TIDA-01494: Ripple Noise, Power limitation.

Seongwoong kim

Intellectual 420 points

Part Number: TIDA-01494

Hi Ti,

We are developing the custom smps board based on the (TIDA-01494 + TIDA0153).

We have some issues..

First Case

ripple noise : max 3 Volt. Can you give us some advice..?

Second Case,

the power is limited to the 500W. if the current 18A / 27V is over loaded, the voltage is down to the 24Volt and it's out of order..

over 3 years ago

0 Desheng, Guo over 3 years ago

TI__Expert 5920 points

Hi, Kim

1st case:

please limit your probe bandwitdh to 20MHz, and use the minmized probe loop, to do the test.

If this spike still exsit, please check your feedback loop, to see what happens in mistake.

2nd case:

I guess the feedback is limited by output current, please enlarge the current limitation in the feedback circuits.

0 Seongwoong kim over 3 years ago in reply to Desheng, Guo

Intellectual 420 points

Hi,

1st case:

the below image is limited to the 20MHz..

let me know the point in detail about the feedback loop.

Thanks

Regards

Nick.

0 Desheng, Guo over 3 years ago in reply to Seongwoong kim

TI__Expert 5920 points

Hi,

please refere to the following for your ripple test method.

And if you still see the voltage spike, please extend the waveform for the detail, let's see its osc frequency.

0 Seongwoong kim over 3 years ago in reply to Desheng, Guo

Intellectual 420 points

Hi,

The below waveform is measured

The oscillopscope probe is very close to the power and ground..

How about your opinion?

Regards,

Nick.

0 Desheng, Guo over 3 years ago in reply to Seongwoong kim

TI__Expert 5920 points

Hi,

Your waveform show an high frequency oscillation, this is large possible introduced by switching of MOSFET.

Please check all the MOSFET Vds voltage, and using snubber absorb it.

And, there is 100kHz swiching frequency ripple. It need you to reduce the ESR of filter cap, you may use more ceramic capacitors to suppress it.

0 Seongwoong kim over 3 years ago in reply to Desheng, Guo

Intellectual 420 points

Hi,

I think the issue is coming from the transformer..

we made it by ourselves.

Would you let us know the transformer spec of TIDA-01494 ?

core spec. cable. etc..

Thanks

Regards,

Nick.

0 Desheng, Guo over 3 years ago in reply to Seongwoong kim

TI__Expert 5920 points

Hi, Kim

This is what I have from our designer. please refer.

750343657,Rev02 datasheet, UCC256301,24V20A,ETD44,TIDA-01494.pdf

0 Seongwoong kim over 3 years ago in reply to Desheng, Guo

Intellectual 420 points

Hi ,

I've contacted the wurth and the transformer : delivery time is long. (12~14 weeks)

so we want to make it..

Let us know the core spec and how to turn the line etc.

Thanks.

Regards,

Nick.

0 Desheng, Guo over 3 years ago in reply to Seongwoong kim

TI__Expert 5920 points

Hi, Nick

The infomation you asked is kept by Wurth, we do not have this infomation, because the designer do not leave this to us.

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TIDA-01494: Ripple Noise, Power limitation.