[TPS652510] PGood when Buck is disabled

Benjamin Mak

Other Parts Discussed in Thread: TPS652510, TPS65253, TPS65252

Hi Team!

I am planning to use a TPS652510. However, I was not sure about the PGOOD pin when one of the bucks is disabled. I would imagine that the PGOOD output would only depend on the state of the remaining two bucks, but I am not sure.

How does the PGOOD pin react when the TPS652510 has 1 of the buck converters disabled?

Thank you for your support!

Ben

over 12 years ago

0 Gregory Watkins over 12 years ago

TI__Expert 4005 points

PGOOD is only asserted when all 3 converters are enabled and operating above 90% of desired output voltage. If one converter is disabled you will not see PGOOD go high.

0 Benjamin Mak over 12 years ago in reply to Gregory Watkins

TI__Intellectual 2190 points

Thanks for the help!

0 Benjamin Mak over 12 years ago in reply to Benjamin Mak

TI__Intellectual 2190 points

Hi Greg,

I had a question about this. What is the recommended connections for an unused rail? I understand that you can pull down the EN pin. However, what should I do with the other pins?

Thanks,

Ben

0 Gregory Watkins over 12 years ago in reply to Benjamin Mak

TI__Expert 4005 points

If not using a rail, EN should be tied to GND. The rest of the unused pins can be either floated or grounded. I would ground: VIN, FB, and COMP. Float: SS,Rlim,BST,LX.

The unused rail should not be Buck 2, the internal bias circuitry is powered from VIN2.

If the customer does not require automatic PFM/PWM mode, i would suggest they look into TPS65252 and TPS65253. They are similar to TPS652510 but only feature 2 converters, the change could potential save the customer board space and reduce costs.

Power management

Power management forum

[TPS652510] PGood when Buck is disabled