TPS61287: Comp setting and schematic review

Hi Jeff,

Thank you for reaching out.

The calculation tool is not released yet.

1. Please add some ceramic capacitors to the output side.

2. the compensation parameters can be choose as: Rcomp=40k,Ccomp=47nF,and Cp=100pF;

Could you share the EE of this case?

Best Regards,

Fergus

Hi Fergus,

We found if we provide 20V but IC is damaged(Vin short to Vout).

Would you please help us review the board file?

Thanks!

27-0520-000-4CW Riobuds Anyuse cable X1-0.pcb

Jeff

Hi Jeff,

Sorry the attached file can not be open with Altium or Candence.

Could you double check the document?

Best Regards,

Fergus

Hi Fergus,

FYI, it is 2 layer board.

Hi Jeff,

Thanks for rapid response.

For the Layout, it is not optimized but acceptable. 

The AGND could be disturbed by PGND switching noise.

I guess this will not lead to device damage.

Could you check if the device is working normally with lower input and output target？

Switching spec could be tested at lower voltage.

Also please tell me if there are more findings like oscillation or unstable.

Best Regards,

Fergus

Hi Jeff,

Is there any progress?

Feel free to connect if you have any questions.

Best Regards,

Fergus

Hi Fergus,

I've get the board and try to provide Vin =12V. First time is fine can provide 25V output.

SW pin waveform seem fine, but I don't save the waveform.

And 2nd time I add load about 200mA then Vin also short to GND.

I'm trying to apply sample and EVM for double check.

I have question about the FB resistor, I found we using 2.4Mohm and 100kohm, but we found datasheet using 2xxkohm and 1xkohm,

Is it impact IC normal work?

Thanks!

Jeff

Hi Jeff,

theoretically, the FB resistors only influence the output voltage target.

The main question is about the burn issue.

From former information, one is Vin short to Vout and another is Vin short to GND,

This reflects that the upper or down MOS have been burned.

One possible reason is shooting through.

Please compare the switching & driving waveforms of the EVM and your board to see the difference.

Would you mind send me a board and we can do the same test with you?

Please keep me informed if you have any update.

Best Regards,

Fergus

Hi Fergus,

Please compare the switching & driving waveforms of the EVM and your board to see the difference.

=> We are doing this but we are applying sample.

Would you mind send me a board and we can do the same test with you?

=> Sure, it glad to hear you willing to helping us. Please send me your address and I will prepare one board to you. Thank you!

Hi Jeff,

Could you send me an email?

My address is f-he@ti.com

I can also send an EVM to you directly.

Best Regards,

Fergus