LM5036: IC Overheating Problem

senthilkumar m

Prodigy 120 points

Part Number: LM5036

Tool/software:

Hi,

We have designed an isolated DC-DC converter with the following specifications:

Input Voltage: 60 V to 90 V
Output Voltage: 13.8 V / 40 A

However, we are facing an IC heating issue within just a few seconds of operation. Could you please suggest what might be causing this problem and how to resolve it?

Any guidance would be greatly appreciated.

Regards,
M. Senthilkumar

11 months ago

0 Hong Huang 11 months ago

TI__Guru 74075 points

Hi,

IC heating up, it means its bias current too high from the aux bias not take effect to substitute the LM5036 internal LDO. So you need to check if the aux bias voltage is high enough to bias the IC and to stop the internal LDO.

0 senthilkumar m 11 months ago in reply to Hong Huang

Prodigy 120 points

thank you , i will check and update you...

0 senthilkumar m 10 months ago in reply to senthilkumar m

Prodigy 120 points

Yes, the issue was due to the auxiliary bias voltage, which was caused by an IC solderability problem. This has now been corrected.

However, we are currently facing an issue with the over-current cut-off. When the load reaches the over-current limit, the transformer produces a hissing noise. The current cut-off and current limiting functions are working properly, but we would like to have your clarification on this behavior and your advice on a possible solution.

Thank you for your support.

0 senthilkumar m 10 months ago in reply to senthilkumar m

Prodigy 120 points

please reply to this quire...

0 Adhvaidh Aravind 9 months ago in reply to senthilkumar m

TI__Expert 6290 points

Hi Senthilkumar,

Our sincere apologies for the delay in our response. We appreciate your patience.

That's strange! Could you please probe CS pin, SW node, COMP pin, and output voltage? We would like to observe what happens when the over-current limit is hit. Please share both zoomed-in and zoomed-out screenshots of the waveforms.

Best,

Adhvaidh

Power management

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LM5036: IC Overheating Problem