120 V/12 or 16 W Flyback Switching Regulators

The STR-A6131 and STR-A6132 are PRC topology (fixed off-time) regulators specifically designed to satisfy the requirements for increased integration and reliability in flyback converters. They incorporate a primary control and drive circuit with avalanche-rated power MOSFETs. The STR-A6132 features higher switching current and avalanche-energy ratings and lower on-resistance.

FEATURES ANDBENEFITS
■Rugged 500 V Avalanche-Rated MOSFET
   Simplified Surge Absorption
   No VDSSDerating Required
■Choice of rDS(on)(2.62 Ωor 3.95 Ωmaximum)
■Two Operational Modes by Automatic Switching:
   PRC Mode for Normal Operation
   Burst Mode for Stand-By Operation or Light Loads
■Built-In Leading Edge Blanking
■Low Start-Up Current Start-Up Circuit Disabled in Operation
■Low Operating Current (1.5 mA typ)
■Automatic Burst Stand-By (intermittent operation) Input Power <0.1 W at No Load
■Auto-Bias Function
   Stable Burst Operation Without Generating Interference
■Internal Off-Timer Circuit
■Built-In Constant-Voltage Drive
■Multiple Protections:
   Pulse-by-Pulse Overcurrent Protection
   Overload Protection with Auto Recovery
   Latching Overvoltage Protection
   Undervoltage Lockout with Hysteresis
   Latching Thermal Shutdown
■Molded Small-Size 8-Pin Package
   For Low-Height SMPS
   Polarized to Prevent Backwards Assembly