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LM334: Charging supercap and limiting voltage to 3,6V

Part Number: LM334
Other Parts Discussed in Thread: TLA431

Tool/software:

Hello All,

I'm building a gang charger station for supercaps (HLC). The current is limited to 5mA with an LM334.

I had to limit the final charging voltage to 3,6V. Using a clamping zener is not a perfect solution as it starts sinking current below 3,6V already -> slows down the charging.

Any single component can be used to clamp the voltage at 3,6V but with steeper breakdown slope?

Thanks,

Bálint

  • Hi Bálint,

    Thanks for your question!

    I'm not sure if I understand your question correctly. 

    My understanding is that you are looking for a 3.6V voltage reference. Is the 5mA limit from the LM334 on the same rail as the 3.6V?

    Additionally, does the LM334 circuit schematic look like the example below?

    Best Regards,

    Andrew Li

  • Hi Andrew,

    Yes, you understand right. The LM334 is in the below application, a simple current source.

    A reference shunt would be a good and simple solution. But so far I did not found one with fix 3,6V voltage. Would be nice to solve it with a single component. (need to rework the already produced modules)

    Thanks,

    Bálint

  • Hi Bálint,

    Thanks for the clarification!

    Unfortunately we do not have a 3.6V shunt voltage reference in our portfolio, but we do have adjustable shunts such as the TLA431 which can be configured with a few extra resistors. Can this fit your application?

    https://www.ti.com/product/TLA431

    Best Regards,

    Andrew Li