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TPS61096A: Why is this efficiency lower than TPS61041?

Part Number: TPS61096A
Other Parts Discussed in Thread: TPS61041,

Hi Expert,

This is Koki Tsushima.

My customer will evaluate EVM of TPS61096A, but wants to know why this efficiency lower than TPS61041 at Vout 12V, Iout 1mA ?

As fig.1 that efficiency is around for 80%.

 

It seems to be lower than TPS61041 (Although some condition is different).

Could you tell me the reason why this is low and just around 80%?

Customer think this is due to 2ch level shifter was powered by Vout, but this consumption is just 3uA, therefore, it should not be correct.

In addition, customer want to use for light load.

If customer ignore efficiency than 100mA, do you have ideas which can improve the efficiency more for less than 100mA?

Best regards,

Koki Tsushima 

  • Hi Koki-san,

    I think the reason why TPS61096A efficiency is lower than TPS61041 in datasheet is TPS61096A's tested inductor is 2.2uH while TPS61041 inductor is 10uH. Smaller inductor will cause slower current ramp up rate, besides TPS61041 current limit is lower than TPA61096A. If TPS61096A inductor is larger (4.7uH or 10uH), efficiency will be better as well. For customer's application, TPS61096A is more suitable, because of its ultra-low quiescent current. The lower the load current is, the advantage of low IQ will be more obvious.

    For light load application, typically inductor value and feedback resistor value will have influence. Larger feedback resistor will improve the efficiency, but decrease the robustness against noise. Larger inductor will have larger size and cost. It is a trade off process.

    Best Regards,

    Eric Yue

  • Hi Eric-san,

    I did not notice that L was different.

    Your answer was helpful to understand.

    Thanks!

    Koki Tsushima

  • Hi Koki-san,

    Thanks for reaching out on E2E, please notice me if there is any more concern.

    Best Regards,

    Eric Yue