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.