MP2667 NTC Calculation

Battery Management
1

Hi,
I’m looking for help calculating both Resistors for the Thermal Regulation of the MP2667.
Are Vcold and Vhot voltage values or are they percentages?

I can’t even recreate the calculation with the given example values. Can someone give me an example?

My NTC Values are Rntccold:300K, Rntchot:20K (for ~0°C to 60°C)

Thanks.

ntc
ntc988×1219 144 KB

2

Hello, welcome to the MPS forums!

To answer your questions directly and in order:

  1. Yes, Vhot and Vcold and percentages of Vin. The following images are on page 9 of the
    MP2667 datasheet.

    image
    image1019×46 10.4 KB

    image
    image1013×48 10.4 KB

  2. From the datasheet, we can see that typically Vcold = 0.66x(Vin) & Vhot = 0.35x(Vin).
    In this example, let us say that Vin = 5V, Vcold = 3.3V, Vhot = 1.75V
    You mentioned that Rnt_Cold = 300kOhms & Rnt_Hot = 20kOhms
    Now it’s just a matter of calculating Rt1 & Rt2 using equations (1) and (2):
    image

Best,
Krishan

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