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WEBENCH® Tools/TPS568215: TPS568215RNNR

Hareesh Panakkal
Prodigy 210 points
Part Number: TPS568215

Tool/software: WEBENCH® Design Tools

Hi All, 

I am trying to simualate the TPS568215RNNR regualator in Webench tool. Is there any way i can provide the custom enable threshold voltage(4.3V) in tool.

And from the data sheet page no.17 Equation 17, we can calculate the values of resistor divider for custom Vstart and Vstop. I need to know what are these Vstart and Vstop.

Please share you suggestions.

Regards,

Hareesh

  • 0
    Prodigy 210 points

    Hi All, 

    I got a simulation result with TPS54318RTER regulator with the following values.

    R1 = 133K

    R2 = 105K

    Through calculation i got to know the Vstart = 2,7V and Vstop = 2.2V. We are supplying 5V input.

    Does this mean that if the supply is 2.7V the IC will be enables and if it is 2.2V ic will be disabled?

  • 0 in reply to Hareesh Panakkal
    TI__Expert 7500 points

    Hi,

    We are looking into this. Will feedback to you soon.

    Thanks,

    Lishuang

  • 0 in reply to Hareesh Panakkal
    TI__Expert 5470 points

    Hi Hareesh,

    I think the webench tool doesn't have the function to simulate the EN on for this IC. You can use pspice transient model with pspice for TI tool to complete the simulation. The tool is free to request.

    For the second question. The EN voltage is divided from the input voltage. Vstart and Vstop corresponds to the ENrising and ENfalling respectively. With the equation (4) in datasheet, ignoring the current source, you can find Vstop=VENfalling*(R1+R2)/R2 and Vstart=VENrising*(R1+R2)/R2. That's more easy to understand. Here the current source inside IC is added in equation of datasheet to make the equation more accurate. But the impacts are small if you use several kohm resistors for the R1 and R2. The Vstop and Vstart just change about serval mV when the impacts of current sources inside IC aren't considered.

    So you can use the equation on datasheet to calculate an accurate R1/R2 for desired Vstart/Vstop. Or you can also use Vstop=VENfalling*(R1+R2)/R2 and Vstart=VENrising*(R1+R2)/R2 to calculate approximate R1/R2. Then you can check if it can meet your requirement with simulation.

    Thanks.

    Regards,

    Andrew