LM5170EVM-BIDIR: Boost mode issue

Surabadin Daengdon

Part Number: LM5170EVM-BIDIR
Other Parts Discussed in Thread: LM5171, LM5170

Tool/software:

Hello

I am studying the operation of the LM5170-Q board in Boost mode. I have closed the pins according to the manual and have shorted the 2 pad breakers on the back of the board. I supplied a voltage of 12 V to the LV side, while the HV side of the board is connected with Power resistor 30 ohm, 3000W. However, I encountered an issue where the output voltage on the HV side is only 11.719 V and the Boost mode LED in the top right corner is not illuminated., whereas I expected it to be around 48-50 V as specified in the manual.

The pins I have shorted: J2, J3, J4, J5, J8, J21, J25, J28, J29, J34, J35, J36, and J37.

1 month ago

0 Feng Ji 1 month ago

TI__Genius 14075 points

Hi Surabadin,

The image cannot be shown.

Please follow below modification and jumper settings. You need to change DIR for boost mode operation.

Please consider LM5171 which is the successor of LM5170.

Best Regards,

Feng

0 Surabadin Daengdon 1 month ago in reply to Feng Ji

Prodigy 30 points

Dear Mr. Feng Ji,

Thank you very much for your advice. Today, I followed your recommendation and added a 50k resistor (R4) to the board. However, I am still encountering the same issue. When I supply 12V to the LV side, the HV side only outputs 11.719V, and the LED for the boost mode remains unlit. Could this issue be due to my not using an E-Load, or might it be related to the power supply on the LV side?

0 Feng Ji 1 month ago in reply to Surabadin Daengdon

TI__Genius 14075 points

Hi Surabadin,

Can you share an image of your board and setup?

Best Regards,

Feng

0 Surabadin Daengdon 1 month ago in reply to Feng Ji

Prodigy 30 points

Hello Feng
This is the link to an image of the board and setup

Boardjumping.HEIC - OneDrive

Thank you

0 Feng Ji 1 month ago in reply to Surabadin Daengdon

TI__Genius 14075 points

Hi Surabadin,

Sorry, I cannot open the link.

Best Regards,

Feng

0 Surabadin Daengdon 1 month ago in reply to Feng Ji

Prodigy 30 points

Sorry, this is image

thank you

0 Feng Ji 1 month ago in reply to Surabadin Daengdon

TI__Genius 14075 points

Hi Surabadin,

I think the jumper is correct.

Does this work in buck mode?

You may need to check the signals to know why it is not working.

Best Regards,

Feng

0 Surabadin Daengdon 1 month ago in reply to Feng Ji

Prodigy 30 points

Hi Feng Ji

I just tested the Buck mode, but it didn’t work either. When I applied 48V to the HV side, the LV side had 0V, and the Buck mode LED in the top right corner did not light up.

When I checked the voltage on the nFault pin, it showed approximately 5V, but when I measured the 5V pin (J17 pin 25), I found that it only had 0.65V. Is this normal?

When
thank you

+1 Feng Ji 1 month ago in reply to Surabadin Daengdon

TI__Genius 14075 points

Hi Surabadin,

I suppose the EVM is damaged as 5V is not correct.

Maybe you need to check the bias supply first.

Best Regards,

Feng

0 Surabadin Daengdon 1 month ago in reply to Feng Ji

Prodigy 30 points

Hi Feng Ji
I would like to thank you for your assistance. I am now able to operate both Boost mode and Buck mode by applying an external 5V voltage to the 5V pin (J17 pin 25)

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LM5170EVM-BIDIR: Boost mode issue