• State
  • Locked Locked
  • Replies 5 replies
  • Subscribers 63 subscribers
  • Views 160 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

BQ25890: OTG_CONFIG disables itself automatically

Alejandro Cabrerizo
Prodigy 70 points
Part Number: BQ25890

Hello,

We have been testing a design with the BQ25890 and charging and other features work as expected.

But when trying to enable its OTG functionality, the OTG_CONFIG register bit resets back to 0 by itself around 250ms after setting it to 1.

This only happens when the OTG pin is set high.

All the other conditions to enter boost mode seem fine and no faults are detected.

Register dump just after setting the OTG_CONFIG bit to 1:

Register value at 0x0: 0x48
Register value at 0x1: 0x6
Register value at 0x2: 0x5d
Register value at 0x3: 0x3a
Register value at 0x4: 0x20
Register value at 0x5: 0x13
Register value at 0x6: 0x5e
Register value at 0x7: 0x8d
Register value at 0x8: 0x3
Register value at 0x9: 0x44
Register value at 0xa: 0x73
Register value at 0xb: 0x2
Register value at 0xc: 0x0
Register value at 0xd: 0x12
Register value at 0xe: 0x4f
Register value at 0xf: 0x50
Register value at 0x10: 0x3f
Register value at 0x11: 0x0
Register value at 0x12: 0x0
Register value at 0x13: 0x8
Register value at 0x14: 0x1d

Register dump after 250ms:

Register value at 0x0: 0x48
Register value at 0x1: 0x6
Register value at 0x2: 0x5d
Register value at 0x3: 0x1a
Register value at 0x4: 0x20
Register value at 0x5: 0x13
Register value at 0x6: 0x5e
Register value at 0x7: 0x8d
Register value at 0x8: 0x3
Register value at 0x9: 0x44
Register value at 0xa: 0x73
Register value at 0xb: 0x2
Register value at 0xc: 0x0
Register value at 0xd: 0x12
Register value at 0xe: 0x4f
Register value at 0xf: 0x50
Register value at 0x10: 0x3f
Register value at 0x11: 0x0
Register value at 0x12: 0x0
Register value at 0x13: 0x8
Register value at 0x14: 0x1d

As you can see, the OTG_CONFIG bit went back to 0 with no faults.

Do you know why is this happening?

Thank you

  • 0
    TI__Mastermind 46671 points

    Hi,

    The charger did not enter OTG mode. Please check

    1) If all the boost mode conditions listed in 9.2.5 Boost Mode Operation from Battery on the d/s are met.

    2) Why VSYS (REG0F)=3.904V is higher than VBAT (REG0E)=3.884. When the battery is discharging, VSYS should not be greater than VBAT.

    Thanks,

    Ning.

  • 0 in reply to Ning T
    Prodigy 70 points

    1) Checking conditions:

    • Vbat is 3.884V according to the register 0x0E. Good
    • Vbus < Vbat + Vsleep. According to register 0x11, Vbus is 2.6V (0V). Good
    • The OTG_CONFIG value can be seen set in the register 0x03, and the OTG pin is high. Good
    • The TS hot value is set to 37.5% and the cold to 77% according to reg 0x01. The current value is 50%, according to register 0x10. Good

    2) That is strange. I collected more register data and now they are both at the same voltage:

    Register value at 0xe: 0x49
    Register value at 0xf: 0x49

    The device draws very little power from the battery (10-20mA) and that might be why both voltages are roughly the same

  • 0 in reply to Alejandro Cabrerizo
    TI__Mastermind 46671 points

    Hi,

    Do you have any load connected to SYS or VBUS or PMID pins?

    Thanks,

    Ning.

  • 0 in reply to Ning T
    Prodigy 70 points

    Hello,

    No load was connected to VBUS.

    The PMID pin is connected to a 10uF capacitor to ground as the dataseet reccommends.

    There is a load connected to the SYS pin (The usual system load) of around 50mA.

    Thanks for your time,

    Alejandro

  • 0 in reply to Alejandro Cabrerizo
    TI__Mastermind 46671 points

    Alejandro,

    1. Is there OTG output (~5V) at PMID pin right after setting the OTG_CONFIG bit to 1?

    2. Do you use real battery or battery simulator at VBAT?

    Thanks,

    Ning.