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Original question:

LP5868: Alternative with constant current and Vin over 30V

TPS922053: Noise when using the TPS922053. Can it be further reduced?

Florian Hintermaier
Prodigy 30 points
Part Number: TPS922053

Hey everyone,

after a long search for the right LED dirver i am currently testing a TPS902253 using a PWM inuput and a analog output.

In the following u can see the signal measured across a resistor that is right before the LEDs (27uF left and 10uF right used as inductors in the circuit).
As you can see there is a high frequency noise with a max ripple of about 150 mV. (I also tried 39 uF but it doesn't get much better)

Now my question is: Is this to be expected from the TPS922053 or is this fixable to a degree by changing the overall setup.
If the later is the case i will gladly share my current setup with you guys.

All the best,
Florian

  • 0
    Prodigy 30 points

    Just so you get a better Idea what I mean. Here is the same measurement on with the same LEDs and similar power output with the ADP8140 form Analog Devices as LED Driver.
    Can i get a similarily "clean output from the TPS?

  • 0 in reply to Florian Hintermaier
    TI__Mastermind 23150 points

    Hi Florian,

    My understanding is you are not satisfied with the output current ripple even if you altered the inductor value with 27uH, 10uH and 39uH. Am I correct?

    If this is the case, may I understand what is the ripple value you have measured now and what is your target ripple value? Also, what is your input voltage / LED voltage / LED current setting?

    Best Regards,

    Steven