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Temp Sensor Shutodown/Memory

Geovid Kali
Intellectual 1245 points
Other Parts Discussed in Thread: TMP431, DXP

Hi,

I want to use a temperature sensor to monitor the temperature of my system and if it goes above a certain threshold to turn the system off.  I found a few digital sensors that have this functionality by using an ALARM interrupt.  Using this interupt I should have no problem implementing the shutdown.  My issue is on the auto restart.  I want system to restart when it is cool enough but in order to check the temperature my MCU has to be on.  I am worried that my MCU will restart when be damaged if the system is still too hot.  Is there a way I can check the temp before the restart?

The part I have been looking at is the TMP431.   

Thanks for the help,

Geovid Kali

  • 0
    TI__Mastermind 25130 points

    Geovid,

    Usually the DXP and DXN lines of the TMP431 are connected to an internal diode provided by the MCU. This is the best way to detect the temperature of the MCU. Even if the MCU is powered of this is ok. The TMP431 forces current through the internal diode and detects the temperature.

    That being said you do have another option. My suggestion would be to lay out your board such that the TMP431 is close to the MCU. In this way you will be measuring as closely as possible with the local temperature sensor in the TMP431. The Alert pin on the TMP431 will trip if either the remote or the local temperature cross the specified limits. It sounds like you are concerned with the approximate temperature (witihin a few degrees) in order to protect the system. You can acheive this with the local temperature readout.

    In either solution the temperature can be monitored before powering the system back on. My recomendation is to use the interenal diode of the MCU if possible.