LM5060: Support needed

Alfred Logico

Part Number: LM5060

Hi Team,

I received an inquiry from our customer when they used our LM5060. Below is the summary of the application and issue they are facing.

We are using LM5060 to drive 4 Fets- act as switches.

I set the OCP to about 160A.

Upon reaching that level, I observed that, instead of latch, the gate drive retry and end up damaging the FETs and the LM5060.

BBU_PWR comes from a DC Source.

Q1800 to Q1805 are Power FET that connects the BBU_PWR to the converter.

In case of any fault in the converter the Q1800 to Q1805 will disconnect the BBU_PWR to converter.

Can you help provide feedback why they are facing the failure?

Thanks!

Best Regards,

Alfred

over 5 years ago

0 Rakesh over 5 years ago

TI__Guru* 95911 points

Hi Alfred,

Can you please share the schematic with component values and MOSFET part number. What is the timer capacitor value?
Can you get a test waveform with Vout, Vgs, Timer voltage and the input current. Please place schottky diode between Vout and DC_GND and check again.

Best Regards,
Rakesh

0 Alfred Logico over 5 years ago in reply to Rakesh

TI__Expert 4230 points

Hi Rakesh,

Here is the schematic with component values. I am working on getting the wave forms.

R1820 is being tuned for correct OCP level. Vin is 60V – 30V and OCP level is 180A. Any comments on this?

Thanks!

Best Regards,

Alfred Logico

0 Alfred Logico over 5 years ago in reply to Alfred Logico

TI__Expert 4230 points

Here are the waveforms:

0 Alfred Logico over 5 years ago in reply to Alfred Logico

TI__Expert 4230 points

Hi Rakesh,

I was hoping to follow-up on this. I hope I can get feedback today.

Thanks!

Best Regards,

Alfred

0 Rakesh over 5 years ago in reply to Alfred Logico

TI__Guru* 95911 points

Hi Alfred,

It shows abnormal behavior. For overload event, the timer should continue further and settle at 4V (similar to Figure 38 in the datasheet). Here, the timer is resetting and starting again from zero volts. It can only happen if the device resets.
Have you checked OVP or UVLO voltage level at the device which may cause device to reset.

Also want to check - whether the FET failed while capturing this test waveform?

Best Regards,
Rakesh