• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 62 subscribers
  • Views 259 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TL783: Add 50V zener diode between the source and input

Danilo A.
Mastermind 29435 points
Part Number: TL783


Hi Team,

Our customer would like to generate an output voltage from 88V to 167V @ 75mA output current using the TL783 from an input voltage of 250V. Since the differential voltage exceeds the maximum Vi-Vo of 125V, he would like to know if he can put a series zener diode between the 250V source and the input of the TL783 to reduce the voltage by 50V. Will this work?

Regards,

Danilo

  • +1
    TI__Genius 12960 points

    Hello Danilo,

                        Theoretically speaking, it could work and the customer could do this. However, for it to work, the customer would require a 50V Zener diode that can sustain 3.75W (50V*0.075A) of continuous power dissipation. The inrush current of the LDO at startup could be significantly higher than 75mA (could be as high as 400mA) and the diode would need to be able to handle this current too (albeit for a short period of time). 

                         Perhaps a simpler solution would be use another TL783, instead of the Zener diode, to step down the voltage. Either ways (diode or LDO) I would urge the customer to verify if the application setup would meet all their requirements before scaling it. Thanks!

    Regards,

    Srikanth