Datasheet understanding

It can be used that way, the voltage isn't an issue because it is current operated, you change the value of Rx (on the data sheet) to set the threshold you want.

Brian.

betwixt said:

It can be used that way, the voltage isn't an issue because it is current operated, you change the value of Rx (on the data sheet) to set the threshold you want.

Brian.

Click to expand...

And if I want the "default" threshold (around 3v is ok for me)? Do I connect directly the battery to the terminals of the component? But I need something to limit the current?

You need to use a voltage divider as discussed at datasheet page 12.

FvM said:

You need to use a voltage divider as discussed at datasheet page 12.

Click to expand...

I need solution with galvanic isolation to detwct the presence of the voltage. And the solution needs to be power efficient. Voltage devider will consume so much energy from my battery. Do you have some advice how can I do this voltage detection without drawing to much power from the battery?

I run out of more ideas.

Thanks people you are saving my day !

Hi,

kotnikyeah said:

Do I connect directly the battery to the terminals of the component? But I need something to limit the current?

Click to expand...

Brian already mentioned the use of Rx.
Thus refer to Figure 13 of the datasheet, follow description.

****
Now I see current consuption is a problem.
Please tell us your upper limit of average current consumption from the battery. Please a value with unit.

There will be a solution in either case. But the more you go to an extreme (like microampere current consumtion) the more effort and the more expensive it will become.

You could also tell us the battery chemistry and how much Ah it has.

Klaus

KlausST said:

Hi,

Brian already mentioned the use of Rx.
Thus refer to Figure 13 of the datasheet, follow description.

****
Now I see current consuption is a problem.
Please tell us your upper limit of average current consumption from the battery. Please a value with unit.

There will be a solution in either case. But the more you go to an extreme (like microampere current consumtion) the more effort and the more expensive it will become.

You could also tell us the battery chemistry and how much Ah it has.

Klaus

Click to expand...

KlausST said:

Hi,

Brian already mentioned the use of Rx.
Thus refer to Figure 13 of the datasheet, follow description.

****
Now I see current consuption is a problem.
Please tell us your upper limit of average current consumption from the battery. Please a value with unit.

There will be a solution in either case. But the more you go to an extreme (like microampere current consumtion) the more effort and the more expensive it will become.

You could also tell us the battery chemistry and how much Ah it has.

Klaus

Click to expand...

Thanks !

The smallest variant battery is 5Ah and I want to avoid draining it too fast because of this measurement.
Battery is LiFePO4. I would say my upper current limit is anything that will not drain my battery fast ( for example in few days). Important is that the design remains quite semi-simple, not some overkill electronics with so many components and so expensive. I would be more precise but now I am unable to be more precise than this.

Hi,

not that much "numbers and units" I expected.

But anyways. 5Ah and "a few days".
Let´s say 7 days. this is 168h
5Ah / 168h = 0.02976A = 29.76mA

The detector needs at least 1.5mA, so you have plenty of headroom.

*****
Simple method to extend battery lifetime: Switch from continous operation to pulsed operation.
A battery does not discharge that fast, so maybe it´s sufficent to get an information about the battery state once per 10 seconds.
So build some kind of "pulse generator" that is ON for 0.1s and OFF for 10s.

So the detector just needs to operate 1% of time .. and thus consumes just 1% power (averaged).

***
I dont know how experieced you are with building electronics, or maybe even microcontrollers.
So there are countless ways...

Give us some information about your skills, the effort you like to spend, the requirements in timing ....
... and we can discuss a good solution for you.

Klaus