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Need 9V Li-Ion battery charger circuit

udhay kumar
Intellectual 295 points
Other Parts Discussed in Thread: BQ2057W

Hi Ti,

I'm looking for a good & fast charger for 9V rechargeable battery. The battery specifications are, 9V/900mah, Li-Ion. Please suggest a battery charger IC for my requirement.

Thanks & Regards

Udhay

  • 0
    TI__Guru**** 166696 points

    What is the input voltage and current available from your input source to the charger?

  • 0 in reply to Jeff F
    Intellectual 295 points

    Hi Jeff,

    Thanks for the reply. We required this battery charger for a "Fiber Optical Handheld Equipment". I don't have any idea or experience in designing a battery charger. I'm looking for a charger for battery like this one, http://www.aliexpress.com/item/2-pcs-lot-9v-SUPER-BIG-880mAh-li-ion-lithium-Rechargeable-9-Volt-Battery-Manufacturer-s/1177990444.html

    You can suggest a suitable voltage source & current rating for my requirement. I'm waiting for your replay.

  • 0 in reply to udhay kumar
    TI__Guru**** 166696 points

    The vast majority of LiIon chargers are step down (buck), meaning the input votlage needs to be higher than the max charge voltage.  A buck charger can be either  linear (usually < 1.5A) or more efficienct switching.  One low-cost linear option is the bq2057W linear controller, requiring an external pass FET.   I am bit confused by the "9V" as two LiIon batteries in series generally need only 8.4V to be fully charged. 

  • 0 in reply to Jeff F
    TI__Guru**** 166696 points

    Regardless, you will need an input voltage of at least 10V and no more than 12V if you use a linear charger.