UC1845AY Datasheet PDF - Microsemi

●DESCRIPTION

●The UC184xA family of control ICs provides all the necessary features to implement off-line fixed-frequency, current-mode switching power supplies with a minimum of external components. The current mode architecture demonstrates improved load regulation, pulse-by-pulse current limiting and inherent protection of the power supply output switch. The IC includes: A bandgap reference trimmed to ±1% accuracy, an error amplifier, a current sense comparator with internal clamp to 1V, a high current totem pole output stage for fast switching of power MOSFET"s, and an externally programmable oscillator to set frequency and maximum duty cycle. The undervoltage lock-out is designed to operate with 250µA typ. start-up current, allowing an efficient bootstrap supply voltage design.

●KEY FEATURES

●■ LOW START-UP CURRENT. (0.5mA max.)

●■ TRIMMED OSCILLATOR DISCHARGE CURRENT. (See Product Highlight)

●■ OPTIMIZED FOR OFF-LINE AND DC-TO-DC CONVERTERS.

●■ AUTOMATIC FEED FORWARD COMPENSATION.

●■ PULSE-BY-PULSE CURRENT LIMITING.

●■ ENHANCED LOAD RESPONSE CHARACTERISTICS.

●■ UNDER-VOLTAGE LOCKOUT WITH HYSTERESIS.

●■ DOUBLE PULSE SUPPRESSION.

●■ HIGH-CURRENT TOTEM POLE OUTPUT.

●■ INTERNALLY TRIMMED BANDGAP REFERENCE.

●■ 500KHz OPERATION.

●■ LOW RO ERROR AMPLIFIER.

●APPLICATIONS

●■ ECONOMICAL OFF-LINE FLYBACK OR FORWARD CONVERTERS.

●■ DC-DC BUCK OR BOOST CONVERTERS.

●■ LOW COST DC MOTOR CONTROL.