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Temperature sensor to control cooling fans

nkvillai
Prodigy 20 points
Other Parts Discussed in Thread: OPA333, ADS1014, ADS1114, OPA364, OPA348

Hi,

I'm looking for an IC that will allow me to use the existing OEM temperature sensor on an automobile. The OEM sensor is a thermistor. I'm looking for an IC that will allow me to measure the voltage from the OEM sensor without feedback (I do not want the measurement to effect the regular voltage so as to keep the ECM happy).

Is there any chip out there that will allow me to do this?

Thanks

  • 0
    TI__Expert 7185 points

    You can buffer the thermistor with a single supply OPA such as an OPA348, OPA333, OPA364, etc. depending on your cost, accuracy, and power needs.  You can interface the buffered thermistor voltage directly to a spare A/D on a uC.  If not, some good low power A/D converters to consider would be the ADS1014/5 or the ADS1114/5. 

    -Matt

  • 0 in reply to Matthew Hann
    Prodigy 20 points

    Couldn't I use the OPA to buffer the thermistor then use a voltage comparator?

     

     

  • 0 in reply to nkvillai
    TI__Expert 7185 points

    Of course--if all you want to do is use the output level from the thermistor to control a fan (without any signal processing), this would be fine.  However, if you are interfacing directly with a comparator, you most likely will not need the OPA buffer and can tie the output of the thermistor directly to the input of the comparator.