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BQ25121A: VIN_UV

Dima S
Prodigy 220 points
Part Number: BQ25121A

Hi

Working on BQ2521A.

I get a VIN_UV fault each time I stop charging the device.

Console: Faults and Faults Mask Register1 is: 0x4f, err:0x00

Masked it, but it keeps happening again although DATA sheet says it is cleared on read.

What is the UVLO event? is it happening all the time? how can I get reed of it?

From the Data Sheet:

VIN_UV R x 1 - VIN undervoltage fault. VIN_UV is set when the input falls
below VSLP. VIN_UV fault shows only one time. Once read,
VIN_UV clears until the the UVLO event occurs.

  • 0
    Prodigy 220 points
    Console: Faults and Faults Mask Register1 is: 0x4f, err:0x00
  • 0 in reply to Dima S
    TI__Genius 12485 points

    Hi Dima,

    How are you stopping the charging process? Are you disconnecting the adapter or are you actually using the /CD pin or I2C write to disable charging?

    Masking as with the other faults like BUVLO masks the interrupt from being sent. If the adapter was indeed disconnected, it will indicate a VIN_UV fault as the adapter voltage is low. 

    Regards,

    Gautham

  • 0 in reply to Gautham
    Prodigy 220 points

    HI

    First, we disconnect power that will issue a PMIC error - charging is still enabled (both CD pin and Register allow charging)

    But then, we close charging, both (both CD pin and Register disable charging).

    But error will not get cleared...PMIC does not enter ship mode with an error.

    Reading register after disconnect:

    01/01 00:06:37.020 Console: Status and Ship Mode Control Register0 is: 0xc7, err:0x00

    01/01 00:06:37.026 Console: Faults and Faults Mask Register1 is: 0x40, err:0x00

    01/01 00:06:37.033 Console: TS Control and Faults Masks Register2 is: 0x0f, err:0x00

    01/01 00:06:37.039 Console: Fast Charge Control Register3 is: 0xea, err:0x00

    01/01 00:06:37.045 Console: Termination/Pre-Charge and I2C Address Register4 is: 0x1a, err:0x00

    01/01 00:06:37.051 Console: Battery Voltage Control Register5 is: 0x64, err:0x00

    01/01 00:06:37.057 Console: SYS VOUT Control Register6 is: 0xfe, err:0x00

    01/01 00:06:37.063 Console: Load Switch and LDO Control Register7 is: 0xfc, err:0x00

    01/01 00:06:37.069 Console: Push Button Control Register8 is: 0x68, err:0x00

    01/01 00:06:37.075 Console: ILIM and Battery UVLO Control Register9 is: 0x3a, err:0x00

    01/01 00:06:37.081 Console: Voltage Based Battery Monitor RegisterA is: 0x6c, err:0x00

    01/01 00:06:37.087 Console: Status of VIN_DPM and Timers RegisterB is: 0x4a, err:0x00

    /CD pin is 1.

  • 0 in reply to Dima S
    TI__Genius 12485 points

    Dima,

    This is showing because of the adapter being unplugged. Can the FW be programmed to ignore this bit for your testing?

    regards,

    gautham

  • 0 in reply to Gautham
    Prodigy 220 points

    It can ignore, but this is not the issue.

    The system will not enter Ship mode when this error is displayed.

     

    I am not charging (charging disabled by pin and register),  and power is not connected (working on battery), so why does the error exist?

  • 0 in reply to Dima S
    TI__Genius 12485 points

    Dima,

    Could you clarify more on where the device doesn’t go to Ship Mode? Do you have a plot of the adapter going low, I2C command to enter Ship mode and /CD pin?

    VIN_UV indicates the adapter is not present which is what you are seeing.

    Regards,

    Gautham