comparitor stability
comparitor stability
(OP)
Hey!
I am having difficulty stabilizing the output of a op amp comparitor in my circuit. As the positive input changes and approaches the reference voltage at the negative input, the output doesnt stay stable at a high state. The next device in my circuit which detects a high to low transition is picking up on every little change at the comparitor output.
Neo11
I am having difficulty stabilizing the output of a op amp comparitor in my circuit. As the positive input changes and approaches the reference voltage at the negative input, the output doesnt stay stable at a high state. The next device in my circuit which detects a high to low transition is picking up on every little change at the comparitor output.
Neo11





RE: comparitor stability
<nbucska@pcperipherals.com>
RE: comparitor stability
by using positive fidback.
if you dunno what is a schmitt trigger you can contact me
by this email address:
kasra_ravanbakhsh@hotmail.com
or see any electronic books!!!!
such as Integrated Electronics by Millman-Halkias
McGraw-Hill Book company
RE: comparitor stability
adding an ST after the comparator doesn't.
<nbucska@pcperipherals.com>
RE: comparitor stability
1. DC (using a feedback resistor to the positive input)
2. AC + DC (using a feedback resistor in parallel with a
feedback cap with a additional resistor in series
with the cap, to the positive input)
Selecting one of the two to give the best results will depend upon your noise levels, shielding, S/N ratio and input signal type (fast/slow level changes). As a hint the feedback resistor values are usually very large to allow only 0.01 to 1% feedback and the caps are usually very small to allow faster switching (10 to 220pF typ) the resistor in series with this cap is usually 1/4 to 4x the value of the input resistance that feeds the comparitor ckt.
Hope this helps...
RE: comparitor stability
1. Please, could you describe the hardware and application a little, e.g. is it analog or digital comparator, high or low speed, two variable or one variable and constant, differential voltage comparator, etc.
2. Visit
http://www.ti.com/sc/docs/psheets/diagrams/ontranl_a.htm
http://www-s.ti.com/sc/psheets/sboa081/sboa081.pdf
http://www-s.ti.com/sc/psheets/slcs119/slcs119.pdf#xml=http://www-search.ti.com/search97cgi/s97_cgi?action=View&VdkVgwKey=http%3A%2F%2Fwww%2Ds%2Eti%2Ecom%2Fsc%2Fpsheets%2Fslcs119%2Fslcs119%2Epdf&doctype=xml&Collection=TechDocs&QueryZip=%3CACCRUE%3E%28%5B90%5D%28comparator%29+%3CIN%3E+Keywords%2C+%5B85%5D%28comparator%29+%3CIN%3E+Title%2C+%5B70%5D%28%28%28comparator%29+%3CIN%3E+Body+%3CAND%3E+%3CNOT%3E+%28comparator%29+%3CIN%3E+A%29+%3COR%3E+%28comparator%29+%3CIN%3E+Page%29%2C+%5B10%5D%28comparator%29+%3CIN%3E+A%29&
etc. for more info