TPS59641: VGFX does not start after VR_ON

Louis Defauw

Prodigy 50 points

Part Number: TPS59641

Hello,

We are currently testing a board with a E3826 CPU powered by a TPS59641 PMIC.

After VR_ON = 1, the VCORE is powered but not the VGFX. The GPWM signal seems to be tri-stated.

Here are the schematics:

The selection of the resistors/capacitors was done with the excel tool provided in the design package.

How could we make the VGFX powered at the same time as VCORE?

Regards,

Louis

over 4 years ago

0 Chasel Chen over 4 years ago

TI__Expert 5830 points

Hi Louis,

Can you provide L2 DCR information?

Also, can you check GFX SW to see if any pulse is issued?

Thanks

Chasel

0 Louis Defauw over 4 years ago in reply to Chasel Chen

Prodigy 50 points

Hi Chasel,

Here are the properties of L2:

I've just checked GFX SW and there is no pulse.

As the GPMW is in tri-state from the start up of the PMIC, I think that it is normal.

Thanks,

Louis

0 Chasel Chen over 4 years ago in reply to Louis Defauw

TI__Expert 5830 points

Hi Louis,

Thanks, it looks current sense network is ok.

Can you check pin32 GTHERM? and remote sense voltage. Normally, the case prevent controller from powering up is due to some fault has been seen before VR_ON, like thermal/OVP.. so please check by scope to see if any abnormal happens while VR_ON is high.

Thanks

Chasel

0 Louis Defauw over 4 years ago in reply to Chasel Chen

Prodigy 50 points

Hi Chasel,

I got in contact with the IMVP team of TI and they pointed out the problem with my circuit.

The CCSP3 pin was tied to 3.3V instead of GND.

Thanks for you support.

Regards,

Louis

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TPS59641: VGFX does not start after VR_ON