Beschreibung
Power over Ethernet (PoE) is a technology that allows network cables to deliver power to a powered device (PD) through power-sourcing equipment (PSE) or midspan, and has many advantages over traditional methods of delivering power. PoE allows power and data to be combined, removing the need for altering the AC mains infrastructure and can be installed by non-electricians. PoE is an intelligent system designed with protection at the forefront, preventing overload, underpowering, and installation errors, while allowing simple scalability and reliability.The MAX17690 implements an innovative algorithm to accurately determine the output voltage by sensing the reflected voltage across the primary winding during the flyback time interval. By sampling and regulating this reflected voltage when the secondary current is close to zero, the effects of secondary-side DC losses in the transformer winding, the PCB tracks, and the rectifying diode on output voltage regulation can be minimized. The MAX17690 also compensates for the negative temperature coefficient of the rectifying diode.
Eigenschaften
IEEE 802.3af/at ComplianceThermally Enhanced, 3mm × 3mm, 10-Pin TDFN Package (MAX5969B)30V to 60V Input Voltage RangeProgrammable Switching Frequency from 50kHz to 250kHzProgrammable Input Enable/UVLO FeatureProgrammable Input Overvoltage ProtectionAdjustable Soft-Start2A/4A Peak Source/Sink Gate Drive CapabilityHiccup Mode Short-Circuit ProtectionFast Cycle-by-Cycle Peak Current LimitThermal Shutdown ProtectionSpace-Saving, 16-Pin, 3mm × 3mm TQFN Package-40°C to +125°C Operating Temperature Range