TPS65261: I cannot get the output values ​​I want.

Dear Sir,

Pls kindly let me check and get back to you soon. Thank you!

BRs

Lucia

Thank you, I'll be waiting.

Hi Nuri,

Thanks for your understanding! Could you measure the Vfb1, Vfb2 and Vfb3? Are the reference voltage correct? And could you pls show me the LX1 waveform when Vout is not correct?

BRs

Lucia

Hello Lucia,

The values ​​are as follows.

Vfb1 - 0.256V
Vfb2 - 0.252V
Vfb3 - 0.242V

Below is the LX1 waveform.

Hi Nuri,

Pls kindly let me check and get back to you during these days. Thank you!

BRs

Lucia

Hi Nuri,

Pls try below:

(1) TPS65261 has average AC simulation model. Pls kindly check the loop stability performance and run the simulation to see if the loop is good.

(2) Pls kindly check whether there is any solderability issue of the device and the components, especially Ccomp and Rcomp.

(3) Is this issue happen for one board or all boards have this issue?

Thanks!

BRs

Lucia

Hello Lucia, I have checked and there does not seem to be any problem. I have 4 identical circuits installed and I get the same error on all of them.

Hi Nuri,

Thanks for your feedback. Pls kindly let me check and get back to you during these days. Thank you!

BRsLucia

Hi Lucia,

I couldn't do the simulation. However, I checked the Ccomp and Rcomp components and soldering, everything seems to be as it should be. I suspect my coil usage. AIML-0805HC-4R7M-T, do you think this coil is suitable?

Note: When I attached a coil whose value I didn't know (estimated 100uH), I got 1.1Volt output on the 1.0Volt line. When I attached it to the 1.8Volt line, I got 1.5Volt output.