40W Single Port MAX5971A Current Sensing

Abstract: Many PoE power sourcing equipment (PSE) single port applications require real time knowledge of the powered device (PD) current used after startup. This application note details a method to obtain real time current monitoring and reporting of the actual current sent to the PD. It uses a MAX4080 high-side, current-sense amplifier and a current sense resistor on the PSE high-side power path.