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TPS61043 driving 2 white LED. Efficiency vs Vin.

Horia Morariu
Prodigy 30 points
Other Parts Discussed in Thread: TPS61043, TPS61042

Dear colleages,

I am currently working on a particular application where using 2 white LED as backlight, powered from 3V battery.

I am just wondering if TPS61043 is appropriate for this application (as it seems to be, at least from the datasheet).

My question is basically addressed to an AFE from TI (or anyone with experience on this device): I need to know if you have characterized this chip working with 2 white LED instead of 4.

An efficiency graph will be usefull, showing TPS61043 with 2 white LED, powered from 2V to 5V.

Thank you in advance for your quick support.

Cheers, Horia.

  • TI__Guru*** 148885 points

    This family of LED drivers was designed to boost to much higher votlages.  Although we have not tested it, I expect the IC to opearte but it will have lower efficiency.  What efficiency range are you expecting/needing?

  • in reply to Jeff F
    Prodigy 30 points

    Hello Jeff.

    I would expect an efficiency of minimum 75%, up to 95%.

    That this IC was not characterized when working with only 2 white LED in series (used as backlight for a small LCD), powered from 2,4V (2 NiHM accumulator in series) to 5V (USB).

    Maybe not a full characterization is expected from Texas Instruments, but some measurements at the specified power supply voltages, at room temperature, showing Vin/Iin/Eff.

    Thank you in advance for your quick support.

    Horia Morariu

  • in reply to Horia Morariu
    TI__Mastermind 36110 points

    Although we did not expect customers to use the TPS61043 with only 2 LED (typical applications are 4 in series), the TPS61043 will work well with this application.  You will be able to modify the existing TPS61042 EVM with your chosen capacitors and inductors and test its performance to ensure it meets your requirements.  A TPS61043 EVM does not exist.  The difference between the TPS61042 and TPS61043 is that the TPS61042 overvoltage protection is 29V and the TPS61043 overvoltage protection is 18V.  Either will work for your application.

    You can order the EVM from the eStore or contact your local TI representative for assistance.  https://estore.ti.com/Default.aspx