TLV61046A: Startup Issue

Mark Ackerson

Part Number: TLV61046A

Customer is having issues with TLV61046A. Circuit is right out of the data sheet with FB connected to VIN. I'm assuming this could be related to the startup limitations detailed in the How to Improve the Loading Capability of TLV61046A During Start-up app note. Load is 12V at 10 mA. I'm thinking startup transient current could the the issue. I've asked the customer to investigate.

What do you think?

Regards,
Mark

over 5 years ago

0 Youhao Xi over 5 years ago

TI__Guru* 78190 points

Hi Mark,

Thank you for posting. I am notifying our expert who is currently on holidays and will be back next week.

Thanks,

Youhao Xi, Applications Engineering

0 Mark Ackerson over 5 years ago in reply to Youhao Xi

TI__Genius 10190 points

Hi Youhao,

Thanks for the update. As it turns out the customer might have been blowing up the parts through a sneak circuit.

One question they did have is what would be the impact of using a 100uh inductor? I looked at the inductor current and it spikes to 150 or 100ma with the 4.7uh. I have a low current (30ma application).

My response was the TLV61046A is designed to work with inductor values between 2.2 µH and 22 µH. So I would be potentially concerned with stability.

I tried simulating the 100uH inductor in Webench, but I’m not sure the model is valid since it complained about me overriding the limits.

What do you think?

Regards,
Mark

0 Youhao Xi over 5 years ago in reply to Mark Ackerson

TI__Guru* 78190 points

Hi Mark,

Please wait a couple of days for Jasper to answer you for sure.

Thanks,

Youhao

0 Jasper Li over 5 years ago in reply to Mark Ackerson

TI__Mastermind 46905 points

Hi Mark,

your are correct. please reduce the inductor to 10uH firstly to check if the issue could be solved

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TLV61046A: Startup Issue