LM2611: Inrush current limitation

M.A.M

Part Number: LM2611

Hi,

My customer is evaluating the LM2611 and wishes to reduce the inrush current at startup.
He is using the TI Dev board, +5V input and -5V output and a 390ohm load resistor.

With 300mA limit enabled on the PSU it does not start correctly. In E2E I found another thread that even 500mA was not enough, but raising the current limit to 1A made it boot correctly.

Please help us understand
1) what design tricks we can use to make it boot with less than 500mA of current in above use-case, and
2) what is the reason for the device to behave like s short circuit if the needed inrush current cannot be supplied?

Thanks in advance.

/M.A.M

over 4 years ago

0 Youhao Xi over 4 years ago

TI__Guru 74420 points

Hi M.A.M,

Can you insert a PTC Thermistor between the PSU and the converter input port to limit the inrush current? Another option is, try to delay /SHDN by inserting an R and C delay circuit such that the PSU voltage is established before the LM2611 operates.

Thanks,

Youhao Xi, Applications Engineering

0 Youhao Xi over 4 years ago in reply to Youhao Xi

TI__Guru 74420 points

May I assume this issue is resolved? I am closing it here but you are welcome to reopen it by adding a new post.

Thanks,

Youhao

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LM2611: Inrush current limitation