Datasheet

ORing EXAMPLES
Input1
Input2
2200pF
Output
V
D
D
C GATE BYP
A
GND
2 20 0 pF
V
DD
C GATE BYP
A
GND
STAT
Input1
Input2
Output
10kW
TPS2410
TPS2411
www.ti.com .................................................................................................................................................. SLVS727C – NOVEMBER 2006 – REVISED JUNE 2009
Applications with the TPS2410/11 are not limited to ORIng of identical sections. The TPS2410/11 and external
MOSFET form a general purpose function block. Figure 19 shows a circuit with ORing between a discrete diode
and a TPS2410/MOSFET section. This circuit can be used to combine two different voltages in cases where the
output is reregulated, and the additional voltage drop in the Input 1 path is not a concern. An example is ORing
of an ac adapter on Input 1 with a lower voltage on Input 2 Figure 20 shows an improved efficiency version of the
first in which a P MOSFET replaces the simple diode. This circuit may not be useful in applications where Input 1
may be shorted because the P MOSFET is not managed, permitting reverse current flow. Input 2 should be the
lower of the two voltage rails. If Input 1 was the lower voltage rail and connected first, then Input 2 is connected,
there will be a momentary reverse current in the P MOSFET. The reverse current occurs because the STAT
signal will not go high until V
GATE
ramps above Input 2 (the higher voltage) by 0.4 V. The Input 1 to Input 2
difference voltage momentarily appears across the PMOS device which is turned on until STAT switches high,
causing a reverse current. The highest efficiency with the best fault tolerance is provided by two
TPS2410/MOSFET sections.
Figure 19. ORing Circuit Figure 20. P MOSFET Circuit
The TPS2410 may be a better choice in applications where inputs may be removed, causing an open-circuit
input. If the MOSFET was ON when the input is removed, V
AC
will be virtually zero. If the reverse turn-off
threshold is programmed negative, the TPS2410/11 will not pull GATE low. A system interruption could then be
created if a short is applied to the floating input. For example, if an ac adapter is first connected to the unit, and
then connected to the ac mains, the adapter's output capacitors will look like a momentary short to the unit. A
TPS2410 with RSET open will turn the MOSFET OFF when the input goes open circuit.
Copyright © 2006 – 2009, Texas Instruments Incorporated Submit Documentation Feedback 23
Product Folder Link(s): TPS2410 TPS2411