UC2855AN

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 MOSFETs, 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.