Datasheet

EN
SS/TR
V
SENSE
VOUT
TPS54260
SLVSA86A –MARCH 2010–REVISED DECEMBER 2010 www.ti.com
DETAILED DESCRIPTION (continued)
Figure 29. Operation of SS/TR Pin when Starting
Overload Recovery Circuit
The TPS54260 has an overload recovery (OLR) circuit. The OLR circuit will slow start the output from the
overload voltage to the nominal regulation voltage once the fault condition is removed. The OLR circuit will
discharge the SS/TR pin to a voltage slightly greater than the VSENSE pin voltage using an internal pull down of
382mA when the error amplifier is changed to a high voltage from a fault condition. When the fault condition is
removed, the output will slow start from the fault voltage to nominal output voltage.
Sequencing
Many of the common power supply sequencing methods can be implemented using the SS/TR, EN and PWRGD
pins. The sequential method can be implemented using an open drain output of a power on reset pin of another
device. The sequential method is illustrated in Figure 30 using two TPS54260 devices. The power good is
coupled to the EN pin on the TPS54260 which will enable the second power supply once the primary supply
reaches regulation. If needed, a 1nF ceramic capacitor on the EN pin of the second power supply will provide a
1ms start up delay. Figure 31 shows the results of Figure 30.
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