Datasheet

TPS62560, TPS62561
TPS62562
SLVS815C –JANUARY 2008–REVISED DECEMBER 2009 www.ti.com
ENABLE
The device is enabled by setting the EN terminal to high. During the start-up time t
Start Up
, the internal circuits are
settled and the soft-start circuit is activated. The EN input can be used to control power sequencing in a system
with various dc/dc converters. The EN terminal can be connected to the output of another converter, to drive the
EN terminal high to achieve a sequencing of the given supply rails. With EN = GND, the device enters shutdown
mode, in which all internal circuits are disabled. In fixed-output-voltage versions, the internal resistor divider
network is then disconnected from the FB terminal.
SOFT START
The TPS62560 has an internal soft-start circuit that controls the ramp-up of the output voltage. The output
voltage ramps up from 5% to 95% of its nominal value typically within 250 μs. This limits the inrush current into
the converter during ramp-up and prevents possible input voltage drops when a battery or high-impedance power
source is used. The soft-start circuit is enabled within the start-up time t
Start Up
.
SHORT-CIRCUIT PROTECTION
The high-side and low-side MOSFET switches are short-circuit protected with maximum switch current = I
LIMF
.
The current in the switches is monitored by current-limit comparators. Once the current in the high-side MOSFET
switch exceeds the threshold of its current-limit comparator, it turns off and the low-side MOSFET switch is
activated to ramp down the current in the inductor and high-side MOSFET switch. The high-side MOSFET switch
can only turn on again after the current in the low-side MOSFET switch has decreased below the threshold of its
current-limit comparator.
THERMAL SHUTDOWN
As soon as the junction temperature, T
J
, exceeds 140°C (typical), the device goes into thermal shutdown. In this
mode, the high-side and low-side MOSFETs are turned off. The device continues its operation when the junction
temperature falls below the thermal shutdown hysteresis.
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Product Folder Link(s): TPS62560 TPS62561 TPS62562