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bq25890 / Question about D+/D- detection

S.Satoshi
Guru 21675 points
Other Parts Discussed in Thread: BQ25890, BQ24190, BQ25890H

Hi Everyone,

Please let me ask D+/D- detection of bq25890.

  1. Can we know that the D+/D- detection is completed via output of any pins or bit in resister? Our customer need to know it for both auto detection at USB connector connected and force D+/D- detection.
  2. Please let me know the required time to complete D+/D- detection. Our customer just want to know what time they need to wait in the worst case.  Before I asked the same question for bq24190 then I had comment as below.

Best Regards,

Sonoki / Japan Disty

  • 0
    TI__Intellectual 1910 points

    1.The D+/D- completion triggered by auto detection is indicated by the third INT pulse after adapter plug-in and VBUS_STAT is updated. The FORCE_DPDM bit is set while force detection is in progress. Similarly, the VBUS_STAT is updated after completion

    2 The completion time depends on the input source. I will send you the timing offline due to confidentiality required.

     

     

  • 0 in reply to SamW2000
    Intellectual 285 points

    Hi,

    I have a aquesyion regarding the input D+ D- detection of the BQ25890. Does the detection happen only when an input is plugged in or can it be forced by software?  The reason I ask is the detection gives a different response when adapter is plugged in to charge a deeply charged battery.

  • 0 in reply to Ganesan Manikandan7
    TI__Mastermind 25800 points

    Hey Ganesan,

    The bq25890 will perform detection when an input is plugged in, and if in host most, a register reset (either by REG14[7] or a Watchdog Timer Expiration).

    Now when you say it gives a different response when the adapter is plugged in to a deep discharged battery, can you please elaborate on what it is detecting in both conditions (i.e. battery normal and battery deeply discharged)?

    Regards,

    Joel H

  • 0 in reply to Joel Hernandez II
    Intellectual 285 points

    Hey Joel H, thanks for getting back to me on that. To give you clarity on what's happening, I have attached a scope screenshot as well. When the system is up and running, and I plug in the adapter, the MaxCharge handshake occurs and I see 9V/12V at the input of the charger IC (VBUS). This is good because I can then set the input current to be maximum (3.25A) and also modify a few other registers (like IR compensation and watchdog timer disabling etc) so I can charge with a constant current of 3.5A. All is well and good. On the other hand, when the battery voltage drops below 3.0V (the PCM inside the battery trips) the system doesn't boot because of insufficient voltage. In this case, when I plug in the charger, the system begins to boot (per the design) and the battery also begins to charge, however I see only 5V at the input of the charger IC and consequently charging with meager current (<3A). I waited for quite a while for the battery voltage to rise but still the charger IC doesn't wanna switch to the 9V/12V and pump the charge current up. A quick fix is to unplug and re plug the charger cable and it works like magic.  Can you see why this is happening?

    Each time the D+/D- detection happens, I read VBUS[STAT]=100: Adjustable High Voltage DCP (MaxCharge) (1.5A) following which I set the input current limit manually through the host and disregard the ILIM pin.

    Note: I am using a Qualcomm Quick Charge (3.0) adapter and the charger is always operated in the host mode.

    Thanks in advance!

    Ganesan

    BQ25890_VBUS.pdf

  • 0 in reply to Ganesan Manikandan7
    TI__Mastermind 25800 points

    Hey Ganesan,

    I am including a link to Fernando's reply to a similar post here.

    It includes a brief description of what I believe you are seeing (an input current limit to 1.5A) and a link to an app note that describes using the bq25890H to emulate the handshaking for the QC3.0 type charger.

    Let me know if this helps.

    Regards,

    Joel H

  • 0 in reply to Joel Hernandez II
    Intellectual 285 points
    Hey Joel, thanks for that info. I will look into the BQ25890H as well. I have another quick question. I understand the charger operates in 1.Default mode 2.Host mode Is it possible to change the default values of the parameters in the Default mode? Thanks Ganesan
  • 0 in reply to Ganesan Manikandan7
    TI__Mastermind 25800 points

    Hey Ganesan,

    Unfortunately, you cannot change the default values of these registers in Default Mode. These are set by design, and remain the reset values when there is a register reset condition.

    Regards,

    Joel H