LM5010: LM5010

Matic Mohorcic

Part Number: LM5010

Tool/software:

Hi!

I made a 12V step down design with LM5010. Converter is quite tricky because it is referenced to -48V. Converter feed two fans with around 0.5A total courrent consumption. Sometimes Converter simply fail.

What could be the root cause of the failure?

Vin voltage range: -40V to -60V

Schematics:

choke details: CLF10040T-101M-D

11 months ago

0 EricLee 11 months ago

TI__Guru 58851 points

Hello Matic

Would you please let me know the failure condition and describe in detail what happens after the failure ?

If any waveforms, please share them for me.

-EL

0 Matic Mohorcic 11 months ago in reply to EricLee

Prodigy 10 points

Converter worked normally some time then failed. Converter was running 2x Delta fans AFB0812VHDVCX. Now LM5010 generate only few volts.

I disconnected load. SW node voltage seems not right. There is 50V at the input of LM5010 and 4V at the output

0 EricLee 11 months ago in reply to Matic Mohorcic

TI__Guru 58851 points

Hello

It works properly again after restarts ?

If not, can you check which pin is damaged ?

-EL

0 Matic Mohorcic 11 months ago in reply to EricLee

Prodigy 10 points

No it does not work after restart. PIN 1-10 resistance (top fet) on the good and bad IC is the same - 4k7

0 EricLee 11 months ago in reply to Matic Mohorcic

TI__Guru 58851 points

Hello Matic

Then, I think the device is damaged by an EOS.

Please check if any over shoot between the VIN and RTN pins during power on or during power off.
Also, please use a probe with spring ground (pigtail) and check if any over shoot between the SW and RTN pins when switching at full load.

-EL

0 Matic Mohorcic 11 months ago in reply to EricLee

Prodigy 10 points

LM5010 IC dies. We found out that short circuit or low impedance load also cause new LM5010 converter to fail. What could cause device to fail?

0 EricLee 11 months ago in reply to Matic Mohorcic

TI__Guru 58851 points

Hello Matic

Would you please capture the inductor current during the output short test ? The inductor might be saturated during the output short test.

-EL

0 Matic Mohorcic 11 months ago in reply to EricLee

Prodigy 10 points

replaced choke with WE 7447709101 but nothing changed. Device does not survive short circuit event.

0 EricLee 11 months ago in reply to Matic Mohorcic

TI__Guru 58851 points

Hello Matic

I hope you can capture the inductor current during the output short test. Also, please check V(SW-GND) is less than 75V or not during the output short test.

-EL