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TPS62122: Question about output current

Seokmin Hong
Intellectual 485 points
Part Number: TPS62122

In the data sheet of TPS62122, there says Output Current is 75 mA.

I have two questions for this output current.

1. Is this mean TPS62122's maximum capable current is 75mA? What happens is loader takes more current than 75mA? Then IC can be damaged?

2. Normally, I learned when choosing buck converter's inductor, normally about 30% delta of Iavg.

If TPS62122's max capable current is 75mA, then is this mean I should choose Avg.current for 60mA System? (60mA * 30% delta = 78mA(about 75mA))

Or can I use 75mA for Average and peak current for 100mA (75mA * 30%) ? 

I

  • 0
    TI__Guru**** 191445 points

    Seokmin,

    TPS62122 is rated for 75 mA continuous output current.  The high side switch has cycle by cycle current limit of 250 mA typical and 200 mA minimum.  Therefore you maximum load current will be typically 250 mA minus one half ILp-p.  While you are correct that typically buck converters are designed for 30 % inductor ripple current, TPS62122 is designed to use 18 uH or 22 uH output inductor.  You can calculate the p-p inductor current for your application and then subtract one half of that from the current limit specification to determine the maximum load current before the current limit is activated.

  • 0 in reply to JohnTucker
    Intellectual 485 points

    Thanks for quick reply. Very helpful to me.