How to isolate 3.7V li ion battery at deep discharge voltage automatically

Discussion in 'General Electronics Chat' started by mishra87, Feb 6, 2016.

  1. mishra87

    Thread Starter Member

    Jan 17, 2016
    170
    2
    Hello,

    I want to isolate battery input at its deep discharge voltage. I have 3.7V Li-Ion single cell battery and it's deep discharge voltage is 3V. I want to disconnect the load from battery automatically when does it reach at deep discharge to avoid over draining and increase the life cycle of battery.

    So could anyone recommend me any device like relay , switches or something else which full fill my requirement.

    Thanks in Advance !!
     
  2. Dr.killjoy

    Well-Known Member

    Apr 28, 2013
    1,190
    156
    Ebayvhas battery protection circuit for cheap..
     
  3. crutschow

    Expert

    Mar 14, 2008
    13,052
    3,244
    Basically you could use a comparator, such as an LM339 or LM393 controlling a logic-level type P-MOSFET as a switch in series with the battery output (source to battery and drain to load).
    You need to add some hysteresis to the comparator trip point so it doesn't turn back on as the battery voltages rises some when the load is removed.
     
  4. mishra87

    Thread Starter Member

    Jan 17, 2016
    170
    2
    Thanks for your response !!!

    By using comparator , resistor and switch drain the battery at lower voltage because it get path to folw the current.

    Is is possible to implement this by using max809 and a mosfet FDC653N. 3V threshold can be set by max809.
     
  5. crutschow

    Expert

    Mar 14, 2008
    13,052
    3,244
    I don't see how you could use the max809 by itself, which puts out a short reset pulse in response to the voltage.
    You could use it to trigger a latch to turn off the MOSFET.
    The FDC653N is an N-Channel MOSFET. You need a P-MOSFET for a high-side switch.
     
  6. mishra87

    Thread Starter Member

    Jan 17, 2016
    170
    2
    Could you recommend me and CMOS IC having low voltage detection circuit for 3V.

    I do not understand more about mosfet switching. So could you please explain me or guide me some link which enables me to understand.

    What should be basic criteria for selecting mosfet for High side or low side switching.

    What is basic criteria for selecting N Or P channel MOSFET.

    It's all stupid questions but makes really sense for me.

    Thanks
     
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