TPS65185 fails to start

VDM

Intellectual 325 points

Hi,

My power-up sequence :

WAKEUP = 1 / PWRUP = 0 / VCOM_CTRL = 0

wait a few seconds

WAKEUP = 1 / PWRUP = 1 / VCOM_CTRL = 0

When I do this with no load, I got all voltages ok, and reading register POWERGOOD gives 0xFA.

But when I do this with my e-ink screen connected, I can see that all voltages ramp-up, and then falls down to 0V. Then reading POWERGOOD gives 0x00.

If I try to connect the e-ink display AFTER the startup sequence, then the voltages keep fine !

What can give such a situation ?
How to debug ?

Thank you for your help !

Best regards,
Vincent.

PS : what's the difference between setting 1 to the PWRUP pin and writing 0xBF to register "ENABLE" ? Is this a "OR" command ?

over 8 years ago

0 Richard Solarski over 8 years ago

TI__Genius 10885 points

This could be a soft-start fault or some other fault condition, do you see activity on the INT pin, and can you check the status of the INT1 and INT2 registers?

Yes, PWRUP (rising edge) and Active Bit are OR'd in the Global State diagram in Figure 24.

0 VDM over 8 years ago in reply to Richard Solarski

Intellectual 325 points

Hi,

Thank you for your answer.

I've managed to make it start, but I had to first enable the 3V3 output (which is connected the the e-ink 3V power input), and then every other voltages.

I'll try to confirm this next week.

0 Jayanth Kruttiventi over 8 years ago in reply to VDM

TI__Intellectual 1360 points

Hi,

It looks like WAKEUP and PWRUP pins are pulled to 3V3. If you dont have the 3V3 voltage the PMIC will not power up.

Thanks,

Jay

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TPS65185 fails to start