The UC2901 is 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, UC2901 features an amplitude modulation system that allows a loop error signal to be coupled with a small RF transformer or capacitor.
The programmable, high-frequency oscillator within the UC2901 permits the use of smaller, less-expensive transformers, which can readily be built to meet the isolation requirements of todays line-operated power systems. As an alternative to RF operation, the external clock input to these devices allows synchronization to a system clock or to the switching frequency of an SMPS.
An additional feature is a status monitoring circuit that provides an active low output when the sensed error voltage is within ±10% of the reference. The DRIVERA output, DRIVERB output, and STATUS output are disabled until the input supply has reached a sufficient level to allow proper operation of the device.
Because these devices also can be used as a DC driver for optical couplers, the benefits of 4.5 V to 40 V supply operation, a 1% accurate reference, and a high-gain general-purpose amplifier offer advantages, even though an AC system may not be desired.
(1) Component qualification in accordance with JEDEC and industry standards to ensure reliable operation over an extended temperature range. This includes, but is not limited to, Highly Accelerated Stress Test (HAST) or biased 85/85, temperature cycle, autoclave or unbiased HAST, electromigration, bond intermetallic life, and mold compound life. Such qualification testing should not be viewed as justifying use of this component beyond specified performance and environmental limits.