Hi All,

i've just simulated a comparator on LTSpice and it seem to get what i expected. Now i wish to know if there would be any change in the way the comparator would work when using an LT1018 and a MIC7221YM5-TR. The LT is a bit too expensive compared to the Microchip.

My circuit is a comparator as seen below.

Thanks in advance.

 

You can answer that by doing a quick comparison of data sheets.

I would look at input CM range, speed, output I drive, output CM range,
supply ratings, offset as a first order comparison.

Regards, Dana.

 

can't really determine if it can be a drop-in replacement as this is my first time using a comparator.

 

hi anish,
Please post the datasheets for the two types and we can check them out for you.
E

 

I wouldn't think the comparator type was critical for that battery-voltage monitoring circuit.

 

MIC6270YM5-TR - What i plan to use
LT1018 - Seen in the simulation

 

hi anish,
I would say that the MIC would work OK in that circuit, note the +10V limit on Vsupply.
E

EDIT:
Post your LTS asc file.

 

Thank you Eric.

Yes i did note it. hence the voltage has been scaled down.

 

i am just not sure about the values, if i have to stock a few more or just those mentioned in the simulation.

 

What are the sources for the three voltages?

 

Main one being an18650 Battery and other two regulated via Zener.

 

Main one being an18650 Battery and other two regulated via Zener.

hi

Added a little hysteresis (50mv).
Led will light at about 24.8v
You could also replace the comparator with an LM339 is you like.
And/or V2 with a TL431.

eT

 

Initially the led will light up at 16.8 and will stay ON till it reaches 24v or close to it.

 

Initially the led will light up at 16.8 and will stay ON till it reaches 24v or close to it.

Hello

This is what a simulation of your circuit produces:


So...you only want the LED on from 16.8v to 24v?
Then it will need a window comparator...

Is the whole circuit going to run from the battery?

eT

 

Yes it would be running from the battery only. The idea is to detect when the battery goes below 16.8v, that would be 2.8v/cell and that would light up the LED as an indicator that the pack has gone beyond the set voltage.

 

Not sure how you got that waveform when i see this

 

You could eliminate V2, R3, R6 and just tap off a voltage from V3.

 

Yes it would be running from the battery only. The idea is to detect when the battery goes below 16.8v, that would be 2.8v/cell and that would light up the LED as an indicator that the pack has gone beyond the set voltage.

umm...ok..

You stated yes...(indicating you want the LED on from16.8-24v) but you now state you want it on when the battery is below 16.8 volts..

Which one is it?

 

Not sure how you got that waveform when i see this
View attachment 170889

I just swept the battery voltage up from 0 to 26v.

 

umm...ok..

You stated yes...(indicating you want the LED on from16.8-24v) but you now state you want it on when the battery is below 16.8 volts..

Which one is it?

Sorry about the confusion, the LED will light up when the voltage hits 16.8v and will stay on till it reaches 24v.