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Litihium-Ion Charging Circuit Help Needed

  1. Feb 5, 2013 #1
    Hello everyone! First post, so I apologize if I am in the wrong area.

    I am designing a charging circuit for a project, but I don't have much experience with power electronics. The circuit must output 3.3V and be rechargeable through the use of a USB power supply (5V DC). Here is what I am currently thinking:

    I'm looking into an LM3622M-8.2 lithium-ion charge controller, an eForCity 2000 mAh battery, and a TPS54316 voltage regulator.

    My current plan is to have the voltage from the USB going straight into the LM3622, which will regulate the voltage and current being applied to the battery. It looks like the LM3622 will do most of the regulation for me, but I was wondering what else I might need to do. The battery will push 3.7V to the TPS54316, which is step down the voltage to 3.3V before it is sent to the rest of the circuit.

    So my main questions are:
    - What do I need to do with the LM3622?
    - Is there a better component for lithium-ion voltage regulation?
    - Is there a better way to design a lithium-ion charging circuit?
    - Am I missing something big?
    - Does this seem like it will work?
  2. jcsd
  3. Feb 6, 2013 #2

    Just a quick word. Best of luck with your project.
    I hope I don't have to tell you that Lithium-Ion batteries can be unforgiving if not downright dangerous if charged incorrectly.

  4. Feb 6, 2013 #3


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    I'd second that advice. If you stick to what the application sheet for that controller tells you then you should be OK. They will certainly tell you about any obvious dangers involved with charging Li batteries.
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