LDO and switching converter's load current question

Jacky Chen29

Genius 4735 points

Other Parts Discussed in Thread: TPS54229E, TPS54229

Hola,

My application is as below：

Vin = 8.4V

Vout = 5.2V

The load current is about 0.15A ~ 0.16A when I'm using LDO of MIC5207.

But the load current only remains 0.1A when I'm change to using switching converter of TPS54229E.

Does this load current changing phenomenon is relation to the power source different？

How strange, the load current will be changed based on power source changing！Is this make sense？or something wrong？

over 8 years ago

0 JohnTucker over 8 years ago

TI__Guru**** 191445 points

I don't understand your question. It would help if you post a more detailed description of your system along with the schematic.

0 Jacky Chen29 over 8 years ago in reply to JohnTucker

Genius 4735 points

Hola John,
Thank you for your reply. May you share your experience for the above phenomenon？Is this normal？

0 JohnTucker over 8 years ago in reply to Jacky Chen29

TI__Guru**** 191445 points

Can you tell me about your load? Is it purely resistive? Can you post your schematic and perhaps some waveforms?

0 Brigitte over 8 years ago

TI__Guru 59755 points

Hello Jacky,

Is it possible that you mean with load current the current that is flowing into the MIC5207 or TPS54229? If this is the case, we call this supply current because it is supplying our IC.
If you mean the current going into the MIC5207 or TPS54229, it is normal that the supply current of a buck converter with this input to output voltage ratio is smaller than with an LDO because the efficiency of a buck converter is better. The efficiency of the LDO in this case is below 62%.

Best regards,
Brigitte

0 Jacky Chen29 over 8 years ago in reply to Brigitte

Genius 4735 points

Hola Brigitte,

Thank you very so much for your kind reply.

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LDO and switching converter's load current question