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Looking for a bidirectional constant current solution

Gert Vierman
Prodigy 30 points
Other Parts Discussed in Thread: TPS25221

I'm looking for some ideas on designing a cheap/compact method to limit the maximum charge and discharge current of a single battery cell.

Requirements are voltage approx 1.5 to 4.0 V, current limiting to 1A; on over current, do not shut off but limit max current to 1A.

I am in the process of designing this using two TPS25221 placed back to back, but I'm not sure if this part would be happy in a constant overcurrent situation because of the heat dissipation. I'd rather use a switching CC regulator for this.

Is there a single part that can perform this task bidirectional? If not, what part would be a good choice for switching current limitation, would a switching LED driver be a viable alternative?

Thank you,

  • 0
    TI__Mastermind 38910 points

    Hello Gert,

    To better assist you, what is your exact application?

    And are you absolutely limited to your specifications, such as the voltage range? I ask because the TPS25221's VIN (min) is 2.5V and not 1.5V.

    The TPS25221's price range is from $0.14 to $0.24/1ku. What is your max price range?

    BR,

    Seong

  • 0 in reply to Seong Kim
    Prodigy 30 points

    I'm not fully briefed on al requirements yet, but as far as I understand at this time, the application is limiting the charge and discharge current on a specific kind of battery or supercapacitor cell for safety reasons. The voltage range should ideally be 1.6V to 4.2V.

    Unfortunately I'm not informed about max price range yet, TPS25221 price is low enough, I guess there is room here.

  • 0 in reply to Gert Vierman
    TI__Mastermind 38910 points

    Hey Gert,

    I will look into this and get back to you.

    BR,

    Seong

  • 0 in reply to Gert Vierman
    TI__Mastermind 38910 points

    Gert,

    Other than the TPS25221, the closest I found to your VIN spec is the TPS250x where VIN (min) is 1.8V. Another one is the TPS22908, but the VIN (max) is 3.6V. These, however, are also not a single part solution. A bidirectional switch that may be of interest is the TPS206x.

    To answer your question regarding LED drivers in your initial post, our LED drivers' min voltage also does not begin from the 1V range.

    During my search, I found an interesting Application Note that covers implementing bidirectional control using eFuse devices. You can see the Application Note here. Although I found a few TI eFuse devices that meet your VIN spec, they are quite high in price.

    I will continue to look for other alternative solutions and will let you know.

    BR,

    Seong

  • 0 in reply to Seong Kim
    TI__Guru** 101701 points

    Hi,

    Two-chip solution should be possible. But the min operating voltage of our eFuses is 2.7V. Is that good enough for your need? Please let me know if you have any further questions.

    BR,

    Rakesh