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TL1431: Window comparator with for a +270V supply

Ciro Longobardi
Prodigy 20 points
Part Number: TL1431

Hello!

I would like to use the TL1431 as a window comparator as depicted in Figure 34. Voltage Monitor of TL1431, TL1431M  SLVS062N datasheet. 

The main issue is the voltage that I should monitor. It is a +270Vdc. Any suggestion please?

Best Regards,

Ciro 

  • 0
    TI__Mastermind 19580 points

    Hi Ciro,

    I can help you with this solution with the TL1431.

    Can you help me better understand your system?

    Do you only have a 270VDC rail that can be used?

    What is the output voltage needed?

    What is the desired window?

    -Marcoo

  • 0 in reply to Marcoo Z
    Prodigy 20 points

    Hi Marcoo,

    of course I can better describe the system.

    I have a +270Vdc supply and I need to fix two thresholds in order to detect respectively OVERVOLTAGE (+365V) and UNDERVOLTAGE (+220V) conditions.

    I already used the TL1431 as depicted in the picture below:

      

    when the +28VLOGIC supply is greater than 17.65V then the photocoupler is turned on and the +28VLOGIC_MON signal is at HLL (3.3V)

    I would like to use the same approach for the +270V rail with two thresholds as described above.

    -Ciro

  • 0 in reply to Ciro Longobardi
    TI__Mastermind 19580 points

    Hi Ciro,

    if you need the TL1431 to work at higher voltages you would need a step down. The cathode of the TL1431 cannot handle 270V in comparator mode when the output is logic high. You can use a 2nd TL1431 to create a step down voltage to 26V for the cathode.

    -Marcoo.