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BQ25180EVM: Bq25180EVM sys_mode01 problem

Part Number: BQ25180EVM
Other Parts Discussed in Thread: BQ25180

Hi,

I have a BQ25180EVM. I have a lot of problem with it.

Firstly, I cannot use this EVM in SYS_MODE - 01.

I connected my battery, it has 4.2 V.

I opened my Power Supply, it is in 5 V

I sent this comment, myI2C_write(SYS_REG, 0x44); with STM32 MCU.

I observed that Vsys decreased 4.2 from 5 V in my Oscilloscope.

When i close down the power supply, Vsys is also decreased 1.77 V.

Is it a wrong application? What should i do for powering Vsys from battery? 

  • Hi Mehmet,

    Welcome to E2E! Can you provide a register dump after you write 0x44 to the SYS_REG register? 

    When i close down the power supply, Vsys is also decreased 1.77 V.

    Do you perhaps have a load on the SYS pin on the EVM?

    Best Regards,

    Anthony Pham

  • Hi Anthony

    Thank you for your interest.

    After sent the command 0x44 to the SYS_REG, I read these registers. 

    STAT0                    0x01
    STAT1                    0x00
    FLAG0                   0x00
    VBAT_CTRL          0x46
    ICHG_CTRL          0x05
    CHARGECTRL0   0x2C
    CHARGECTRL1   0x56
    IC_CTRL               0x84
    TMR_ILIM             0x4D
    SHIP_RST            0x11
    SYS_REG             0x44
    TS_CONTROL      0x00
    MASK_ID              0xC0

    Also after close down the Vin, i cannot read these registers.

    And, yes there are a load on Load. Because EVM has a LDO and led. Should it not be??

  • Hi Mehmet,

    Thanks for the registers!

    And, yes there are a load on Load. Because EVM has a LDO and led. Should it not be??

    These should be fine, I don't expect there to be problems if this your only load.

    Would you be able to provide a waveform of the VIN, VSYS, and I2C lines when you remove the VIN? When you say you cannot read, are you reading a NACK? 

    Best Regards,

    Anthony Pham

  • Hi Anthony,

    I see that when there is a valid Vin, I2C works properly but when Vin is gone, i observe just device address and not respons in I2C SDA line at my oscilloscope.

    Actually, I think my EVM is broken. Because there are a lot of problems i see. Let me i say them and please confirm me it is normal or not.

    1. I powered Vbat as 4.2V and then powered Vin as 5V and then Vsys was 5V. Is it normal? Should it be 4.5V?

    2. I decreased voltage of Vbat 3.7V and I read STAT1 is  0x48, so Battery UVLO Status is active. Should be Vbat is below 3V?

    3. I powered Vbat as 4.2V, 36 mA  and then powered Vin as 5V then 36 mA current in IN and 13 mA current in BAT.  Vsys was 5V. Then I sent command myI2C_write(SYS_REG, 0x44) after that currents in IN and BAT dont chance but just voltage of Vsys decreased 4.2V as i said yesterday. Are these currents normal?

    4.Same scenario, I powered Vbat as 4.6V, 40 mA  and then powered Vin as 5V then 33 mA current in IN and 19 mA current in BAT.  Vsys was 5V. Then I sent command myI2C_write(SYS_REG, 0x44) after that currents in IN and BAT dont chance but just voltage of Vsys decreased 4.6V. I closed down the Vin and thank God Vsys has not gone, stayed 4.6V but BAT current increased 40 mA. Is it normal?

    I should confess that when i try to understand this EVM in beginning of my study, I connected my battery reverse(GND and Vbat) by mistake. Until i had figured out it, it stayed this stuation. i guess it was 1 minute. May the EVM be broken due to this mistake?

  • Hi Mehmet,

    I powered Vbat as 4.2V and then powered Vin as 5V and then Vsys was 5V. Is it normal? Should it be 4.5V?

    Correct, if you haven't changed the SYS voltage to be in pass through mode, you should see 4.5 V.

    I decreased voltage of Vbat 3.7V and I read STAT1 is  0x48, so Battery UVLO Status is active. Should be Vbat is below 3V?
    I powered Vbat as 4.2V, 36 mA  and then powered Vin as 5V then 36 mA current in IN and 13 mA current in BAT

    These current measurements and the VBAT tripping UVLO at 3.7 V I think definitely points to a problem IC. 

    May the EVM be broken due to this mistake?

    This is looking to be the case here. If you're able, I'd recommend replacing the IC to see if that clears everything up.

    Best Regards,

    Anthony Pham

  • Thanks a lot Anthony,

    I have one more question.

    My system will be work along 24 hours with 600 - 800 mAh lipo battery maybe less capasity. Max current i need while working is 200 mA for 10 seconds. It will work intermittent (5 minute in sleep, 10 second working on). So, do you recommend BQ25180 for this system?

  • HI Hehmet,

    This would definitely be a good use case for the BQ25180! 

    Best Regards,

    Anthony Pham