STSR30 Datasheet, PDF (1/10 Pages) STMicroelectronics – SYNCHRONOUS RECTIFIER SMART DRIVER FOR FLYBACK

STSR30
SYNCHRONOUS RECTIFIER
SMART DRIVER FOR FLYBACK
s SUPPLY VOLTAGE RANGE: 4V TO 5.5V
s TYPICAL PEAK OUTPUT CURRENT:
(SOURCE-SINK: 1.5A)
s OPERATING FREQUENCY: 20 TO 500 KHz
s INHIBIT BLANKING TIME: 700 ns
s AUTOMATIC TURN OFF FOR DUTY-CYCLE
LESS THAN 14%
s POSSIBILITY TO OPERATE IN
DISCONTINUOUS MODE
DESCRIPTION
STSR30 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withdrawn on the secondary side of the isolation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
BLOCK DIAGRAM
SO-8
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, detecting the voltage across the
Synchronous FET, allows to shut-off the drive
output during discontinuous mode condition. A
Disable pin allows turning off the device during
no-load condition reducing overall current
consumption.
January 2004
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