Datasheet

TPS2010, TPS2011, TPS2012, TPS2013
POWER-DISTRIBUTION
SLVS097A – DECEMBER 1994 – REVISED AUGUST 1995
15
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
APPLICATION INFORMATION
overcurrent
A sense FET is employed to check for overcurrent conditions. Unlike sense resistors and polyfuses, sense FETs
do not increase series resistance to the current path. When an overcurrent condition is detected, the device
maintains a constant output current and reduces the output voltage accordingly. Shutdown only occurs if the
fault is present long enough to activate thermal limiting.
Three possible overload conditions can occur. In the first condition, the output has been shorted before the
device is enabled or before V
I(IN)
has been applied (see Figure 30). The TPS201x senses the short and
immediately switches into a constant-current output.
Under the second condition, the short occurs while the device is enabled. At the instant the short occurs, very
high currents flow for a short time before the current-limit circuit can react (see Figures 5, 6, 7, and 8). After the
current-limit circuit has tripped, the device limits normally.
Under the third condition, the load has been gradually increased beyond the recommended operating current.
The current is permitted to rise until the current-limit threshold is reached (see Figures 9, 10, 11, and 12). The
TPS201x family is capable of delivering currents up to the current-limit threshold without damage. Once the
threshold has been reached, the device switches into its constant-current mode.
Figure 30. Turned-On (Enabled) Into Short Circuit, V
I(IN)
= 5.5 V
0123456789
t – Time – ms
10
TPS2010
TPS2011
TPS2012
TPS2013
0
1
2
3
2.5
1.5
0.5
– Output Current – A
I
O