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BQ24070: Ways to Cause a Fault

Matt Zenthoefer
Intellectual 550 points
Part Number: BQ24070

Hi - 

Are there any known ways to make the BQ24070 fault other than what is listed below?

1. Charge Suspend (AC power removed)

2. Timer fault (pre-charge or charge timers)

3. Temperature fault

Is it possible to make the charger fault in an unknown way? Examples?

  • 0
    Intellectual 550 points
    4 days, no response... Is anyone at TI going to answer this question?
  • 0
    TI__Intellectual 1980 points
    Hello

    Sorry for the late, Please clear your question. what's your issue? what's the test condition?
  • 0 in reply to Kerry Song
    Intellectual 550 points
    Well, things have changed a bit in the last 4 days, so I will actually re-frame my question.

    I think that we are having charge termination issues.

    I finally got some hard data from one of our devices that show there is a charge termination issue.

    The behavior that we see is that we have a Li-ion battery in the device that is low. Around 3.6V to 3.7V.

    The wall supply is connected to the device and fast charging begins. However, within 15 minutes the BQ24070 shows reports that charging is complete. The wall supply is removed and the battery voltage quickly drops back to 3.6-3.7ish volts. I saw this happen to a device twice.

    You may remember from a previous post that I was questioning a load we have in parallel to the battery and whether or not that can cause charging issues. I found the following app note that says parallel load currents can cause charge termination issues, but it doesn't mention anything about pre-mature charge terminations. Is it possible for parallel load currents to cause pre-mature charge terminations? Or is that unknown?

    App note: www.ti.com/.../slva166.pdf
  • 0 in reply to Matt Zenthoefer
    TI__Intellectual 1980 points

    Hello,

    It should be the voltage drop between BAT pin and battery cause this issue. What's you BAT pin voltage(the voltage neat the charger BAT pin) when you termination happens?

  • 0 in reply to Kerry Song
    Intellectual 550 points
    During a successful charge it is about 4.19V.

    However, I have no idea what the voltage is when we have our problem, since the problem is very intermittent (maybe occurs 1 out of every 750 charge cycles). Is there anything I can do to induce a problem like this to occur?
  • 0 in reply to Matt Zenthoefer
    TI__Intellectual 1980 points

    Hello,

    The charger's regulation voltage 4.2V is for OUT pin, so 4.19V terminate is normal for battery.

    You can decrease the termination current or decrease the resistance between OUT pin and battery to improve it. Also check the internal resistance of your battery, does it too large for some battery.