TIDA-01501: Current rating of L2 and BD1

Amr Elhadidy

Part Number: TIDA-01501

Hello,

the current Rating of BD1 is 15A while the current Rating of L2 is About 3A. Why are the Ratings highly differ whilw both carry the same current?

Thank you,

Amr

over 4 years ago

0 Huixin Wang over 4 years ago

TI__Intellectual 940 points

Hi,

BD1 is the diode rectifier bridge of PFC and L2 is the resonant inductor of LLC. these two devices don't have any relationship. please refer to the design guide for detailed calculation.

regards

huixin

0 Amr Elhadidy over 4 years ago in reply to Huixin Wang

Expert 1005 points

Hi,

on the schematic of LLC, the inductor is called L4. L2 is the choke inductor at the PFC stage which shares the same current BD1. OK, I check the design guide. Thanks for the hint.

Regards,

Amr

0 Huixin Wang over 4 years ago in reply to Amr Elhadidy

TI__Intellectual 940 points

I'm sorry that I made the mistake of L2 and L4. the L2 is the input common mode inductor and the current rating should be larger than the maximum input RMS current. the maximum input RMS current is 450W/90VAC = 5A AC. considering the power loss of L2, you should select an inductor with larger current rating which means smaller equivalent resistance.

this design uses BD1 with 15A current rating because this diode bridge has smaller forward voltage and better heat dissipation. for device selection, we need to keep some margin.

regards

huixin

0 Amr Elhadidy over 4 years ago in reply to Huixin Wang

Expert 1005 points

OK. Thank you very much.

Regards,

Amr

0 Huixin Wang over 4 years ago in reply to Amr Elhadidy

TI__Intellectual 940 points

you're welcome.

regards

huixin

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TIDA-01501: Current rating of L2 and BD1