LM5069: During short circuit condition

Ramachandran Sivanehru

Intellectual 265 points

Part Number: LM5069

Hi,

What limits the output voltage during the the short circuit condition.

Its goes into a restart mode if the short circuit is permanent, what determines when to turn off after every restart.

The current limit was set to 18A, the voltage rail is 50V, the short circuit was simulated using 2R2 power resistor.

The output voltage reaches to ~4V before the Hot swap disabled it. the current through the resistor is around ~ 2A during every restart.

Thanks

Siva

over 4 years ago

0 Rakesh over 4 years ago

TI__Guru** 105361 points

Hi Siva,

The short circuit current will be limited to lowest of Power limit set current (PLIM/Vds) and the current limit 18A, which ever is lower. The output voltage will be 2R2 multiplied by that current.

Time to restart is determined by the cap on the TIMER pin.

Best Regards, Rakesh

0 Ramachandran Sivanehru over 4 years ago in reply to Rakesh

Intellectual 265 points

Thanks Rakesh,

its make sense, the power limit is 88W and the Vds is 50V, which gives you 1.76A, the voltage drop across the resistor is ~4V.

Regards

Siva

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LM5069: During short circuit condition