TPS65217: Changing LDO outputs

Mali Kanchan

Part Number: TPS65217
Other Parts Discussed in Thread: TL5209

Hi everyone,

I am using TPS65217C on my board and I have used the Beagle bone black as my reference. I am using Li-Ion battery to power the system and will get charged simultaneously.

To increase the efficiency I want to use VBAT from 3V - 4.2V, so that I changed the UVLO to 2.73V and maximum charging limit to 4.2V. For this range of VBAT I changed the LDO2 and LDO4 output to 2.8V. After this change board worked fine for 2 days, but later voltage at LDO2 and LDO4 is 0V and respective pins also got shorted to GND. This happened with 2 boards.

Could you please tell the reason behind this behavior

Thank you

10 months ago

0 Brenda Diaz 10 months ago

TI__Mastermind 20076 points

Hi,

Are you using the same exact schematic design as the BeagleBone Black? If not, could you list the hardware differences? Here are some additional questions:

What is the TPS65217 full orderable part number?
What are you supplying with LDO2 and LDO4?
Did you save the new register settings (UVLO, LDO2/4 output voltage) into the EEPPROM so they become the default settings?

Thanks,

Brenda

0 Mali Kanchan 10 months ago

Prodigy 70 points

"TPS65217C TI 2CI G6KZ G4" this is the marking on the PMIC.

SYS_5V is input to the LDO2 and LDO4. Output of LDO4 is given to enable pin of TL5209.

Yes all register settings are saved into EEPROM. So they behave as defaul settings.

0 Mali Kanchan 10 months ago in reply to Mali Kanchan

Prodigy 70 points

I have not done the different board using TPS65217C. I am using beaglebone black board, there I am facing this issue.

0 Niko Alatalo 10 months ago in reply to Mali Kanchan

TI__Genius 13160 points

Hi Mali,

US has a public holiday today February 19th so Brenda will get back to you in the next couple of days. Thank you for your patience.

regards,

Niko

0 Brenda Diaz 10 months ago in reply to Mali Kanchan

TI__Mastermind 20076 points

Hi,

It is not recommended to change the output voltages of LDO2 and LDO4 in the Beagle board as those LDOs could be supplying ICs and signals that are expecting 3.3V. For example, LDO4 also supplies VDDA3P3V_USB0 on the AM335x.

Thanks,

Brenda

0 Mali Kanchan 10 months ago

Prodigy 70 points

Thank you Brenda

I want to utilize the full battery range from 3V to 4.2V. How can I use it without changing the LDO output voltages.

Regards

Mali Kanchan

0 Brenda Diaz 10 months ago in reply to Mali Kanchan

TI__Mastermind 20076 points

Hi,

If any of the PMIC rails is configured to output 3.3V, the corresponding input supply must be higher to meet the input-output headroom requirements. One option to evaluate could be adding a buck-boost to supply the rails that are configured to output 3.3V.

Thanks,

Brenda

Because of the holidays, TI E2E™ design support forum responses will be delayed from Dec. 25 through Jan. 2. Thank you for your patience.

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TPS65217: Changing LDO outputs