6533b828fe1ef96bd1288c20

RESEARCH PRODUCT

A lossless current sensing technique for flyback converters

Giuseppe CapponiFilippo MarinoA. De LumeValeria Boscaino

subject

business.industryFlyback converterComputer scienceFlyback transformerElectrical engineeringSense (electronics)ConvertersCurrent transformerOvercurrentlaw.inventionCapacitorlawMOSFETElectronic engineeringResistorPower MOSFETbusinessRC circuitPulse-width modulationVoltage

description

Regardless of the feedback control, almost all converters require input or output current sense for overcurrent protection. If a current mode control is implemented, high accuracy is also required. The optimal current sensing method shows the highest accuracy and the lowest power dissipation. In this paper, a lossless and accurate current sensing technique for Flyback converters is proposed. An RC network is parallel connected with the primary MOSFET and the voltage signal across the sense capacitor accurately reproduces the magnetizing current waveform. The RC technique benefits from all the advantages of the most common current sensing techniques currently applied to Flyback converters, as resistive or current transformer methods, cutting-off their main drawbacks. The sense network affects neither the cost nor the efficiency of the overall power supply system. The proposed technique can be efficiently applied to all PWM converters, both in continuous and discontinuous conduction mode and it is suitable for current mode control implementation. A current mode PWM Flyback converter has been designed to test the RC sense efficiency and accuracy and simulation results are shown.

yearjournalcountryeditionlanguage
2009-11-012009 35th Annual Conference of IEEE Industrial Electronics
https://doi.org/10.1109/iecon.2009.5414808