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TPS61160A: Maximal load current for Buck applications?

Isabelle Guitard
Prodigy 120 points
Part Number: TPS61160A

Hi all,

I am trying to determine the maximal load current that TPS61160A can deliver at about 8.3V.

The formula given in the datasheet at 8.2.1.2.1 Maximum Output Current gives me an impossible Iout max current.

I used the suggested 22uH inductor VLCF5020T-220MR75-1 and a schottky diode LSM115JE3/TR13 (forward voltage = 0.22V).

Can TPS61160A be used exclusively in Boost mode? If so, is there an alternate chip for Buck applications?

Here are my design specifications:

Nominal Vin = 12V

Nominal Iout = 180mA @ Vout=8.3V

The load is an LED backlight that consists of 9 parallel rows of 3 white LEDs each. Each row needs 20mA, so the load overall draws 180mA.

Thanks for your help.

Isabelle G

  • 0
    TI__Expert 4550 points
    Hi Isabelle,
    I'm afraid TPS61160A can only work in boost mode. In you application the input votlage is higher than output votlage, boost converter is not applicable. If you still want to use TPS61160A, there are two ways to try: 1. build a sepic convertor, we don't have reference design for sepic converter, but theoritically it should work. 2. add one front stage of buck converter, converter 12V into 5V , then cascaded with boost TPS61160A backlight driver, this is way is simplier.
    Hope this helps.
  • 0 in reply to Caryss Li
    Prodigy 120 points

    Caryss Li said:
    Hi Isabelle,
    I'm afraid TPS61160A can only work in boost mode. In you application the input votlage is higher than output votlage, boost converter is not applicable. If you still want to use TPS61160A, there are two ways to try: 1. build a sepic convertor, we don't have reference design for sepic converter, but theoritically it should work. 2. add one front stage of buck converter, converter 12V into 5V , then cascaded with boost TPS61160A backlight driver, this is way is simplier.
    Hope this helps.

    Hi Caryss,

    I will look into these options but I am trying to avoid external circuitry at the moment.

    Is there an alternative to TPS61160A that works in BUCK mode for backlight driver? I have not found any IC on the search tool.

    Thanks

    Isabelle 

  • 0 in reply to Isabelle Guitard
    TI__Expert 4550 points
    HI Isabelle,
    We don't have Buck mode backlight drivers. You may try to find buck drivers instead of backlight drivers. Please post another thread without menstioning TPS61160A, to see if others could help you.
    Hope this helps.