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TPS61165: Help With LCD Max Backlight Current (Unespecified on DSheet)

Ignacio Diz
Prodigy 105 points
Part Number: TPS61165

Dear all

Were using tps61165 for Generating  backlight in our products

Now we received a TFT 320X240 display and Datasheet only shows Typical 15mA Current But Máximum Shows TBD (To Be determined)

I performed a test conencting a trimpot to the ISET pin and forced the backlight up to 70 mA and still dont burns

To set 15mA i placed 13 ohm, but we need a little bit more of backlight brightness

I like how lcd looks when we set to 50mA but we dont want to sacrifice reliability :(

How can i do to estimate a safe maximum value ?








TD022SREC6.pdf

  • 0
    TI__Intellectual 2140 points
    Hi,

    I believe you may have an early (not published) version of the datasheet. Could you please upload the latest datasheet version for the TPS61165 from TI.com?
    Regarding the maximum output current the TPS61165 can provide, it's not limited by the value set by RSET but by the input current limit. The worst case current limit is 0.96A (typical 1.2A). Section 9.1.1 in the datasheet has a detailed explanation of how to calculate the max output current for your application. The max output current will depend on the number of LEDs used (which will set the required output voltage), the input voltage and the inductor used. These components will determine whether or not the input current limit is sufficient or not.

    Regards,
    Angelos Tsiros
  • 0 in reply to Angelos Tsiros
    Prodigy 105 points
    No no!

    I mean that i dont know the maximum current of backlight LEDS!

    Everything its fine with TPS very reliable IC i love it
  • 0 in reply to Ignacio Diz
    TI__Intellectual 2140 points
    So, if I understand correctly, you are trying to determine the maximum current allowed for the LEDs you are using? I'm afraid I cannot answer that, you would need to get a complete spec from the LED manufacturer.