TPS62590

www.ti.com

SLVS897B

– JANUARY 2009 – REVISED APRIL 2011

ENABLE

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.

SOFT START

The TPS62590 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

SHORT-CIRCUIT PROTECTION

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, once the current in the Low-Side MOSFET switch has decreased below

the threshold of its current limit comparator.

THERMAL SHUTDOWN

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

© 2009–2011, Texas Instruments Incorporated

13