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BQ24190: Schamatic and I2C Register configuration

Ema Sta
Prodigy 100 points
Part Number: BQ24190
Other Parts Discussed in Thread: BQ24192

Hi, 

We need to develop an application under android and will use bq24190 to charge 2 LiPo Batteries(parallel connection). We don't need usb detection, OTG and thermistor checking. We must just charge the batteries and send the information to android about the state of battery and visualize the info on the display with the fuel gauge. When we connect the usb cable to charge the batteries we want to turn on a red led. When the cable is disconnected the red led must be turn off.

Could anyone help us to set schematics and I2c register with correct values? thank you

This is the battery information:

  • 0
    TI__Mastermind 25800 points
    Hey Ema,

    For a reference schematic, I recommend looking at the application section of the BQ24190 datasheet as a starting point. You may also use the BQ24190EVM for reference.

    Because we do not have any details about input power constraints or system load information, this will be a bare minimum for you to get up and going.

    First, switch to the BQ24192 rather than the BQ24190 since you do not need input current detection.
    1) /PG pin is where you can connect your red LED.
    2) Pull PSEL pin low for max current limit.
    3) Pull OTG low.
    4) Set the TS pin with a resistor divider from REGN to GND such that VTS = 50-60%VREGN.
    5) Pull the ILIM pin to GND to ignore this pin and use the register set value.
    6) Short TS1 and TS2
    7) Tie /CE low to always enable charge.

    In the register bits:
    1) Minimum programmable charge current is 512mA. However, there is a bit to set 20% of this "Fast Charge Setting".
    2) Program REG02 - FORCE_20PCT bit, and set ICHG[5:0] to your 0.2C or 0.5C rates divided by 20%.

    Everything else is bells and whistles for your design.


    Regards,
    Joel H
  • 0 in reply to Joel Hernandez II
    Prodigy 100 points

    HI joel thank you for your support.

    We can't switch to bq24192 because we don't have the driver for android.

    We have to use bq24190.

    I'm just developing the schematics for bq24190. I iwll post here my design.

  • 0 in reply to Joel Hernandez II
    Prodigy 100 points

    So Joel, I developed this schematic for my application, please take a look

    If I remove R13 and R14, bq24190 will works normally or there will be strange behaviour ? 

    Thank you very much

  • 0 in reply to Ema Sta
    TI__Mastermind 25800 points
    Hey Ema,

    There are several things missing that would be required.

    1) The BAT pins require a 10uF decoupling capacitor to PGND.
    2) Since you cannot switch to the 192, it looks like you are driving the LED yourself and have some form of input detection. Is this correct?
    3) Please at least a 1uF capacitor to the VBUS pin.
    4) I see that +MAIN_VBUS has a note about 3.3V. If VBUS is that low, you will not charge the higher voltage battery. The buck converter will not operate.
    5) If you remove R13 and R14 the charger will fail the DCD step of the USB BC1.2 detection and set a 100mA input current limit on the charger. From here, you will need to change the input current limit manually through the registers to get a higher input current limit threshold.


    Regards,
    Joel H
  • 0 in reply to Joel Hernandez II
    Prodigy 100 points

    Dear joel thank you very muche for your support. I made the modifications...take a look at the new schematics. About your point:

    1) The BAT pins require a 10uF decoupling capacitor to PGND.  DONE
    2) Since you cannot switch to the 192, it looks like you are driving the LED yourself and have some form of input detection. Is this correct? 

    I DON'T HAVE ANY INPUT DETECION. I FOLLOWED THE BQ241980EVM SCHEMATICS TO CONNECT THE LED. AS YOU CAN SEE VSYS IS THE VOLTAGE OUTPUT OF SW PIN. AND I CONNECTED "LED" NET TO STAT PIN. IS IT RIGHT?


    3) Please at least a 1uF capacitor to the VBUS pin. DONE


    4) I see that +MAIN_VBUS has a note about 3.3V. If VBUS is that low, you will not charge the higher voltage battery. The buck converter will not operate. 

    SORRY MY TYPO. +MAIN_VBUS IS THE VOLTAGE FROM USB CONNECTOR , SO , 5VDC.


    5) If you remove R13 and R14 the charger will fail the DCD step of the USB BC1.2 detection and set a 100mA input current limit on the charger. From here, you will need to change the input current limit manually through the registers to get a higher input current limit threshold.

