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TL432: Question regarding TL432 as shunt regulator

Wei-Hao Chen (TW-FAE)
Expert 3260 points
Part Number: TL432
Other Parts Discussed in Thread: TL431, TL431LI

Hi support team,

My customer wants to know how to calculate the maximum output current (to the load) for the TL432 based regulator circuit as the datasheet Figure 27 illustrated. 

Also, how does temperature affect the output current capability? 

 

  • 0
    TI__Mastermind 19550 points
    Hi Wei-Hao,

    The maximum current to the load is based on the Vo and Vsup.
    Itotal = (Vo -Vsup)/Rsup = Iload + Iq

    Iload = (Vo - Vsup)/Rsup -Iq

    Vo = Vref * (1 + r1/R2)

    Keep in mind that the TL431 will sink all the current unless the load is using it.
    If you require less than 15mA, I would highly use the TL431LI as it is a higher performance alternative.
    www.ti.com/.../TL431LI

    Temperature changes causes a temperature drift to occur on the TL431. This drift will appear on the Vo but it is very small 34mV vs 2.5V.

    -Marcoo