LM25149-Q1EVM-2100: Dual phase operation by using 2 EVMs

Yuta Kurimoto

Part Number: LM25149-Q1EVM-2100
Other Parts Discussed in Thread: LM25149-Q1

Hello Team,

Our customer want to evaluate dual phase operation by using 2pcs of LM25149-Q1 EVM but somehow they can't work well.

Can you please let me know the setup to perform dual phase operation by using 2 EVMs? They want to know how to connect each EVMs by picture or schematic.

Thanks,

Yuta Kurimoto

over 2 years ago

+1 Orlando Murray over 2 years ago

TI__Mastermind 22299 points

Hi Yuta,

Please do the following:

Remove Primary PG pullup resistor R12.

Unpower Secondary AEF (Remove R6)

Change Primary RCNFG to 54.9kΩ or 71.5kΩ. Change secondary RCNFG to 90.9kΩ (see Table 8-4 in datasheet)

Tie COMP together

Tie VOUT together

Tie Primary PG to Secondary PFM/SYNC

I'll be updating the datasheet with a dual phase example

Hope this helps,

-Orlando

0 Yuta Kurimoto over 2 years ago in reply to Orlando Murray

TI__Expert 8290 points

Hello Orlando,

Based on your comment, customer can perform dual phase operation now. But other question comes up.

>>Unpower Secondary AEF (Remove R6)

When they removed R6 and unpowered AEFVDDA, the device can't recognize the CNFG setting correctly.

(For example, When R6 is removed and they set the RCNFG=90.9kΩ, the device behave as RCNFG=41.2kΩ somehow.

Can you please confirm again if the R6 should be removed or not?

Thanks,

Yuta Kurimoto

0 Orlando Murray over 2 years ago in reply to Yuta Kurimoto

TI__Mastermind 22299 points

Hi Yuta,

Thats very strange. What are they seeing happen?

R6 only connects to VCC and AEFVDDA, also the AEF pins are isolated from the controller pins.

If the secondary VCC is fine, R6 should not affect configuration at all.

Let me know what they are seeing happen.

-Orlando

They can also remove CINJ and CSEN (C1 and C3) on the secondary to disconnect AEF from VIN.

0 Yuta Kurimoto over 2 years ago in reply to Orlando Murray

TI__Expert 8290 points

Hello Orlando,

Thanks.

I will send you customer's EVM circuit by email.

Regards,

Yuta Kurimoto

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LM25149-Q1EVM-2100: Dual phase operation by using 2 EVMs