Dual SmartRectifier TM – DirectFET Chipset Solution Overcomes Package Induced Sensing Limitations Allowing High Performance Synchronous Output Rectification in LCD TV Power Supplies

摘要

We discuss the effect of stray inductance (package and layout induced), both, major limitations observed in implementing high performance synchronous output rectification in DC-DC resonant converters with voltage sensing control techniques and propose an innovative chipset that resolves these issues. The proposed solution also allows synchronous rectification to be implemented on multiple output rails by simply using one controller IC and enables a no-heatsink implementation in low and medium power LCD TV output rectifier stages. This solution is implemented in a 230W commercial LCD TV power supply where Schottky diodes were initially used. Finally, system performance improvements with this solution are discussed towards the end.