4-45 V Input Current Mode Isolated Flyback PWM Controller

The NCP12711 is a fixed−frequency peak−current−mode PWM controller containing all of the features necessary for implementing single−ended power converter topologies. The device operates from 4 V to 45 V without auxiliary winding and within its thermal capabilities. The controller contains a programmable oscillator capable of operating from 100 kHz to 1 MHz and integrates slope compensation to prevent subharmonic oscillations. The controller includes a programmable soft−start, input voltage UVLO protection, and an over−power protection (OPP) circuit which limits the total power capability of the circuit as the input voltage increases. The UVLO pin also features a shutdown comparator which allows for an external signal to disable switching and brings the controller into a low quiescent state. An onboard op−amp allows the implementation of primary−side regulated converters or non−isolated dc−dc converters.