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BQ25750: Does BQ25750 is completely standalone and doesn't need to be programmed or controlled by I2C?

Nasrin Enayatzadeh
Prodigy 40 points
Part Number: BQ25750
Other Parts Discussed in Thread: BQ24172, BQ24618

Hi support team,

My first question is, Does BQ25750 is completely standalone and doesn't need to be programmed or controlled by I2C?

My main design Description: I'm looking for a battery backup charger IC, preferably operating standalone with a thermistor feature.

my system input and output voltage is between 5-12V, and if the power source is disconnected, the IC can switch to the battery and power the load, it basically has the power path option.

Also using 1cell, 3.7V battery, so any IC that boost the battery voltage to 5-12V to support the load. I would appreciate introduce me any IC available with these requirements

Thanks in advance 

  • 0
    TI__Mastermind 21425 points

    Hello Nasrin,

    Thank you for reaching out. I'm reviewing your requirements, and checking which Battery IC would be best for your system.

    Do you know what charge current you will need?

    Do you know what the system load power requirements will be?

    In the mean time here is a link to a list of our battery charger IC's . 

    Best Regards,

    Christian.

  • 0 in reply to Christian Moyer
    Prodigy 40 points

    Hi Christian, 

    Thanks for your reply!

    Right now I don't have specific charge current, but it doesn't need to be fast

    the load requires 5-12V and will draw 3A. 

    Do you know if I can use BQ25750 completely standalone and won't need program through I2C?

  • 0 in reply to Nasrin Enayatzadeh
    TI__Mastermind 21425 points

    Hello Nasrin,

    Nasrin Enayatzadeh said:

    Right now I don't have specific charge current, but it doesn't need to be fast

    the load requires 5-12V and will draw 3A. 

    Thank you for this information.

    Nasrin Enayatzadeh said:
    Do you know if I can use BQ25750 completely standalone and won't need program through I2C?

    The BQ25750 can be controlled through I2C, or it can act as a completely standalone device.

    I'm going to review this information and will provide and update after I gather more information.

    Best Regards,

    Christian.

  • 0 in reply to Christian Moyer
    TI__Mastermind 21425 points

    Hello Nasrin,

    Nasrin Enayatzadeh said:
    I would appreciate introduce me any IC available with these requirements

    I recommend using BQ24172. This device is completely standalone, and it has the thermistor feature.

    Nasrin Enayatzadeh said:
    Also using 1cell, 3.7V battery, so any IC that boost the battery voltage to 5-12V to support the load. I would appreciate introduce me any IC available with these requirements

    We don't have any standalone battery charger IC that will boost the battery voltage to support system load. I recommend using BQ24172 and adding a seperate boost device to your system.

    Best Regards,

    Christian.

  • 0 in reply to Christian Moyer
    Prodigy 40 points

    Hi Christian,

    Thanks for recommendation.

    why do you suggest BQ24172 over BQ25750? I'm curios

    and when I read BQ25750 I though the IC itself will boost Battery voltage of (ex:3.7 V) to 5V, did I misunderstand the information? 

  • 0 in reply to Nasrin Enayatzadeh
    TI__Mastermind 21425 points

    Hello Nasrin,

    Nasrin Enayatzadeh said:
    why do you suggest BQ24172 over BQ25750? I'm curios

    The BQ25750 is more expensive then the BQ24712, and is designed for higer power applications. The BQ25750 will still work on low power systems, but  I wanted to suggest a device that would meet your required parameters at a lower cost. The BQ25750 supports standalone charging mode, but It will still need I2C communication to to operate in reverse mode.

    Nasrin Enayatzadeh said:
    and when I read BQ25750 I though the IC itself will boost Battery voltage of (ex:3.7 V) to 5V, did I misunderstand the information? 

    Yes, the BQ25750 is able to boost the battery voltage to support the system load, But the device will require I2C communication to work in reverse boost mode.

    Best Regards,

    Christian. 

  • 0 in reply to Christian Moyer
    Prodigy 40 points

    Hi Christina,

    the design requirements changed, I need an input voltage range +20V, would BQ24618 work?

    Also I have a design question, as I mentioned before I have 1 cell battery with 3.7V and I need 5-12V for system output. So I need to connect the + side of battery (3.7V) to Boost converter to get 5 or 12V, apply this voltage to pin22, BTST (BQ24618), is this topology correct?

  • 0 in reply to Nasrin Enayatzadeh
    TI__Mastermind 21425 points

    Hello Nasrin,

    Nasrin Enayatzadeh said:
    the design requirements changed, I need an input voltage range +20V, would BQ24618 work?

    Yes, BQ24618 should work.

    Nasrin Enayatzadeh said:
    Also I have a design question, as I mentioned before I have 1 cell battery with 3.7V and I need 5-12V for system output. So I need to connect the + side of battery (3.7V) to Boost converter to get 5 or 12V, apply this voltage to pin22, BTST (BQ24618), is this topology correct?

    Your design should be similar to the the one down below.

    Best Regards,

    Christian.

  • 0 in reply to Christian Moyer
    Prodigy 40 points

    Hi Christian,

    I appreciate your replying to my questions.

    I'm studying BQ24618 more; I want to make sure using one Cell, 3.7V battery is suitable for this IC. 

    In datasheet page 5, the device comparison table is 1-6 batter 4.2V/cell. Also at beginning of page 20, "If the BTST pin to PH pin voltage falls below 4.2 V for more than three cycles, then the high-side N-channel power MOSFET is turned off" 

    So when the battery is 3.7V the high-side N-channel power MOSFET is always be turned off. 

    Please let me know if 3.7V is okay to use or not

    In addition, because of project requirements, I'm going to use the boost converter on the system output instead of the V battery. So Vbattey is 3.7V and not boosted

    Thanks 

  • 0 in reply to Nasrin Enayatzadeh
    TI__Mastermind 21425 points

    Hello Nasrin,

    Nasrin Enayatzadeh said:
    I'm studying BQ24618 more; I want to make sure using one Cell, 3.7V battery is suitable for this IC. 

    Yes, BQ24618 should be able to support battery charge voltages between 2.1V-26V.

    Best Regards,

    Christian.