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