP6 REV 1.0