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TL432A-Q1: TL432A-Q1 Application Problem

Fery Feng
Intellectual 2270 points

Part Number: TL432A-Q1

Hi team,

We got below 2 questions regarding to TL432A-Q1, could you please help to check about it, thanks!

1. How the Von = 2V comes from? Is it means when the input voltage of V_IT=2.5V, the output voltage will be Vo=2V? How to calculate it?

2. What is the input serial resistor for? As well as the BJT? How this circuit function?

  • 0
    TI__Mastermind 19580 points
    Hi Fery,

    I can assist you with this.

    1. The 2V is actually a 1.8V to 2V output. This has to do with how the output is not fully off and the device still needs voltage to function. If you want an example of the output voltage check out this previous E2E thread. There is a graph that shows IKA vs VKA
    e2e.ti.com/.../469930

    2. The BJT is there to allow for a higher current to be shunted. The TL431 has a output current of 150mA but at high voltages and high currents there can be thermal issues. By shunting the current through the BJT it is possible to get >150mA at high voltages.
    The resistor is there to create the voltage drop for VI(BATT) to Vo. With out the resistor it is not possible to create a voltage difference Vo. This is because the output of this circuit is now Vo and not the Vka.

    -Marcoo