UC3901N.. (TEXAS INSTRUMENTS)

The UC3901N is an Isolated Feedback Generator designed to solve many of the problems associated with closing a feedback control loop across a voltage isolation boundary. As a stable and reliable alternative to an optical coupler. This device features an amplitude modulation system which allows a loop error signal to be coupled with a small RF transformer or capacitor. The programmable, high-frequency oscillator within the UC1901 series permits the use of smaller, less expensive transformers which can readily be built to meet the isolation requirements of today's line-operated power systems. As an alternative to RF operation, the external clock input to this device allows synchronization to a system clock or to the switching frequency of a SMPS. An additional feature is a status monitoring circuit which provides an active-low output when the sensed error voltage is within ±10% of the reference.