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Texas Instruments LM5181/LM5181-Q1 PSR Flyback Converters

Texas Instruments LM5181/LM5181-Q1 Primary-Side Regulated (PSR) Flyback Converters come with high efficiency over a wide input voltage range of 4.5V to 65V. The isolated output voltage is sampled from the primary-side flyback voltage, eliminating the need for an optocoupler, voltage reference, or third winding from the transformer for output voltage regulation. The high level of integration results in a simple, reliable, and high-density design with only one component crossing the isolation barrier. Boundary conduction mode (BCM) switching enables a compact magnetic solution and better than ±1.5% load and line regulation performance. An integrated 100V power MOSFET provides output power up to 4W with enhanced headroom for line transients. The Texas Instruments LM5181/LM5181-Q1 flyback converters are available in an 8-pin, 4mm × 4mm, thermally-enhanced WSON package with a 0.8mm pin pitch. The LM5181-Q1 devices are AEC-Q100 qualified for automotive applications.

Features

  • Designed for reliable and rugged applications
    • Wide input voltage range of 4.5V to 65V with operation down to 3.5V after start-up
    • Robust solution with only one component crossing the isolation barrier
    • ±1.5% total output regulation accuracy
    • Optional VOUT temperature compensation
    • 6ms internal or programmable soft-start
    • Input UVLO and thermal shutdown protection
    • Hiccup-mode overcurrent fault protection
    • –40°C to +150°C junction temperature range
  • Integration reduces solution size and cost
    • Integrated 100V, 0.4Ω power MOSFET
    • No optocoupler or transformer auxiliary winding required for VOUT regulation
    • Internal loop compensation
  • High-efficiency PSR flyback operation
    • Quasi-resonant MOSFET turn-off in BCM
    • Low input quiescent current
    • External bias option for improved efficiency
    • Single- and multi-output implementations
  • Ultra-low conducted and radiated EMI signatures
    • Soft switching avoids diode reverse recovery
    • Optimized for CISPR 32 EMI requirements

Applications

  • Isolated field transmitters and field actuators
  • Multi-output rails for analog input modules
  • Motor drives
  • IGBT and SiC gate drive supplies
  • Building automation HVAC systems
  • Isolated bias supplies

Functional Block Diagram

Block Diagram - Texas Instruments LM5181/LM5181-Q1 PSR Flyback Converters

Texas Instruments LM5181/LM5181-Q1 PSR Flyback Converters