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.