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TPS61041-Q1: Load Current calculation

Fayis Mohammed
Prodigy 20 points
Part Number: TPS61041-Q1
Other Parts Discussed in Thread: TPS61041

TPS61041-Q1 has load current rating of 250mA, I need to design a circuit with load current 120mA, but with the calculation which was mentioned in

Datasheet, I'm not able to meet 120mA, seems like Inductor is not playing much role in load current.

with higher inductance maximum switching frequency is getting reduced thus the load current,  

Vin(min) = 3.3 V

Vin(typ)= 3.3V

Vout= 9V

Will you please provide the calculation for 120mA Load current ?

- Thankyou Slight smile

  • 0
    TI__Expert 5180 points

    Hi Fayis,

    TPS61041 should always work in DCM mode, which means there is one max output load current. The inductor current will always reach the peak limit (Ip) every duty cycle. So the waveform of inductor current increase and decrease if fixed. The converter need to adjust the time which the current is discontinuous to adjust load current. Therefore, the max load current happens when the inductor current is DCM and there is no discontinuous period. If the load current is higher than this value, the output cannot be regulated. 

    Besides, 250mA refer to input inductor peak current limit. For your application, the input average current is about 300mA which is even higher than 250mA. 

    Best Regards,

    Eric Yue

  • 0 in reply to Eric Yue
    Prodigy 20 points

    Hi Eric,

    Thanks for the feedback.

    So it's clear that at 9V output, the IC cannot deliver 120mA.

    Regards,

    Fayis

  • 0 in reply to Fayis Mohammed
    TI__Expert 5180 points

    Hi Fayis,

    Yes, your understanding is right with TPS61041. I have also recommended some alternative devices for your FAE and for your reference. Thanks.

    Best Regards,

    Eric Yue