TPS62240_13 Datasheet, PDF (15/29 Pages) Texas Instruments – 2.25 MHz 300 mA Step Down Converter in 2x2SON/TSOT23 Package

TPS62240, TPS62242, TPS62243
www.ti.com
SLVS762B – JUNE 2007 – REVISED SEPTEMBER 2007
SOFT START
The TPS62240 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 250µs. This limits the inrush current in 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 equal to
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 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.
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.
Copyright © 2007, Texas Instruments Incorporated
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Product Folder Link(s): TPS62240 TPS62242 TPS62243