LTC1922-1 Synchronous Phase Modulated Full-Bridge Controller UFEATURESDESCRIPTIO ■ Adaptive DirectSenseTM Zero Voltage Switching The LTC®1922-1 phase shift PWM controller provides all ■ Integrated Synchronous Rectification Control for of the control and protection functions necessary to imple- Highest Efficiency ment a high performance, zero voltage switched, phase ■ Output Power Levels from 50W to Kilowatts shift, full-bridge power converter with synchronous recti- ■ Very Low Start-Up and Quiescent Currents fication. The part is ideal for developing isolated, low ■ Compatible with Voltage Mode and Current Mode voltage, high current outputs from a high voltage input Topologies source. The LTC1922-1 combines the benefits of the full- ■ Programmable Slope Compensation bridge topology with fixed frequency, zero voltage switch- ■ Undervoltage Lockout Circuitry with 4.2V Hysteresis ing operation (ZVS). Adaptive ZVS circuity controls the and Integrated 10.3V Shunt Regulator turn-on signals for each MOSFET independent of internal ■ Fixed Frequency Operation to 1MHz and external component tolerances for optimal perfor- ■ 50mA Outputs for Bridge Drive and Secondary Side mance. Synchronous Rectifiers The LTC1922-1 also provides secondary side synchro- ■ Soft-Start, Cycle-by-Cycle Current Limiting and nous rectifier control. The device uses peak current mode Hiccup Mode Short-Circuit Protection control with programmable slope comp and leading edge ■ 5V, 15mA Low Dropout Regulator blanking. ■ 20-Pin PDIP and SSOP Packages U The LTC1922-1 features extremely low operating and APPLICATIO S start-up currents to simplify off-line start-up and bias circuitry. The LTC1922-1 also includes a full range of ■ Telecommunications, Infrastructure Power Systems protection features and is available in 20-pin through hole ■ Distributed Power Architectures (N) and surface mount (G) packages. ■ Server Power Supplies , LTC and LT are registered trademarks of Linear Technology Corporation. ■ High Density Power Modules DirectSense is a trademark of Linear Technology Corporation. UTYPICAL APPLICATIO VIN 48V BIAS SUPPLY Efficiency 100 VOUT 3.3V 90 VIN = 48V VIN = 36V 80 EFFICIENCY (%) LTC1922-1 70 ISOLATED 60 FEEDBACK 0 10 20 30 40 LOAD CURRENT (A) 1922 • TA01b 1922 TA01a 1