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BQ25619: BATSNS functionality

Part Number: BQ25619

Hi,

We'd like to make use BATSNS pin and BATSNS_STAT bit to get the battery connection status, but found BATSNS_STAT is always read as '1' no matter a battery is connected to BATSNS pin or not.  Please help to clarify how can we make use of BATSNS_STAT bit to get the information we need.

Thanks!

Antony

  • Antony,

    If BATSNS pin is open or short to ground, BATSNS_STAT bit is set to 1 and charger regulates the battery voltage through BAT pin.

    Thanks,

    Ning.

  • Hi Ning,

    Sorry for the typo.  The customer told me that actually BATSNS_STAT bit is set to 0 always no matter a battery is connected to BATSNS or not.  Do you know what could be the reason?

    Thanks!

    Antony

  • HI Ning,

    Do you have any update about this?  Please share all related details about BATSNS_STAT bit and BATSNS behaviors.

    • Is there any other related registers or HW status that should be configured correctly to get the desired result from BATSNS_STAT?  (e.g. BATSNS_DIS bit?)
    • Is there any specific way to measure BATSNS pin to judge if BATSNS_STAT  should be '0' or '1'?

    Thanks

    Antony

  • Antony,

    Was BATSNS function tested on the customer board or on the BQ25619 EVM?

    Thanks,

    Ning.

  • Hi Ning,

    It's from customer board.  Do you have an EVM in hand to cross check on this?

    Thanks!

    Antony

  • Hi Antony:

    When BATSNS pin is not connected to BAT pin, BATSNS pin is open or short or connected to any other circuit? We will double check on our EVM.

    Regards,

    Hong

  • Hi Hong,

    After cross checking with customer, the test isactually performed on our EVM with VBUS/I2C connected to customer board so that they can read/write our register from the EC on customer board.

    On our EVM, it’s configured as below.

    • JP2 is open
    • J4 (both pin2 & pin3) is unconnected.
    • VBUS is supplied from customer board.

     Under above configuration, they told me reg0A is read as 0x90 for the first time, but it become 0x80 since the 2nd read and afterward. Do you have any idea what happens here?

    In parallel, if BATSNS is short to BAT but BAT is not connected to anywhere (no battery connected), what would the status of BATSNS_STAT bit when VBUS is valid?  Would there be a valid voltage on BAT under such situation so that BATSNS_STAT is  read as '0'?  

    Thanks!

    Antony

  • Hi Antony:

    Q1:  If BATSNS is short or open during startup, regulation will regulate on BAT after powerup. BATSNS detection occurs at powerup. For this case, is BAT pin connected to battery or not?

    Q2: In this case, BAT pin is sensed and regulated. Regarding BATSNS_STAT, will verify on bench and have you updated.

  • Hi Hong,

    For Q1, BAT pin is not connected to battery,  This pin is ununconnected.

    Antony

  • Hi Antony:

    I checked on bench and the BATSNS_STAT heaves as expected when VBUS is plugged in.

    Q1: Under above configuration, they told me reg0A is read as 0x90 for the first time, but it become 0x80 since the 2ndread and afterward. Do you have any idea what happens here?

    Yes, this is correct. BATSNS_STAT is treated as fault, 2nd read will clear the fault. So 0x90 becomes 0x80.

    Q2: In parallel, if BATSNS is short to BAT but BAT is not connected to anywhere (no battery connected), what would the status of BATSNS_STAT bit when VBUS is valid?  Would there be a valid voltage on BAT under such situation so that BATSNS_STAT is  read as '0'?

    BATSNS_STAT will be reported no matter BAT is connected to battery or not. With battery connected to BAT pin, the default REG00[5] is to detect BATSNS. If battery is connected to BAT pins, to indicate detection status, BATSNS_DIS needs to be 0 to detect BATSNS when VBUS is plugged in.   

