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TPS3780-Q1: TPS3780-Q1 Sense Pin Resistor Divider

Sam Shah
Prodigy 65 points
Part Number: TPS3780-Q1
Other Parts Discussed in Thread: TPS3808

Hello,

I am planning to use TPS3780-Q1 in my design. I have calculated voltage divider resistor values using app note SLVA450B. The resistor numbers are coming out to be in Mohm range. These numbers seem too large and I fear that noise coupling could happen through the large value resistors. I assume that the calculation used 100x large current  on the voltage divider than I_sense pin current in order to reduce loading on the voltage rail. Could the current be 1000x or 10000x larger in case loading on the voltage rail is not a concern?

Thanks,

Sam

  • +1
    TI__Genius 10951 points

    Hi Sam 

    • Figure 3-1 in The app note SLVA450 explains that the system accuracy will increase when the resistor decreases, i.e. when you are ready to burn more current in the resistor ladder.  You can decrease the value of resistors as per your loading budget.  
    • Just a caution , please make sure that you are not using the same threshold limits as mentioned in SLVA450B app note as they have explained TPS3808 in their design example. 

    Good luck with your design. 

    Regards

    Trailokya