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Load Switch selection

Lucas Pucheta
Intellectual 300 points

Other Parts Discussed in Thread: TPS22968, TPS22960, TPS22944

  • Hello,

    My team and I are working on a clinical-grade patch to assist in the monitoring that is ramping up around the current COVID-19 pandemic. We saw TI makes load switches and we’re looking for a way to shut off pieces of circuitry from our two series zinc air batteries to save power. Are there any in particular you’d recommend we look at?

    Here are some of the parameters of the application:

  • How long will the device be on at one time? We want to achieve 7 days of active life for the patch
  • Input voltage range – The nominal battery voltage is 2.8V (2 series cells)
  • Maximum continuous current – Max current seen would be around ~40mA depending on the load we need to switch
  • Number of channels – looking for 2 channels to be supported
  • Shutdown current – As low as possible, battery life is critical
  • 0
    TI__Mastermind 32650 points

    Hi Lucas,

    Please refer to https://www.ti.com/power-management/power-switches/load-switches/products.html to view our load switch catalog.

    Using the filters, you are able to select 2 channel devices. I would suggest looking at TPS22960 or TPS22968. I think because of your load current and Iq/Isd requirements, TPS22960 could be a good fit.

    Thanks for choosing TI Power Switches in your designs. 

  • 0 in reply to Shreyas Dmello
    Intellectual 300 points

    Thanks for this part suggestion!

    For the load switch, the TPS22960 looks like a nice option being that it’s very small in size and has really low power characteristics. My two concerns is the 75us slew rate might be a little too long, if you had a faster slew rate option that would help it come up quicker for devices downstream from the load switch. Also, with our operating current being 50mA or lower depending on the load, the 500mA continuous current rated on the FET internal seems quite high, I’m concerned that we won’t have a current limit trip early enough in case of a short condition. I’d prefer to have that option for a specific trip point depending on the load current (100mA or less CL). I’m open to using two single load switches if the size is comparable to the dual load switch.

    Thanks again!

  • 0 in reply to Lucas Pucheta
    TI__Mastermind 32650 points

    Hi Lucas,

    TPS22960 is our lowest Isd, Iq offering. We do have load switches meant for lower current values but these come with a few integrated protection features which push up the Iq and Isd. If you are interested in these switches you can look at our TPS2294x offerings.

    TPS22944 is one such example.