TPS2343

SLUS644B − FEBRUARY 2005 − MAY 2005

23

www.ti.com

APPLICATION INFORMATION

Overload trip point with MISET = 6.04 k

W.

R

V

TRIP(nom)

I

TRIP(nom)

+ 23.5 mV

4.0 A

+ 0.00598W

Choose 0.006

Ω

I

20 mV

0.00612

W +

3.27 A

MIN

I

27 mV

0.00588

W +

4.594 A

MIN

Thermal Shutdown

Under normal operating consitions, the power dissipation in the TS2343 is low enough that the junction

PCI specifications (but remains under the TPS2343 overcurrent threshold) power dissipation can be higher. To

prevent any damage from an out-of-specification load or severe rise in ambient temperature, the TPS2343

contains two independent thermal shutdown circuits, one for each main supply slot. VAUX is not affected by the

thermal shutdown.

The highest power dissipation in the TPS2343 is from the 12-V power FET so that TPS2343 temperature sense

elements are integrated closely with these FETs. These sensors indicate when the temperature at these

transistors exceeds approximately 150

°C, due either to average device power dissipation, 12-V power FET

power dissipation, or a combination of both.

When excessive junction temperature is detected in one slot, that slot’s fault latch is set and remains set until

the junction temperature drops by approximately 10

°C and the slot is then restarted. The other slot is not

affected by this event.