    Regards,

    Hong

  • Hi Hong,

    Let me clarify your test result firstly.  Did you test on EVM for the two cases described as below and also get the result within the description as well?

    Case1: When VBUS is plugged in with both BAT and BATSNS pins are unconnected ( BATSNS_DIS=0), the first reading of BATSNS_STAT is '1', and the 2nd reading of BATSNS_STAT is still '1'.

    Case2: When VBUS is plugged in with BATSNS pin connected to a valid battery (BATSNS_DIS=0), the first reading of BATSNS_STAT is '1', and the 2nd reading of BATSNS_STAT is become  '0'.

    Additionally, some further questions.

    • Is BATSNS_DIS default value always '0' no matter there's a battery connected to BAT pin or not?
    • When BATSNS short to BAT pin but no battery connected to BAT, should we expect BATSNS bit read as '1' considering BATSNS_DIS=0?

    Antony

  • Antony:

    Please see my confirmation below:

    Case1: When VBUS is plugged in with both BAT and BATSNS pins are unconnected ( BATSNS_DIS=0), the first reading of BATSNS_STAT is '1', and the 2nd reading of BATSNS_STAT is still '1'.

    1. BATSNS_DIS = 0, BATSNS_STAT=0 before powerup

    2. After power up, first reading: BATSNS_DIS = 1 (means BATSNS detection is complete), BATSNS_STAT=1 (meaning BATSNS is open or short)

    3. After power up, second reading: BATSNS_DIS = 1; BATSNS_STAT=0 (meaning BATSNS fault is clear)

    Case2: When VBUS is plugged in with BATSNS pin connected to a valid battery (BATSNS_DIS=0), the first reading of BATSNS_STAT is '1', and the 2nd reading of BATSNS_STAT is become  '0'.

    1. BATSNS_DIS = 0, BATSNS_STAT=0 before powerup

    2. After power up, first reading: BATSNS_DIS = 0, BATSNS_STAT=0 (no fault)

    3. After power up, second reading: BATSNS_DIS = 0, BATSNS_STAT=0

    Additionally, some further questions.

    • Is BATSNS_DIS default value always '0' no matter there's a battery connected to BAT pin or not?
      • NO, there are different. With battery connected, BATSNS_DIS is programmable. If no battery connected, BATSNS_DIS = 0 by default.
      • BATSNS_DIS = 0 by default
      • If power up from VBUS without battery connected, default BATSNS_DIS = 0 will be chosen at power up
      • If there is battery connected to BAT pin. BATSNS can be programmed to either 0 or 1 by host, which means the BATSNS detection can be disabled by setting BATSNS_DIS = 1.
    • When BATSNS short to BAT pin but no battery connected to BAT, should we expect BATSNS bit read as '1' considering BATSNS_DIS=0?
      • No, the reading will be "0" because there is no BATSNS fault. BATSNS_STAT=1 (first reading) have 2 conditions: 1. BATSNS_DIS=0. 2. BATSNS pin is open or short.

  • Hi Hong,

    Thanks for your comments.

    If I understood correctly, the reading of BATSNS_STAT is always '0' (for either first or second reading) for two application scenarios listed below.

      • When VBUS is plugged in with BATSNS pin short to BAT pin connected to a valid battery (with BATSNS_DIS=0)
      • When VBUS is plugged with BATSNS short to BAT pin but no battery connected to BAT

    If that's true, how can we know if there's a battery connected or not?

    Thanks!

     

    Antony

  • Antony,

    We will get back to you on the next business day.

    Thanks,

    Ning.

  • Hi Antony:

    BATSNS_STAT is to report if BATSNS pin is connected to battery or not. The device has no battery present detection.

    Regards,

    Hong

  • Hi Hong,

    Do you mean the purpose of BATSNS_STAT bit is to report if BATSNS pin is connected to BAT pin or not?  And, there's no way from this chip to detect if there's a battery is present or not?

    Thanks!

    Antony

  • Antony:

    Yes, correct.