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ENABLE

SOFT START

SHORT-CIRCUIT PROTECTION

THERMAL SHUTDOWN

TPS62290, TPS62291, TPS62293

SLVS764C – JUNE 2007 – REVISED MARCH 2008

Afterwards, the device activates the soft start circuit. The EN input can be used to control power sequencing in a

system with various dc/dc converters. The EN pin can be connected to the output of another converter, to drive

the EN pin high and getting a sequencing of supply rails. With EN = GND, the device enters shutdown mode. In

this mode, all circuits are disabled. In fixed output voltage versions, the internal resistor divider network is

disconnected from FB pin.

The TPS6229x 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 within typical 250

µs. This limits the inrush current in the

converter during ramp up and prevents possible input voltage drops when a battery or high impedance power

The current in the switches is monitored by current limit comparators. Once the current in the High Side

MOSFET switch exceeds the threshold of it's 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, once the current in the Low Side MOSFET switch has decreased below

the threshold of its current limit comparator.

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.

Copyright © 2007–2008, Texas Instruments Incorporated

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Product Folder Link(s): TPS62290 TPS62291 TPS62293