Voltage controled current source with grounded loads.

[Sheldoniq]

I need current source 0 -10mA for measure PTC thermocouple (various resistance)
This means that the load must be grounded!
I use any as (see pic)with digital potentiometer and LM4041, but it is complicated for me and I I am seeking something that would be to drive DAC 0 - 2.5V
An idea for a simple voltage controlled current source?

 

[D.A.(Tony)Stewart]

With a ground side current sense under the load and feedback gain Rf instead of unity (Rf=0), you now have a VCVS where you define the V/mA ratio based on Rf.

 

[carpenter]

See on page 17 AD8276

 

[crutschow]

Perhaps this circuit would work for you.
You change Rsense to 250Ω to get the voltage-in to current-out gain you want (2.5V in for 10mA out).

 

[carpenter]

I thing this is not very accuracy, becouse shifting voltage V+ over R5 shifts the output current and V+ is power voltage.

 

[KlausST]

Hi,

google for "high side constant current circuit"

Klaus