Datasheet

I
SEC
V
GATE
V
THON
t
rGATE
t
DON
4 V
1 V
V
THOFF
t
fGATE
t
DOFF
4 V
1 V
V
DS
V
THARM
(V)
(t)
(A),
V10095
UCC24610
www.ti.com
SLUSA87B AUGUST 2010REVISED SEPTEMBER 2010
The UCC24610 SR controller determines the conduction time of the SR-MOSFET by comparing the MOSFET’s
drain-to-source voltage against a turn-on threshold and a turn-off threshold. The GATE output is driven High
when V
DS
of the MOSFET exceeds V
TH(on)
and is driven Low when V
DS
decreases below V
TH(off)
as illustrated in
Figure 18.
Figure 18. GATE Output With Respect to V
DS
Note that because of finite propagation and rise times, the body diode of the SR-MOSFET may conduct briefly
after V
TH(on)
has been exceeded. Also, the body-diode conducts the residual secondary current after V
TH(off)
has
been crossed. A waveform similar to that of V
DS
depicted in Figure 18 can be observed during SR operation in a
simple flyback circuit.
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