LM3401 shutdown current

Fredrik K

Other Parts Discussed in Thread: LM3401, LM3405, TPS92512

Hi,

What is the shutdown current of the LM3401? From the datasheet IQ is specified at ~1 mA for non-switching operation. Does this mean that the current consumption when DIM is held low is 1 mA?

Can I reduce this by removing power from Vin, or would this pull HG to ground and thus turn the transistor on?

I guess the last option would be to add another PMOS cutting off power to the entire driver, or do you have any better recommendations? I am targeting shut-down current in the uA range.

Thanks!
Fredrik

over 9 years ago

0 Clinton Jensen over 9 years ago

TI__Mastermind 25500 points

The LM3401 does not have a low power shutdown feature, so yes it will draw 1mA. An input disconnect would do the trick, but if your current is low enough you could consider other parts in the LM340x family. Some of them had a low power shutdown feature.

0 Fredrik K over 9 years ago in reply to Clinton Jensen

TI__Guru** 106705 points

Hi Clinton,

Thank you for your reply. I have been using the LM3405 in a couple of designs, but for this I would need >2.5 A LED current.

If I remove power from Vin only, but still have power on the PFET source, will the transistor be turned off?

I am also considering the TPS92512. Can I use the UVLO pin as a logic enable/disable?

Best regards,
Fredrik

0 Clinton Jensen over 9 years ago in reply to Fredrik K

TI__Mastermind 25500 points

I'm not sure about the LM3401 gate drive, but I'm guessing from the block diagram (I haven't used this part much) that the gate could easily find itself below the Vth and allow the PFET to turn on. You would probably need to disconnect both.
The TPS92512 does have low power shutdown via the UVLO pin and you could use a logic level signal to drive it.

0 Fredrik K over 9 years ago in reply to Clinton Jensen

TI__Guru** 106705 points

Ok. Thanks!

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LM3401 shutdown current