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[bq24230] Question about floating current when charging with dynamo

Hwang Gi-Sik
Prodigy 20 points
Other Parts Discussed in Thread: BQ24230

Hi ~

I actually haven't decided the chip yet. but, I mentioned part number in title because I read the notice of this forum. Sorry about that.

by the way, I am making Bicycle Solution that help cyclists charge their smartphone during riding and know where their bicycle is if they are stolen theirs using GPS and WCDMA modem with SHIMANO's hub-dynamo and Li-ion battery.

Anyway, I'm finding a charging IC that can charge the internal battery and ,at the same time, power to load (AVR, led, etc.). this may solve with dynamic power management function.

Assume that I use bq24230 and set the fast charging current and input current limit to 500mA.

The problem is whether the IC using CC/CV method can rightly charge when the output current of hub-dynamo is under the limits in CC fast charge mode.

Is there any problem? because the hub-dynamo can produce current about 200~300mA at low speed as the maximum current is 500mA.

I will appreciate your attention on this matter.

  • 0
    TI__Expert 7730 points

    Hello, Gi-Sik,

    If I understand you correctly, here's the answer to your question:

    In CC mode, the chip will try to charge at the constant current that you programmed. If your input (in this case is the hub-dynamo) can provide enough power, you will be able to charge at 500mA constantly. However, at the low speed where the input current is only 200-300mA, the charge current will be limited to the input power and is possible to charge at less than 500mA.

    Thanks,

    Wenjia

  • 0 in reply to Wenjia Liu
    Prodigy 20 points

    Hello, Wenjia,

    Thank you for your reply! 

    Yes, You understand correctly. And thanks to you,  All of my concern about charging IC is solved.

     Again thank you for your attention and have nice day!