• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 17 subscribers
  • Views 666 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

about CD4541B programmable timer (reseting and self-reprogramming)

Vitali Moilanen
Prodigy 10 points

I want to use programmable timer in our circuit. But I need only short OFF-state, but long ON-state on the output. I chose CD4541B-timer. Now I have some question, becase I did't found answers from datasheets. 1) Is it possible to change frequency selection "on-the-fly" by contol it with output from Q? So, if I can change count by changing B-state from 256 to 65536. Is there some risk, that timer may hang at this operation? (see picture) 2) Is it possible to use RC for Master reset, when power is on? In a product, where this circuit is will be used may some problem with "ringing contacts", when power is on and off. If reset with RC is possible, what values is recomended for R and C? (see picture). I want to use timer with voltage range form 4 to 6,5 V. If I understund right, I can't use Autoreset, when power is under 5 V?

Picture: http://aijaa.com/img/b/00401/13047013.jpg
  • 0
    TI__Mastermind 46480 points

    1) Is it possible to change frequency selection "on-the-fly" by contol it with output from Q? So, if I can change count by changing B-state from 256 to 65536. Is there some risk, that timer may hang at this operation? (see picture)  I dont  believe it would hang up but I dont know if the first count would be right

    2) Is it possible to use RC for Master reset, when power is on? Yes this is OK

     In a product, where this circuit is will be used may some problem with "ringing contacts", when power is on and off. If reset with RC is possible, what values is recomended for R and C? (see picture). An R/C can be used . This pin has no rise and fall spec so I am unsure how slow the edge can be. You will have to experiment and a schmitt trigger may need to be added on thast signal.

    I want to use timer with voltage range form 4 to 6,5 V. If I understund right, I can't use Autoreset, when power is under 5 V? auto reset can only be used at power up