STSR3

STSR3 SYNCHRONOUS RECTIFIERS SMART DRIVER FOR FLYBACK s s s s s s SUPPLY VOLTAGE RANGE: 4V TO 5.5V TYPICAL PEAK OUTPUT CURRENT: (SOURCE 2A, SINK 3.5A) OPERATING FREQUENCY: 30 TO 750 KHz SMART TURN-OFF ANTICIPATION TIMING AUTOMATIC TURN OFF FOR DUTY CYCLE LESS THAN 14% POSSIBILITY TO OPERATE IN DISCONTINUOUS MODE SO-8 www.DataSheet4U.com DESCRIPTION STSR3 Smart Driver IC provides a high current outputs to properly drive secondary Power Mosfets used as Synchronous Rectifier in low output voltage, high efficiency Flyback Converters. From a synchronizing clock input, withdrawn on the secondary side of the isolation transformer, the IC generates a driving signal with set dead times with respect to the primary side PWM signal. The IC operation prevents secondary side shoot-through conditions at turn-on of the primary switch providing anticipation in turn-off the output. This smart function is implemented by a fast cycle-after-cycle logic control mechanism, based on a high frequency oscillator synchronized by the clock signal. This anticipation is externally set through external component. A special Inhibit function allows to shut-off the drive output. This feature makes discontinuous conduction mode possible and avoids reverse conduction of the synchronous rectifier. SCHEMATIC DIAGRAM Vcc 2 + BIAS UVLO 5.7V CK 4 PEAK DETECTOR ANTICIPATION SET 3 SETANT + HIGH FREQUENCY OSCILLATOR DIGITAL CONTROL OUTPUT BUFFER + 7 OUTGATE INHIBIT 5 + 25mV 1 N/C 6 8 SGLGND PW...