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Original question:

TPS24750: May we know how to set up TPS24750 current in 5A?

TPS24750: IMON output to ADC formulas

William Sung36
Intellectual 395 points
Part Number: TPS24750

Hi,

I would like to connect the Imon output on the TPS24750 to a ADC input of a microcontroller so that i can monitor the system current consumption. There is not much details on how to do this or specific equations on the datasheet related to this. Can I assume that the current flowing through Rset is going to be equal to the current that will be flowing through Rimon? If this is the case and i assume that the max current flowing though Rset at my set current limit is 0.5mA, then can i scale the output accordingly? 

For example, Ioutmax = 360mA will give Current at Rset = 0.5mA, then when Iout = 180mA then current at Rset = 0.25mA?

Thanks

  • 0
    Intellectual 395 points
    Also forgot to ask, do i need to add a buffer on the output of Imon before going into the uC?
  • 0 in reply to William Sung36
    TI__Guru** 105361 points
    Hi William,

    You are correct on the statement.. Ioutmax = 360mA will give Current at Rset = 0.5mA, then when Iout = 180mA then current at Rset = 0.25mA.

    Other way to estimate load current is... Load current = Vimon * IMONsf
    Where Vimon is the voltage across the Rimon resistor and
    the current monitor scale factor is IMONsf = Rset/(Rimon*Rsense)

    Note, the max. voltage at IMON pin is limited to 675mV (typ), which is the Circuit breaker threshold value. Also, do not add any additional cap at IMON pin for filtering. I do not think a buffer is needed as ADC inputs are generally high impedance.

    Best Regards,
    Rakesh