TPS63020 problem

Luis Sousa

Hi, this is my first post :)

I have a problem with the TPS63020 converter. Basically it does not work.

I have read datasheet and pcb layout recomendations. I have a switch to switch the enable pin from VINA to GND to enable ou disable the chip. When i first powered on the chip and enabled it, it did not anything. And after that, i measured the VINA Pin and to my surprise the pin was now grounded.. (what??) before powered it, it was not grounded.

I have testes 2 pcb and all happened to both.

Below is my pcb circuit. On teft side is just a lipo charger.

over 10 years ago

0 Florian Feckl over 10 years ago

TI__Expert 7110 points

Hi Luis,
i guess blue is your copper top and green is your copper bottom.

For the layout of the SMPS, it is very important to keep an eye on the analog design, like the ground routing.
The Pin AGND should be your star point between analog and power ground. You should properly connect the power to e.g. the GND plane.
Please see datasheet page 19.

Here is an article explaining this: www.ti.com/.../slyt614.pdf

0 Luis Sousa over 10 years ago in reply to Florian Feckl

Prodigy 30 points

Hi Florian,

thank you for the help.

I know my design is not the best but at least i thought it could work. My schematic is exactly as shown on the datasheet and i can´t explain why it dont work..

0 Florian Feckl over 10 years ago in reply to Luis Sousa

TI__Expert 7110 points

The schematic, however, is half the job.
For any analog HF circuit, the layout is the 2nd critical step to consider. This is because you can add a lot of parasitic's to your circuit that change the behavior totally.

0 Luis Sousa over 10 years ago in reply to Florian Feckl

Prodigy 30 points

Thank you very much. I have remade the pcb layout and now it works!

You are awesome ;)

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TPS63020 problem