    OK. SO MY QUESTION IS: MAY I SET THE REGISTERS WHENEVER I WANT OR WHEN YOU CONNECT THE CABLE THE REGISTERS WILL BE RESET TO DEFAULT VALUES ? I HOPE THIS REQUEST IS CLEAR. 

    EXAMPLE:

    1) I remove R13 and R14.

    2) I CONNECT USB CABLE AND MY REGISTERS ARE SET TO ACCEPT MAXIMUM CURRENT.

    3) SO, NOW , BQ24190 DO NOT DETECT USB. MY REGISTERS ARE STILL SET TO "MY VALUES"( MAXIMUM CURRENT) OR THEY WILL BE RESET TO DEFAULT VALUES (100mA)?

  • 0 in reply to Joel Hernandez II
    Prodigy 100 points

    Hi Joel, 

    I'm still waiting for your support. 

    Thank you.

  • 0 in reply to Ema Sta
    TI__Mastermind 25800 points
    Hey Ema,

    Your schematic looks very improved.

    A couple of points to consider:
    PMID and VBUS see the same voltage, so consider making C63 also 16V rated to get a similar DC derating characteristic from that capacitor.

    Make sure the I2C bus has a pull-up resistor to some rail.


    As far as the D+/D- detection. If R13 and R14 are removed, every time the input is plugged in, you will have to reset the input current limit to the maximum value. The default 100mA current limit from floating D+/D- lines may also present an issue if you have an unsequenced (always-on) loads on VSYS. With too high of a load and a depleted battery, VSYS may never regulate. So just keep this in mind when you are attempting to reprogram the charger's current limit.


    Regards,
    Joel H
  • 0 in reply to Joel Hernandez II
    Prodigy 100 points

    Hi joel, thank you for your support.

    We looked at the bq24190 linux driver and it's compatible with bq24192. There are just a couple of different bits. We can adapt it.

    So we can't use bq24190 as you told me in the first post because we can't set the maximum current every time we plug in an input. So please take a look at our BQ24192 schematics.

    About C63 we will change with 16V rated voltage. Abut I2C we already have pull up resistor. About Vsys, is the voltage form battery. I correct it.

    About PG pin. I read on datasheet is active low and turn on the led when the battery as a good level. I need to turn on led when the power of battery is low. I have to put a not port on this pin ?

    I

    looking forward your kind reply

  • 0 in reply to Ema Sta
    TI__Mastermind 25800 points
    Hey Ema,

    The schematic looks good.

    In reference to the /PG pin. The datasheet description of this pin is to state whether the input power is good, not the battery power. You will need to achieve this some other way. /PG pulls low when the input source qualification (VBUS) has been met in accordance with the datasheet.


    Regards,
    Joel H
  • 0 in reply to Joel Hernandez II
    Prodigy 100 points

    Thank you for your support Joel.

    Last question: We decided to remove the led from PG and STAT pin  and use android to turn on the red led. May i leave PG and STAT pin floating?

    thank you again.

  • 0 in reply to Ema Sta
    Prodigy 100 points

    ABout the inductor on the VSYS. I need at least 2A as output current, Which inductor i have to connect? I read on datasheet BQ24192 can reach 4.5A output current.

    thank you very much

  • 0 in reply to Ema Sta
    TI__Mastermind 25800 points
    Hey Ema,

    Please refer to section 10.2.2.1 Inductor Selection in the datasheet for details on inductor selection.

    The critical parameter is inductor saturation current rating as well as DCR to optimize efficiency.


    Regards,
    Joel H
  • 0 in reply to Ema Sta
    TI__Mastermind 25800 points
    And yes, you may leave the PG and STAT pins floating. They are open-drain outputs.


    Regards,
    Joel H
  • 0 in reply to Joel Hernandez II
    Prodigy 100 points

    Can you confirm me abou t the max output current is 4.5A? thank you.

  • 0 in reply to Ema Sta
    TI__Mastermind 25800 points
    Hey Ema,

    Yes, the charger supports up to 4.5A of output current as you saw on the datasheet.

    Based on my previous reply, ensure that your select the inductor accordingly.


    Regards,
    Joel H
  • 0 in reply to Joel Hernandez II
    Prodigy 100 points

    Thank you joel. We will procede with PCB . I will follow the pcb guideline on datasheet. I will inform you about the progress on this thread in the future. Thank you again for your support.

    Keep in touch