How to solve the glitch of digital circuit

[EDA_hg81]

circuit glitch

When power on the digital circuit built with discrete components, look all those components generate glitch during initial transition time.

How to fix them?

Do you know any anti glitch circuit?

Thanks.

 

[A.Anand Srinivasan]

glitches in digital circuits

glitch can be smoothened by the usage of capacitor from the supply to the ground.... 0.01µ and 0.1µ are the commonly used values.....

 

[EDA_hg81]

glitch circuit

But how to eliminate glitches?

Thanks

 

[RBB]

anti glitch circuit

There are a couple of ways to remove glitches.
1. Sample the signal the glitch appears on via a flop.
2. Grey encode the flops that may be causing the glitch.

 

[A.Anand Srinivasan]

glitches in a digital circuit

I think hg81 is talking about eliminating glitch during power on....
that glitch occurs due to the sudden surge of current and i think using the capacitor is the best way to eliminate that glitch.... you would find most circuits with a capacitor for this purpose.....

hg81 if you can post your circuit it would be even better...

 

[rowokii]

glitch on power supply

It's going to be hard to get rid of all the "glitch" from the circuits when they are first turned on. Power supply is ramping up and there are unknown logic states everywhere. A power supply decoupling that Anand is suggesting will not work since it only helps to reduce power supply noise. It will not do anything about outputs switching due to unknown logic states.

Most systems deals with power on by having a power-on-reset (POR) circuit. It allows for the supply voltages to reach a stable voltage and make the system reset to a known state before doing useful work.

One simple way to make a POR circuit is to put a RC circuit between the power and ground. The middle node is connected to a schmitt trigger buffer and output is used as reset. There are commercial POR circuits as well that comes in a three pin package.

Cheers

 

[EDA_hg81]

glitches in circuits

rowokii and A.Anand Srinivasan

Thank you so much for your help.