TPS5410 Startup Problem

Michael Wilson

Other Parts Discussed in Thread: TPS5410

I am using a TPS5410 to convert a 10 to 26 V input to a 4V output. It usually works fine, but refuses to power up other times. When it does not work the regulator looks like it keeps trying to start and can't. Here is my schematic.

Here is a screenshot of the waveform at TP9.

over 9 years ago

0 JohnTucker over 9 years ago

TI__Guru**** 191445 points

Under what conditions does it fail to start? It looks like it may be hiccup mode current limit.

0 Michael Wilson over 9 years ago in reply to JohnTucker

Prodigy 120 points

It fails as soon as power is applied to the board. If I touch around R50 and R51 it usually fixes itself and comes up. I have tried various capacitors around these resistors and it does not seem to help.

0 JohnTucker over 9 years ago in reply to Michael Wilson

TI__Guru**** 191445 points

touching the FB parts is generally not a good idea. Adding capacitors in parallel will alter the compensation. It is advised in some cases, but you most certainly cannot add them at random. What is Vin? can you include waveforms showing the PH node waveform as well as the inductor current? Also can I have the part number of (probably) C70?

0 Michael Wilson over 9 years ago in reply to JohnTucker

Prodigy 120 points

C70 is a Vishay TR3C476K016C0300.

Vin is either 12V or 24V depending on which power supply it used. All the waveforms I have posted have used a 12V input.

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TPS5410 Startup Problem