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TPS61021A: Can I use this part with LiPo batteries?

Denis Govorkov
Prodigy 10 points
Part Number: TPS61021A
Other Parts Discussed in Thread: TPS61022, , TPS61230

Hello.

I want to use that boost converter for a gsm/gprs module which has 2A current peaks during transmission (I suppose it's quite standard usecase for such IC). So my incoming voltage will be between 2.8-4.3 V. I'd like to get 4V from this converter. I know about  TPS61022, but it's much more expensive here.

Datasheet says that incoming voltage can be from 0.5V to 4.4V, but, the workbench app allows to choose it only less than 3.6V. And all figures in the datasheet covers voltages under 3.6V. Would it work for me?

  • 0
    TI__Genius 9046 points

    Hi Denis,

    Yes you can use VIN ranging from 0.5V to 4.4V, it is ok to use Vin higher than Vout as the device enters pass-through mode by turning on HSFET. VIN=4.4V is an allowed case. Please note when VIN>VOUT&VOUT>1% of setting value VOUT will be larger than 4V;

    Another point is TPS61021A's current limit is too small for your case. For Vin=2.8V to Vout=4V, the maximum output current is only about 1.8A. 

    Calculation:

    VIN,min=2.8V

    VOUT=4V;

    IIN,MAX=ILIM,min=3A

    Assume efficiency in the worse case is 85%

    IOUT,MAX=VIN*IIN/VOUT=1.785A

    For other device which is able to cover your case, you could look at TPS61230

    -Wenhao

  • 0 in reply to Wenhao Wu
    Prodigy 10 points

    Thanks, TPS61230 looks good. Could you please explain what happens if vin is greater that set output value? It doesn’t have pass through mode, but there is so called zero duty cycle

  • 0 in reply to Denis Govorkov
    TI__Genius 9046 points

    Hi Denis,

    Please kindly refer to datasheet 8.4.3. Zero duty cycle is same as pass-through mode. Both will turn on HSFET eternally. 

    -Wenhao