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BQ24030 charge termination issue

Serge Sozonoff
Prodigy 70 points
Other Parts Discussed in Thread: BQ24030

Hello All,

I have designed a circuit around the bq24030 and for a reason I am unable to determine charging does not seem to terminate when it should.

I have gone over everything several times and don't see anything wrong.

I am using a bench supply as the AC power source set at 7V/500mAh (no USB present), R(set)value is 3.3KOhm which provides a charge current of roughly 320mAh and sets I(term) to 32mAh. Timers (TMR) are disabled by tieing TMR to LDO.

Using an Oscilloscope I measure Iset1 at 2.5V when charging a partially depleted cell and when charge current to the battery reaches ~32mAh I measure just below 250mV on Iset1 with a Lipo cell voltage just over 4.2V 

My understanding is that charge should terminate but Stat1 remains and charging seems to continue based on the fact that I see no noticeable differences and current just keeps tailing off.

Iset1 trace is short and goes directly to the Rset resistor which goes to ground.

Does anyone have any thoughts on this? What have I missed ?

Kind Thanks,

Serge

 

  • 0
    Prodigy 70 points

    Hi again,

     

    I just saw this in another post

    "Could you post your schematic and describe your test conditions?  There are several things that can disable the IC from declaring a termination.  If the TMR pin is tied to Vref, termination detection is disabled.  If the IC is in thermal regulation, termination detection is disabled."

    Am I to interpret this as tying TMR to Vref disables termination detection completely ?? My understanding was that it simply disables termination when the timer expires?

    Thanks,

    Serge