TPS65400: PGOOD is low, all other output coming fine. can unused switcher impact?

Sarika Gurnani

Part Number: TPS65400

Hello,

I am using 3 outputs of PMIC TPS65400. 4th output is unused. ENSW4 (enable of SW4) is pull low.

Getting 3 outputs ok but PGOOD is below 1V. If I pull up Pgood with 10k at 3.3V then also same case.

Please let me know if this is because of 4th unused switcher or any other reason.

thanks

0 Shuai Fan over 2 years ago

It is caused by 4th unused switch.

Shuai

0 Sarika Gurnani over 2 years ago in reply to Shuai Fan

Hi Shuai,

as per datasheet,

9.2.1.2.5 Unused Switchers
If the default setting active ENABLE of ENABLE_PIN_CONFIG is selected, ENSWx for unused switchers must
always be tied low.

I've done same, still should I get Pgood low because of unused switcher?

thanks

0 Shuai Fan over 2 years ago in reply to Sarika Gurnani

Yes. PGOOD is the output of the AND gate of SW1,SW2,SW3,SW4 by default.

If SW4 is unused. You can use programming by PMBUS.As shown below.

0 Sarika Gurnani over 2 years ago in reply to Shuai Fan

Hi Shuai,

Thanks for explaining Pgood.

Kindly let me know if there is any option to make this Pgood high if I am not using 4th switcher and don't want to configure with PMBUS.

Actually, in my design, I am not using PMIC with programming.

0 Shuai Fan over 2 years ago in reply to Sarika Gurnani

It is a little bit difficult. Show me your schematic.

Shuai

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