LM66200: Abnormal output

Lumina Gui

Part Number: LM66200

Tool/software:

Dear TI Engineer,

When we add input voltage on both VIN1 and VIN2 of LM66200, the output voltage is only 0.5V. But when removing any of the VIN, the output voltage is normal. Also, if there is no load at the output, the output voltage is normal.

The schematic is as below:

Can you help analyze the cause of this problem?

Thanks,

Kind Regards

11 months ago

0 Kunal Goel 11 months ago

TI__Guru* 79181 points

Hi Lumina

How much is load and load type?

How much is total output cap?

Do you have waveforms

How much is VIN1 AND VIN2

Regards

Kunal Goel

0 Lumina Gui 11 months ago in reply to Kunal Goel

Genius 3680 points

Hi Kunal,

The LM66200 is used on smart lock project and the testing is using an electronic load.

The VIN1 is 2.994V and VIN2 is 2.998V, they are both supplied by a DC power source.

I have found another post that mentions the situation that when VIN1 and VIN2 are very close, both the paths will conduct, and reverse can also flow. If both inputs are exactly equal, load sharing will be seen.

The link is https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1416862/lm66200-question-about-switching-between-vin1-and-vin2?tisearch=e2e-sitesearch&keymatch=LM66200#

However, in our actual testing, we found that the output is only normal when the voltage difference between VIN1 and VIN2 exceeds 70mV. Did it related to the description in the datasheet as below:

Thanks,

Kind Regards

0 Kunal Goel 11 months ago in reply to Lumina Gui

TI__Guru* 79181 points

Hi Lumina,

I think some kind of switching happening between reverse current blocking mode and coming out of that mode.

Regards

Kunal Goel

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LM66200: Abnormal output