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TPS61040-Q1: Output voltage set

Seungan Lee
Prodigy 20 points
Part Number: TPS61040-Q1
Other Parts Discussed in Thread: TPS55340, TPS61040

Hello, 

I wanna design Boost circuit to increas voltage to 28V by using 5V.

in case of TPS61040-Q1, possible output voltage is 28V at maximum according to datasheet.

I think, it means there are no margin when I make the circuit.

Is there any problem to make circuit like below?

R1 = 2200Kohm

R2 = 100Kohm (or smaller)

L = 22uH

(output current = under 20mA)

Thank you.

  • +1
    TI__Genius 11500 points

    Hi Seungan,

    No problem to configure TPS61040-Q1 as 28V Vout.

    The concern is that when Vin = 5V and Vout = 28V, the max Iout is very close to 20mA. The margin is very small. Increase the inductor, such as 47μH, can make the max Iout a little bigger.

    Could you help confirm the needed max Iout in the application? Is the auto-grade mandatory?

    Regards

    Lei

  • 0 in reply to Lei Zhong
    Prodigy 20 points

    Thank you for your feedback.

    I'm under check the needed max Iout w/ supplier(piezo speaker manufacturer).

    When I measured real consumption current, I need 7.3mA(speaker operating current) and 10mA(for piezo Driver, Maximum value).

    I means, over 17.3mA_min should be guaranteed.

    As you pointed, I think that current margin can be problem to use TPS61040-Q1, too.

    If so, would it be okay to use the TPS55340 instead of the TPS61040?

    for reference, we should use Auto-grade components(AEC-Qual).

    Thanks and Best Regards,

    Seungan Lee.

  • 0 in reply to Seungan Lee
    TI__Genius 11500 points

    Hi Seungan,

    If the package size of TPS55340 is acceptable, there will be no concerns at all for TPS55340's max Iout when Vin = 5V and Vout = 28V. It's much larger than 20mA.

    Regards

    Lei