Datasheet

0 240
R
SP
- SP Resistor - kW
0
100
150
400
120
300
D
SP
- SP Dead Time - ns
SP DEAD TIME
vs
SP RESISTOR
250
200
50
10080604020 140 160 180 200 220
350
UCC28250
www.ti.com SLUSA29C –APRIL 2010– REVISED JULY 2011
SP (Synchronous Rectifier Turn-Off to Primary Output Turn-On Dead Time Programming) (13/19)
The dead time T
D(sp)
between synchronous rectifier turn-off to primary output turn-on is programmed by an
external resistor, R
SP
, connected between the SP pin and ground. The value of R
SP
can be determined by
Figure 9. Zero dead time can be achieved by tying the SP pin to VREF. The falling edge of synchronous rectifier
SRA/SRB is aligned with the raising edge of the primary output OUTA/OUTB.
NOTE
The minimum value for R
PS
/R
SP
is 5 kΩ and the maximum value is 250 kΩ.
Figure 9. Dead Time T
D(sp)
vs. External Resistor R
SP
at SP Pin
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