TPS2010, TPS2011, TPS2012, TPS2013

POWER-DISTRIBUTION

SLVS097A – DECEMBER 1994 – REVISED AUGUST 1995

15

POST OFFICE BOX 655303

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

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.

0

1

2

3

45

67

89

t – Time – ms

10

TPS2010

TPS2011

TPS2012

TPS2013

0

1

2

3

2.5

1.5

0.5