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BQ24030: Questions on Operation

Sarah Cratem
Intellectual 805 points
Part Number: BQ24030

Hello!

I have a few questions on the BQ24030RHLR:

  1. If AC > 6V, VOUT is regulated to 6V. I don’t see a description of this. I take it, it is just PWMed so the average voltage = 6V (i.e. id AC=12V, Vout would be a 50% duty cycle, 12V peak). Is this the case?
  2. If the AC is connected and the charge is complete, this draws <5uA, and the battery is disconnected (AC driving board/OUT). If the AC and USB are disconnected, VBAT is connected to OUT (Q2) and the charger takes <5uA. Right?
  3. This is 1.5A max charge current, right? Is there a similar chip with 2A or 2.5A charge current?

Thank you!

Sarah

  • 0
    TI__Mastermind 22600 points

    Hi Sarah,

    1) The BQ24030 is a linear topology battery charger. When the AC adapter input supply is > 6V Vout is regulated to 6V via an internal linear regulator.

    2) When both AC and USB inputs are disconnected the device is in low power sleep mode. The current the charger draws will be a typical value of 2 uA and a max of 5 uA.

    3) Yes, the max charge current for this device is 1.5 A. Due to the DPPM feature the device can support up to 2 A total current draw between the system load and battery. In terms of linear charger chips there is not an option with similar features for 2-2.5 A charge current. I would recommend considering a switch mode charger for a 2-2.5A charge current requirement. 

    Refer to our Battery Chargers products page for a full list of devices that meet your specifications. https://www.ti.com/power-management/battery-management/charger-ics/products.html 

    Best Regards,

    Garrett 

  • 0 in reply to Garrett Kreger
    TI__Intellectual 805 points

    Hi Garrett,

    Very helpful, thanks! I have a couple follow-ups for you:

    Is the Vout linear regulator thermally protected? For example, if AC = 18V for extended periods and we drew say 50mA, that would be 0.6W which could heat up if it was sustained for a long time.

    Would Vout just turn off? Would it turn off current from AC and just connect battery to VOUT?

    Thanks,

    Sarah

  • 0 in reply to Sarah Cratem
    TI__Mastermind 22600 points

    Hi Sarah, 

    Yes, the device is thermally protected during charging. As you pointed out if Vin-Vout is large power dissipation will cause the device to heat up. If power dissipation results in a device junction temperature greater than 125°C  thermal regulation occurs and the device automatically reduces the charge current to lower the internal temperature. If the junction temperature rises to the thermal shutdown threshold of 155°C the AC and USB inputs are disconnected from the output and the battery is connected to provide power to the output terminal.

    Regards,

    Garrett

  • 0 in reply to Garrett Kreger
    TI__Intellectual 805 points

    Hi Garrett,

    Thank you!

    For signals like PSEL and CE that need to be high (for AC in) but can’t go above 7V, can I just put pull-ups to VOUT?

    Best,

    Sarah

  • +1 in reply to Sarah Cratem
    TI__Mastermind 22600 points

    Hi Sarah, 

    No you should not just connect those inputs with pull ups to Vout because the CE pin needs to be high to enable power to the Out pin, if CE is designed to be pulled high by the output the charge enable pin will always read low and the device will always remain in standby. How you connect your PSEL input is less critical because neither the low nor high state prevent operation. 

    Regards,

    Garrett