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TPS61288: Efficiency estimation using WEBENCH

Kazuki Kuramochi
Expert 8840 points
Part Number: TPS61288
Other Parts Discussed in Thread: TPS61041, TPS61096, TPS61040

Hello Expert,

Our customer is looking for ultra low current output boost converter.
I found TPS61288 on TI.com and simulate efficiency using WEBENCH in last week.
Below is last week simulation result.
TPS61288_SIM (1).pdf

It seems very good efficiency but it is too good rather that datasheet's result at low current load condition.
So I re-simulation efficiency using the same condition of datasheet(Vout=16V and FB resistor follow this E2E thread )
But this simulation result is similar against datasheet as below.
WBDesign332.pdf
Therefore, I reconfirmed efficiency using first simulation parameter.
But  I got following result and it is completely different against first report even though I used same external components.
WBDesign331 (1).pdf

Then, I'd like to know about which simulation performance is similar as actual condition.

And, I'd want to know about whether both simulation result worth to trust.

Would you tell me answer for above questions?


Best regards,
Kazuki Kuramochi

  • 0
    TI__Expert 4760 points

    Hi Kazuki,

    The simulation of efficiency is not trustworthy. Please refer datasheet as the results are tested on bench. By the way, why do you choose 61288 for low current using? It is mainly used in high power application. 

  • 0 in reply to Yichen Xu
    TI__Expert 8840 points

    Hi Yichen,

    WEBENCH said this device has highest efficiency at Iout<5mA/2.8V<Vin<4.6V/Vout=18V so i chose it as attached first webench report.
    Is there other appropriate device?
    Also, our actual expected Vout is 20V and I confirmed TPS61041 and TPS 61096A's efficiency as attached webench report.WBDesign317.pdfWBDesign320.pdf

    But those devices have too bad efficiency against TPS61288's first report.
    After then, I look for device changing output voltage as 18V and WEBECH recommended TPS62188f as first report.
    So I focused TPS61288.
    Is there other recommended device for below required spec?
    ・Input voltage：approx. 2.8V~4.6V
    ・Output voltage： approx. 20V
    ・Output current：lower than 10mA
    ・Efficiency：Better than TPS61041.(especially less than 1mA range) 
    ・Smaller solution size and higher efficiency is better


    Best regards,
    Kazuki Kuramochi

  • 0 in reply to Kazuki Kuramochi
    TI__Expert 4760 points

    Hi Kazuki,

    For your application, tps61288 has the worst efficiency, about 65% between 0.5mA to1mA, see figure 6.3 in datasheet. Comparing figure 1 in tps61040 datasheet and figure 2 in tps61096 datasheet, the efficiency of tps61040 is higher, about 82% when Vin =3.6V, Vo=18V, Io=0.5mA to 1mA. I think tps61040 is better for you application.

  • 0 in reply to Yichen Xu
    TI__Expert 8840 points

    Hi Yichen,

    I confirmed TPS61040 by WEBECH with following expleind their target spec.
    ・Input voltage：approx. 2.8V~4.6V
    ・Output voltage： approx. 20V
    ・Output current：lower than 10mA
    ・Efficiency：Better than TPS61041.(especially less than 1mA range) 
    ・Smaller solution size and higher efficiency is better
    Then, I got below result but efficiency performance is same as TPS61041's result.
    WBDesign335.pdf

    Why do you recommend TPS61040 instead of TPS61041?


    Best regards,
    Kazuki Kuramochi

  • +1 in reply to Kazuki Kuramochi
    TI__Expert 4760 points

    Hi Kazuki,

    The simulation of efficiency is not trustworthy. Please refer datasheet as the results are tested on bench.

    i recommend TPS61040 instead of TPS61041 because of inventory.

  • 0 in reply to Yichen Xu
    TI__Expert 8840 points

    Hi Yichen,

    Thank you for your explanation.
    I understand.

    Best regards,
    Kazuki Kuramochi