Datasheet
1.016
ILIM
OSmin
25230V
OSmin
R k
1
1.016
ILIM
OSmin
ILIM
I (mA) = 1000mA
I (mA) =
25230V
R (k ) =
I mA
R (k ) = 24k
W
W
W W
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ILIM
OSmax
0.94
ILIM
OSmax
0.94
OSmax
R (k ) = 23.7k
22980V
I (mA) =
R k
22980V
I (mA) =
23.7 k
I (mA) = 1172.4mA
W W
W
W
0.94
ILIM
OSmax
22980V
OSmax
R k
1
0.94
ILIM
OSmax
ILIM
I (mA) = 500mA
I (mA) =
22980V
R (k ) =
I mA
R (k ) = 58.7k
W
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ILIM
OSmin
1.016
ILIM
OSmin
1.016
OSmin
R (k ) = 59k
25230V
I (mA) =
R k
25230V
I (mA) =
59 k
I (mA) = 400.6mA
W W
W
W
TPS2552, TPS2553
TPS2552-1, TPS2553-1
SLVS841E –NOVEMBER 2008– REVISED FEBRUARY 2012
www.ti.com
APPLICATION 1: DESIGNING ABOVE A MINIMUM CURRENT LIMIT
Some applications require that current limiting cannot occur below a certain threshold. For this example, assume
that 1 A must be delivered to the load so that the minimum desired current-limit threshold is 1000 mA. Use the
I
OS
equations and Figure 24 to select R
ILIM
.
(2)
Select the closest 1% resistor less than the calculated value: R
ILIM
= 23.7 kΩ. This sets the minimum current-limit
threshold at 1 A . Use the I
OS
equations, Figure 24, and the previously calculated value for R
ILIM
to calculate the
maximum resulting current-limit threshold.
(3)
The resulting maximum current-limit threshold is 1172.4 mA with a 23.7 kΩ resistor.
APPLICATION 2: DESIGNING BELOW A MAXIMUM CURRENT LIMIT
Some applications require that current limiting must occur below a certain threshold. For this example, assume
that the desired upper current-limit threshold must be below 500 mA to protect an up-stream power supply. Use
the I
OS
equations and Figure 24 to select R
ILIM
.
(4)
Select the closest 1% resistor greater than the calculated value: R
ILIM
= 59 kΩ. This sets the maximum
current-limit threshold at 500 mA . Use the I
OS
equations, Figure 24, and the previously calculated value for R
ILIM
to calculate the minimum resulting current-limit threshold.
(5)
The resulting minimum current-limit threshold is 400.6 mA with a 59 kΩ resistor.
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