in the below image,,,there is a constant current load by which i want to draw 1A currnet. but once the capacitor is charged around 60%, then this 1A should start to flow.Hi,
I don´t understand what you want to do. Please draw a sketch.
Klaus
I didn't get it,,can you explain a bit more?For any case just sim a cap and spec its charge with an initial condition.
Regards, Dana.
or any diagram,,,For any case just sim a cap and spec its charge with an initial condition.
Regards, Dana.
well I tried as per your suggestion...Is the attached any good to you?.....it is in LTspice
It discharges the cap when its gone down to half of 10v
Also maximum 2 V drop is allowed across R1, after final charging.
if you consider maximum R=2 ohm then how much inrush current will flow...if i ma not wrong,,,then it should be 42/2 = 21A,,,and maximum limit is 3A.Hi,
to no confuse yourself ( and me) I recommend to change only one parameter.
* now it´s 63%
* now it´s a 3A limit
* not it´s a 15 Ohms resistor.
use Ohm´s law:
For max 2V drop on a 1A load --> R must not be higher than 2 Ohms.
Klaus
Although I have stated 2 times again,,i don't know you have read these comments or not.It seems to me, (and I’m probably wrong based on the OP‘s inability to clearly and consistently state his objective) that what’s wanted here is a constant current source that’s switched on when the voltage reaches some threshold. A comparator plus a current source would do it, no?
It´s a problem of your requirements. They can´t match. At least not with the given circuit.and maximum limit is 3A.
so now?
Why that agressive?Although I have stated 2 times again,,i don't know you have read these comments or not.
one more time again...for your reference open the post 8, zip file,,,
There i want to draw 500 mA constant current , once the cap is charged around 63% of initial voltage.
here some conditions are there: maximum inrush current allowed is 3A, cap should be charged in less than 200ms.
and after final charging maximum voltage drop allowed at R1 is 2V.
so now ?
Don't be a jerk.Although I have stated 2 times again,,i don't know you have read these comments or not.
one more time again...for your reference open the post 8, zip file,,,
There i want to draw 500 mA constant current , once the cap is charged around 63% of initial voltage.
here some conditions are there: maximum inrush current allowed is 3A, cap should be charged in less than 200ms.
and after final charging maximum voltage drop allowed at R1 is 2V.
so now ?
Sorry if you feel like that.It´s a problem of your requirements. They can´t match. At least not with the given circuit.
Why that agressive?
For me speaking: on my tablet I can´t open zip files. Maybe others have the same problem.
So I didn´t open the zip file either.
Now again the current changed to 500mA.
Still you did not follow our recommendation to use a comparator in the simulation to control the constant current.
And you did ingore that .. as soon as the load is switched ON the voltage can not rise anymore .. it will tumble around this threshold level randomly .. so what "final charging maximum voltage" are you talking about?
So please don´t blame it on us if the circuit does not work the way you think it should work.
I still miss a clear definiton with the expected timing diagram.
Klaus
An appropriate term is self-contradictory....somewhere system requirement is not perfect
I already knew that 3A is the inrush current and 0.5A is the constant current.This 500mA is current which will drawn by constant current source continuously. While 3A was maximum inrush current that can flow to capacitor.
sorry for such a big confusion. I checked it, it was a mistake.Hi,
I already knew that 3A is the inrush current and 0.5A is the constant current.
What I´m talking is: now the constant current is 0.5A but before it was 1A. This has changed (as so many other things).
If the requirement is "just a current between 0.5A and 1A" then a simple resistor could be a fairly good solution.
I just try to support you and give a good solution. But for this I need to understand the requirement.
At first it seemd that 1A is a "true requirement". But when this changes to 0.5A ... it tells me that this was not a true requirement. Thus I tried to find out what function (without referring to your circuit) you really need.
I failed to help because I failed to find out what´s important for you.
Klau
Again: what do you consider as "the final charging" ?My question: is it possible to reduce the voltage drop across (vin , vout)) less than 1V, without changing the inrush current condition (3A), after the final charging.
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