Producer:  Tetax Instrument (TI)

Features

 • Optimized for Off-Line and DC-to-DC Converters
 • Low Start-Up Current (< 1 mA)
 • Automatic Feedforward Compensation
 • Pulse-by-Pulse Current Limiting
 • Enhanced Load-Response Characteristics
 • Undervoltage Lockout With Hysteresis
 • Double-Pulse Suppression
 • High-Current Totem-Pole Output
 • Internally Trimmed Bandgap Reference
 • Up to 500-kHz Operation
 • Error Amplifier With Low Output Resistance

Applications
 • Switching Regulators of Any Polarity
 • Transformer-Coupled DC-DC Converters

Description

 • The UCx84x series of control integrated circuits provide the features that are necessary to implement off-line or DC-to-DC fixed-frequency current-mode control schemes, with a minimum number of external components. The internally implemented circuits
include an undervoltage lockout (UVLO), featuring a start-up current of less than 1 mA, and a precision reference trimmed for accuracy at the error amplifier input. Other internal circuits include logic to ensure latched operation, a pulse-width modulation (PWM) comparator that also provides current-limit control, and a totem-pole output stage that is designed to source or sink high-peak current. The output stage, suitable for driving N-channel MOSFETs, is low when it is in the off state.