AS358 Lithium charger circuit

Discussion in 'General Electronics Chat' started by eyesee, Sep 6, 2014.

  1. eyesee

    Thread Starter Member

    Oct 19, 2013
    33
    3
    I have a commercial Lithium charger which uses a dual AS358M Op-Amp IC and is based on the circuit below. I am trying to understand how the charger functions and also how to adjust the charge rate?

    upload_2014-9-6_18-48-6.png
     
    Last edited: Sep 6, 2014
  2. ian field

    Distinguished Member

    Oct 27, 2012
    4,413
    782
    You might be better off not messing with a lithium charger unless you *REALLY* know what you're doing!

    If you overcharge a lithium cell, it can vent with flaming gas - There has been a spate of serious house fires in the UK, mostly because of cheapskates jumping on the E-cigarette bandwagon and designing dodgy lithium chargers with no end of charge shut off!
     
  3. eyesee

    Thread Starter Member

    Oct 19, 2013
    33
    3
    I am familiar with the CC/CV charge termination method that most Lithium chargers use. I am just curious how the above circuit works as I have seen similar designs used in other commercial chargers. I presume one of the resistors will set the CC charge rate but not sure which one?
     
  4. bertus

    Administrator

    Apr 5, 2008
    15,645
    2,344
    Hello,

    None of the values is given in your drawing.
    Also nothing is mentioned about the SMPS block.
    At R2 it says current sensing.

    Bertus
     
  5. eyesee

    Thread Starter Member

    Oct 19, 2013
    33
    3
    The circuit is taken from a datasheet for the AS358 IC - it is a suggested design. I will try and measure exact component values and map out the circuit of the charger I have.
     
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