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TINA/Spice/BQ2002: Detect if conenected battery is rechargeable

user5125090
Prodigy 40 points
Part Number: BQ2002
Other Parts Discussed in Thread: TINA-TI,

Tool/software: TINA-TI or Spice Models

The device I am building can be powered by USB or 3xAAA batteries. While connected to the USB, the device will charge the batteries. But before charging the batteries, the device needs to make sure the batteries are rechargeable.

I've made a circuit using BQ2002 to charge the batteries. If the batteries are not rechargeable, this circuit should not attempt to charge the battery (set charge control on BQ2002 to low).

How can I make sure my circuit doesn't try to charge every connected battery? Is there a IC that has this functionality?

  • 0
    TI__Mastermind 21590 points

    Hi,

    To do this, you'll have to use an MCU. Since NIMH has the lowest impedance of all AA batteries, you can calculate the impedance. The Impedance = RBAT = (VBAT(CLOSED)  –  VBAT(OPEN)) / IBAT(CLOSED) . VBAT(OPEN)is the battery voltage when no current is applied to the battery. VBAT(CLOSED) is when you apply a small current to the battery (<150mA). You can use this to get the battery impedance and determine if its a chemistry you want to charge or not.

    Regards,

    Raheem

  • 0 in reply to Raheem
    Prodigy 40 points
    Tanks for your reply,I'll try it right now.