TPS53647: Maximum output current limitation

prabhjot kaur

Part Number: TPS53647
Other Parts Discussed in Thread: CSD95480RWJ, TPS53667,

Hello Sir/ Mam

We are currently using TPS53647RTAR with four CSD95480RWJ schematic attached for your reference for 108 A current presently . Now we want to use same design for 150 A current as CSD95480RWJ supports maximum 70A.

But TPS53647RTAR datasheet says it can be used for 120 A only. Can you please tell what is the current limitation for it . Can we use same design for 150 A or not , If we cannot use it for 150 A can you suggest some alternative for 150 A.

over 1 year ago

0 Chris Bartuska over 1 year ago

TI__Intellectual 2060 points

Hi Prabhjot,

The TPS53647 does have a maximum recommended current of 120A, I would recommend the pin-to-pin replacement TPS53667 which has a recommended maximum current of 180A. This is a 6 phase controller, but can still be configured in 4 phases.

Best Regards,

Chris Bartuska

0 prabhjot kaur over 1 year ago in reply to Chris Bartuska

Prodigy 140 points

Thank you for your Response

Also What exactly is the limitation with part TPS53647 as Mosfet are capable for 70A current but PMIC is limited to 120A.

Is the same current limitation applies if we use 4 phases of Part TPS53667?

As we saw in Datasheet snap attached vout=0.88V and Imax=120A

0 Chris Bartuska over 1 year ago in reply to prabhjot kaur

TI__Intellectual 2060 points

Hi Prabhjot,

According to the electrical characteristics in the datasheet, it looks like the maximum voltage that can be set on F-IMAX pin is Vref (1.7V).

If you use the equation for IMAX in the datasheet, the recommended maximum would be:

1*256 - 0.5 = 255.5A

Sorry for the confusion, my previous post was incorrect. The IMAX values in the table sent in the last post must just be examples.

Best Regards,

Chris Bartuska

0 prabhjot kaur over 1 year ago in reply to Chris Bartuska

Prodigy 140 points

Hello

I'm bit confused that which part are you talking about TPS53647 or TPS53667 . And if you are talking about part TPS53647 that means we can use same part for drawing 150A current with 4 phases.

0 Chris Bartuska over 1 year ago in reply to prabhjot kaur

TI__Intellectual 2060 points

Hi Prabhjot,

Sorry, the TPS53647 has a IMAX limit of 255.5A. You can use the same device for drawing 150A.

Best Regards,

Chris Bartuska

0 prabhjot kaur over 1 year ago in reply to Chris Bartuska

Prodigy 140 points

Thank you for clarification

So, finally we are going with Part TPS53647 with Vout=0.88V and Iout=150A

we just have to change R-IMAX resistor to 21K to change VF-IMAX value to 1V so that we can set maximum output current to 150A

Please confirm that is my understanding is correct or not ?

0 Chris Bartuska over 1 year ago in reply to prabhjot kaur

TI__Intellectual 2060 points

Hi Prabhjot,

Your understanding of the R-Imax is correct, replacing the R-Imax with a 21k ohm resistor would result in 1V on the pin for 150A Imax setting.

However, looking into the design of this system, the CSD95480 has a recommended TDC current of only 25A (not 70A). If you are attempting to draw a continuous 150A, this solution will not work. You would need to use the CSD95410 which has a 40 A continuous output. We would also recommend changing to a 5-phase solution for the best thermal performance.

Best Regards,

Chris Bartuska

0 prabhjot kaur over 1 year ago in reply to Chris Bartuska

Prodigy 140 points

Hello

What you mean by recommended TDC current of only 25A (not 70A). As Datasheet says 70A continuous current.

0 Chris Bartuska over 1 year ago in reply to prabhjot kaur

TI__Intellectual 2060 points

Hi Prabhjot,

"Continuous output current" in this datasheet is defined as up to 500us pulse duration, the lifetime of the power stage may be reduced by operating in DC RMS conditions for longer periods. For systems with mostly continuous operating current, TI recommends a maximum of 25A RMS thermal design current (TDC) for the CSD95480. If this applies to your system, we recommend upgrading to CSD95410 (40A TDC).

Best Regards,

Chris Bartuska