How to divide a clock by 2.5 with digital circuit?

[meetspraveen]

how to divide a clock by 2.5 with digital circuit?

 

[vsmGuy]

CLOCK DIVIDE

Solutions range from F/F to CMOS processes.. can you be more specific ?

 

[Kral]

Re: CLOCK DIVIDE

meetspraveen,
Connect the clock input to an XOR gate.
Connect the other input to a string consisting of an odd number of inverters. Connect the last stage of the inverter string to the other input of the gate. This produces a pulse train at the output of the XOR that is twice the clock frequency. The duration of each pulse will depend on the delay trhought the inverters. Divide the pulse train by 5 using a divide by 5 counter.
Regards,
Kral

 

[vsmGuy]

CLOCK DIVIDE

@Kral...

Correct me if I am wrong, but this circuit works good in theory but time drift response is not very stable across temperature changes and input voltage fluctuations...

And the gates need to be of same type too !

 

[melc]

Re: CLOCK DIVIDE

https://focus.ti.com/paramsearch/do...85&navigationId=11385&family=logic¶mTable=yes

https://focus.ti.com/docs/prod/folders/print/cd4527b.html

 

[vsmGuy]

CLOCK DIVIDE

@melc
Great thinking !

Ay idea about a divide by 10 logic BUT which maintains the duty cycle ?

 

[Kral]

Re: CLOCK DIVIDE

vsmGuy,
You are correct regarding parameter changes with voltage and temperature. However, the width of the pulse output of the XOR is not critical. You just have to ensure that the total delay through the inverters is long enought to produce the minimum acceptable pulse width in order for the divide by 5 counte to respond.
Regards,
Kral

 

[vsmGuy]

CLOCK DIVIDE

@Kral

Oh.. I forgot to tell you that I have actually been making these circuits for a while... so I know about their reliability. But these are a very good test for a engineer's digital logic fundamentals.

But if you noticed, I am on the lookout for idea about a divide by 10 logic BUT which maintains the duty cycle.

Any pointers ?

 

[nguyennam]

Re: CLOCK DIVIDE

how to divide a clock by 2.5 with digital circuit?

I do not know who to divide by 2.5 with the digital IC, but with an op amp, you can easily make a divider of any ratio between x.1 to x.9.

nguyennam

 

[omara007]

Re: CLOCK DIVIDE

how to divide a clock by 2.5 with digital circuit?

In this document you will find exactly what you are search for :

h**p://

 

[vsmGuy]

Re: CLOCK DIVIDE

how to divide a clock by 2.5 with digital circuit?

I do not know who to divide by 2.5 with the digital IC, but with an op amp, you can easily make a divider of any ratio between x.1 to x.9.

nguyennam

Can it divide by 10.1 ?

Can you give more details about this ? I am nt aware of a freq divider using opamps.

 

[Kral]

Re: CLOCK DIVIDE

vsmGuy,
Do you mean a crcuit that divides the input clock frequency by 10 and maintains the duty cycle of the input clock?
Regards,
Kral

 

[vsmGuy]

CLOCK DIVIDE

@Kral

That's EXACTLY what I want ! Maybe I was not clear..

You have a solution ?