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TPS92075 PWM dimming and SPICE model

Cedric Decouen
Prodigy 210 points
Other Parts Discussed in Thread: TPS92075, TPS92074, LM3445, LM3444

Hello, does someone have an example for TPS92075 dimming with a PWM signal? I've even read the TPS92074's app notes, but I've only found a 0-3V analog dimming solution. I think I could start from here, but if someone has the ready-to-use solution, it's better this way.

Is there a spice model of this device, so that I can can simulate the behavior of the system?

Kind regards to those how read this post... And answer.

  • 0
    TI__Intellectual 1115 points

    TPS92075 TPS92074 Briefing.pdfHi Cedric, The 0-3V Analog dimming is the best way to implement dimming with a PWM signal and the TPS92074 and/or TPS92075. You simply filter the signal and apply it as an alanog input to the converter and circuitry.  This series of controllers does not have a PWM input and other PWM dimming methods are not easily incorporated. (See pages 27,28,29 of the attachment). If you really want to DIM using a PWM signal you could consider the LM3445 with a valley fill soltuion. This is a popular method to obtain power factor and have a simple method to dim using a PWM signal. Much of the standard EVM circuitry can be removed if you are not TRIAC dimming, then a PWM signal can be fed directly to the DIM pin.

  • 0 in reply to Tim Sullivan
    Prodigy 210 points

    Thanks Tim,

    I will use the same board for two projets : one with a triac dimming, and one with a PWM dimming. The choice of the options will be made in production.

    A question remains : do you have a SPICE model for the TPS920075? It will be very helpfull for the system's desgin.

  • 0 in reply to Cedric Decouen
    TI__Intellectual 1115 points

    Hi Cedric, I'm sorry that we do not have a SPICE model for the TPS92075. I believe we have one for the LM3445/LM3444 which would give you some of the functionality, but not that tracking line synchronized reference - just the peak current, constant off-time control.

  • 0 in reply to Tim Sullivan
    Prodigy 210 points

    Thanks Tim, do you have an idea on how to use those spice model the best way in order to fit the TPS92075?

  • 0 in reply to Cedric Decouen
    TI__Intellectual 1115 points

    Hi Cedric, You could manually make a simple ramp reference that you could feed in to F2 that ran at the same frequenc as the line - and that would be pretty close. You would need to be mindful of the reference voltage - which is .75V max on the LM3445 and is 1V on the TPS92075 - but you could simply scale the sense resistance appropriately.  What aspects of the operation are you wanting to simulate?