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TPS92692EVM-880: Constant voltage possible? Spread spectrum for dimming?

Sebastian Eckert
Prodigy 40 points
Part Number: TPS92692EVM-880

Dear forum members,

I've got a question regarding the abovementioned kit, but I'm completely open to suggestions about other parts that might work better here.

I'd need a solution to do PWM dimming with spread-spectrum for LED strips that are voltage-driven, though. Is there a way to generate a spread-spectrum modulated dimming signal for a 24V supply?

Best regards and thanks in advance

Sebastian

  • 0
    TI__Mastermind 25500 points

    Hello Sebastian,

    Yes, that device can be set up for a voltage output. You just connect CSP to Vout and use a relatively low resistor value between CSP/CSN (I have used 41.2ohm, this is to reduce error from the CSP/CSN pin currents) and place another resistor from CSN to ground to see the output voltage. You will also want to try and have a pretty high bandwidth.

    Regards,

    Clint

  • 0 in reply to Clinton Jensen
    Prodigy 40 points

    Hello, Clint.

    Thanks for your reply!

    It's very useful to know this, and definitely a step in the right direction, but I'm a bit hesitant to consider this resolved because we would like to apply a spread spectrum modulation to the dimming signal, not only to the underlying switching frequency of the DC/DC-converter. Is that possible? Are there any solutions, apart from generating such a signal in software?

    Thanks in advance

    Sebastian

  • 0 in reply to Sebastian Eckert
    TI__Mastermind 25500 points

    Hello Sebastian,

    You can apply any type of square wave you would like to the PWM pin, including spread spectrum. I am not aware of any cookbook solutions for this however, it would need to be done with software.

    Regards,

    Clint

  • 0 in reply to Clinton Jensen
    Prodigy 40 points

    Hello Cllnton,

    thanks for this clarification. Then I can consider the issue resolved, and we'll need to work something out on that basis, with an external controller added that generates the dimming signal.

    Thank you for your help,

    Sebastian