The TPS23750 integrates the functionality of the TPS2375 with a primary side dc/dc PWM controller. The designer can create a front-end solution for PoE-PD applications with minimum external components. The TPS23770 is identical to the TPS23750 with the exception of the undervoltage lockout turn-on voltage, which is compatible with legacy systems.
The PoE front end has all the necessary IEEE 802.3af functions including detection, classification, undervoltage lockout and inrush control. The PoE input switch is integrated within the TPS23750.
The dc/dc controller section is designed to support flyback, forward, and nonsynchronous low-side switch buck topologies.
The external switching MOSFET and current sense resistor provide flexibility in topology, power level, and current limit. The full-featured dc/dc controller includes programmable soft start, hiccup type fault limiting, 50% maximum duty cycle, programmable constant switching frequency, and a true voltage-output error amplifier. Additional protection features provide for robust designs.