4mA-20mA to Fixed 3.3V current to voltage converter

Thread Starter

ashokchandra

Joined May 13, 2018
37
Hi ,

Please suggest me a 4mA-20mA to Fixed 3.3V current to voltage converter.
Input range : 4mA to 20mA Current From sensor.
Output : 3.3V @10mA Fixedt output Voltage.

Thanks,
Ashok
 

ericgibbs

Joined Jan 29, 2010
9,556
Input range : 4mA to 20mA Current From sensor.
Output : 3.3V @10mA Fixed output Voltage.
I Have to generate fixed 3.3V from 4mA-20mA Current.not from external 3.3V.
hi ashok,
When the current loop is less than 10mA, ie: say 4mA thru 9.9mA, how is the 10mA at 3.3v going to be generated.?

Perhaps it would help if you said what the purpose is of the project, there maybe alternative solutions.
E
 

Thread Starter

ashokchandra

Joined May 13, 2018
37
hi ashok,
When the current loop is less than 10mA, ie: say 4mA thru 9.9mA, how is the 10mA at 3.3v going to be generated.?

Perhaps it would help if you said what the purpose is of the project, there maybe alternative solutions.
E
Hi,
purpose is to turn on the micro-controller from sensor i e(4mA-20mA Current). but micro-controller needs constant 3.3V.

Thanks,
Ashok
 

ericgibbs

Joined Jan 29, 2010
9,556
hi,
It is not possible to increase the power out to 3.3v at 10mA, from a < 10mA source.
I would say you need a external 3.3v source able to supply 10mA.
E
 

Thread Starter

ashokchandra

Joined May 13, 2018
37
hi,
It is not possible to increase the power out to 3.3v at 10mA, from a < 10mA source.
I would say you need a external 3.3v source able to supply 10mA.
E
Hi,

Our Project concept is to get 3.3V from 4mA to 20mA current from sensor.
suggest me converter which converts 4mA-20mA current to 3.3V voltage.
Thanks,
Ashok
 

dendad

Joined Feb 20, 2016
3,317
Are you trying to get a 3.3V power supply for a sensor from the loop current, or something like that?
You do need to give us more info if you want us to help. So far, your question is pretty confusing.
Please explain your application in detail.
For example, what is the voltage driving the 4-20mA loop?
Is this a sensor supply?
Just in a linear mode, it is impossible to get a 3.3V 10mA supply from a 4-20mA loop current. So, as said above, you really do need to explain what you want in detail.
 

Thread Starter

ashokchandra

Joined May 13, 2018
37
Are you trying to get a 3.3V power supply for a sensor from the loop current, or something like that?
You do need to give us more info if you want us to help. So far, your question is pretty confusing.
Please explain your application in detail.
For example, what is the voltage driving the 4-20mA loop?
Is this a sensor supply?
Just in a linear mode, it is impossible to get a 3.3V 10mA supply from a 4-20mA loop current. So, as said above, you really do need to explain what you want in detail.
Hi dendad,
The sensor which i am using is giving current as output .When i measure the output current from the sensor its in the range : 4mA-20mA.
So the above current (generated from the sensor) , i need to convert it to a fixed voltage = 3.3V, which in turn i need it to turn ON a micro-controller.
Kindly, suggest me the component/circuits to convert variable-current to a fixed voltage(=3.3V) i.e. from 4mA-20mA to fixed 3.3V voltage to turn on the micro controller
Thanks,
Ashok
 

dendad

Joined Feb 20, 2016
3,317
Hi dendad,
The sensor which i am using is giving current as output .When i measure the output current from the sensor its in the range : 4mA-20mA.
So the above current (generated from the sensor) , i need to convert it to a fixed voltage = 3.3V, which in turn i need it to turn ON a micro-controller.
Kindly, suggest me the component/circuits to convert variable-current to a fixed voltage(=3.3V) i.e. from 4mA-20mA to fixed 3.3V voltage to turn on the micro controller
Thanks,
Ashok
Ok Ashok.
You need to find what current the micro needs to run. If it is over the 4mA, the project gets more complicated. With a linear regulator, you cannot get any more current out that the supply input. In this case, the max current available for the micro is determined by the minimun loop current, and that is 4mA.
If your micro needs more current, a switch mode supply will be required, and the loop supply voltage will need to be high enough to allow 4mA input to the switch mode supply, at sufficient voltage to produce the required output current. It is not quite a simple arrangement, to keep the current stable and the micro supply voltage stable at the same time. This is why I ask again, MORE INFO please.
Why do you need to power the micro from the loop current?
What is the supply voltage?
What is the sensor?
Circuit, or at least a block diagram please.
If you will not supply info, it is really hard to help you.

Usually, the current is not "generated" by the sensor, it just controls it. There is an external supply, usually at the micro end. So the micro supply power is not a problem.
(Oh, I design industrial control equipment for a living.)
 
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