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Switch with Ultra Low power consumption - needed

Vikas Thukuntla75
Intellectual 520 points
Other Parts Discussed in Thread: TS5A3166

Hi,

I am designing a water meter product that runs on a battery. I have an external flow sensor that takes very less operating current (<1mA). Since this sensor is installed externally, I want to protect my electronics from external faults on this sensor. So, I am considering a Load switch with in-built protection features similar to TPS22943. However TPS22943 has very high Iq=40uA. Because of such high Iq, my battery will drain off faster. Can you suggest similar load switch that has in-built protection features like Over-current, etc and reports the fault? It will be better to have much more protections features than just over-current. I do not want to use any BGA packaged parts. Kindly suggest.

I have posted this in "Power Switches and Power Path Protection" forum. However they could not suggest any better IC with lesser Iq. They have suggested me the check for a suitable IC in this forum, and hence I am posting this here. Kindly suggest.

Regards,

Vikas Chandra Rao.

  • 0
    TI__Mastermind 45340 points

    Vikas,

    This is a common application request that we get for our signal switch products to be used in battery powered external sensors where supply current is a premium.  

    We do not have a signal switch today that has reports fault conditions or have over current protection but will be continuing to explore developing switches with those types of features as more people start to request them. 

    If you would like to see what we have a available today you can use the signal switch selection tool on TI.com.   Filter for 1:1, 1-channel switches, and sort on supply current least to greatest.  Since you are using in load switch application you may also want to filter on on-state resistance and continuous current that can pass through the I/O pin.  What do you think about the TS5A3166?   

    I imagine that that these protection features you are looking for will come at the cost of some current so I'm not sure what levels we will achieve as we develop these features.

    Thank you,

    Adam

  • 0 in reply to Adam Torma
    Intellectual 520 points

    Hi Adam,

    Thanks for your detailed reply. Since protection feature is a mandatory requirement, I will be unable to consider any of the above switches that you suggested looking for. It would be great if you can let me know once you start developing any suitable switch with protection feature.

    If not a integrated solution (like a single switch), can I get any required solution with more # of discretes/ICs? Can you suggest, if I should be checking in any other forum about suitable solution?

    Thanks & Regards,

    Vikas Chandra Rao.

  • 0 in reply to Vikas Thukuntla75
    TI__Mastermind 45340 points
    Vikas,

    I what type of faults are you trying to detect and what are you predicating that may cause those faults?

    I'm not sure exactly what level of robustness or protection you would like to achieve but the level of protection comes at a cost of current and I don't know where that sweet spot is for your system. Here are some ideas below.

    1) For example the ADG5243F device can detect a fault and communicate with a GPIO but it will consume >50uA of current to have this feature.

    2) The ADG4612 can detect a fault and open the switch. This is less power than the ADG5243 but it is still >50uA power consumption.

    3) You could place a clamp diode from your signal path to your supply to prevent an high voltage event from passing through your signal path.

    Maybe these ideas above can spark more ideas for you.

    Thank you,
    Adam
  • 0 in reply to Adam Torma
    Intellectual 520 points

    Hi Adam,

    Basically I want this protection feature for a water meter. I have the water flow sensor installed on the water pipe (sitting beneath the ground). There is a wire in between the flow sensor and the electronics. Flow sensor is powered through the electronics and sensor gives signals whenever there is water flow.

    Since flow sensor is installed under the ground and the wire is exposed to the ground conditions, they are susceptible to various kinds of noises/transients/lightning/etc. These can cause over-voltage, over-current, transients or any such faults. Hence I want to protect the electronics from these faults as much as possible.

    However the water meter runs on a battery, and its lifetime is important. Hence the power consumption of each and every part in the meter is crucial. Hope you have understood my criteria for selection.

    I will check and see what best possible protection device(s) I can have. However let me know, just in case you come across any suitable protection devices for my needs.

    Thanks & Regards,

    Vikas Chandra Rao.