TPS65130 Vout Malfunction

T Kishi

Genius 4425 points

My customer has question.Please tell me.

As a phenomenon, the Vout(VPOS) at no load is swaying between 16V and 15V.

Please see the attached file.

In addition, in the circuit diagram of attachment has COUT is 4.7 × 4 with.

If you change to COUT = 4.7uF × 1, this phenomenon is improved.

However, COUT in the data sheet recommends a 4.7uF × 4.

Is there is something possible causes?
I want you to tell us as soon as possible.

Waveform_Circuit.pdf

Regard

T Kishi

over 10 years ago

0 Ilona over 10 years ago

TI__Expert 8010 points

Hi T Kishi,

In your schematic the capacitors on CP/CN are way too big! These are the compensation capacitors of the feedforward system, they must be in the range of nF for fast regulation. Can you change CP=10nF and CN=4.7nF and give feedback whether there changed something on the output?

Thank you,
Best Regards,
Ilona

0 T Kishi over 10 years ago in reply to Ilona

Genius 4425 points

Hi Ilona

Sorry,Constant was incorrect.

Please check you again because I had to modify the circuit.

Regard

T Kishi

1256.Waveform_Circuit.pdf

0 Ilona over 10 years ago in reply to T Kishi

TI__Expert 8010 points

Hi T Kishi,

Yes now it looks good. Does it work now? Or does it show the same failing behavior?

Regards,

Ilona

0 T Kishi over 10 years ago in reply to Ilona

Genius 4425 points

Hi Ilona

Yes.The first symptoms that are described in is happening.
In addition, the phenomenon in 20 vehicles trial, is happening on only one.
Will there also Device of trouble?

Regard
TKishi

Power management

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TPS65130 Vout Malfunction