Datasheet

INPUT ORing AND STAT
OV
GND
STAT
PullLow
toReset
LogicRail
TPS2410
TPS2411
www.ti.com .................................................................................................................................................. SLVS727C – NOVEMBER 2006 – REVISED JUNE 2009
STAT provides information regarding the state of the MOSFET gate drive. STAT is pulled to V
DD
, through a
46-k Ω internal pullup, if GATE is being driven high and V
(GATE)
exceeds V
(A)
plus 0.4 V. The STAT pin may be
directly connected to low-voltage logic by using the logic gate's input ESD clamp to control the voltage or by
using a much lower pullup resistor (e.g., 5 k Ω ) to the logic supply voltage. STAT must be allowed to rise above
V
DD
/2 to avoid effecting the reverse turn-off threshold.
Interconnecting STAT pins can be used to reduce the occurence of both MOSFETs turning off in topologies such
as Figure 13 that normally have both MOSFETs ON. This might occur when there is a noise transient on both
buses due to fans cycling on and off, or an ac mains disturbance. If both MOSFETs are ON, and then an ORing
circuit turns OFF, the second ORing circuit's fast turnoff threshold is shifted negative by 157 mV from the RSET
programmed value because STAT is pulled low. This reduces the probability that it too will turn off as the arrival
of the transient, and speed of both circuits, is unlikely to be matched. Maintaining at least one device ON avoids
both a bus transient due to the current interruption, and momentary downstream hotswap overload when the
ORing recovers. The function of STAT is not limited to the topology of Figure 13 and may be used to dynamically
shift the fast turnoff threshold. The internal circuit shown in the FUNCTIONAL BLOCK DIAGRAM will assist in
designing these applications.
Figure 17 shows how STAT and OV can be used to latch the TPS2410 off. This is useful when a system
operation benefits from preventing a failed power module from repeatedly disturbing the bus, and may be used in
conjunction with back-to-back MOSFETs. The OV pin must be help low until V
(GATE)
is 0.4 V above V
(A)
in order
to accomplish a reset.
Figure 17. Use of STAT and OV to Latch TPS2411 OFF
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