Voltage (0 to 10V) to Current (0 to 20 mA) Converter

[khanna_gunjan]

voltage-controlled current transmitter

Hello,

I am using a 12 Bit Voltage DAC along with the gain Amplifier Circuit to generate 0 to 10V Voltage Output, Further i would like to convert this Voltage Output to 0 to 20mA without losing the accuracy of the circuit.

Could Anyone please suggest me a simple and compact circuit for such a application.

Thanks in advance for your time and support.

Gunjan

 

[Old Nick]

convert current voltage 0 10 v

A transconductance amplifier (voltage controlled current source) is what you're after.

 

[Prototyp_V1.0]

voltage.0

It's very easy to make current from voltage using an opamp.

Also the formula is very easy:
\[I = \frac{U}{R}\]
The value of the other resistor (the unamed one) doesn't matter. I guess a greater than zero make it a litle bit more acurate.

 

[Siniša]

From Prototyp_V1.0's schematic posted above you could see that "unnamed" resistor is your load, or receiving device. It is obvious that other end will have to be floating or it has to have instrumentation amplifier in order to convert signal to be referenced to 0V. Other option is to have ground referenced current source, but for that you will need instrumentation amplifier on transmitter end. Either way, you have to use instrumentation amplifier, so why not use it on transmitter end?
Because you require accuracy 13 bit or better, instrumentation amp (IA) is a must, as for building IA from scratch will be hard to match resistors for good CMRR.
Even better is already built transmitter like XTR101. Almoust every instrumentation amp data sheet includes app.diag. for building current transmitter. Don't forget that with 12bit DAC if you want transmission error to be limited to ±0.5LSB it means total budget for resistor errors, nonlinearity, temperature drifts, noise, interference, thermocoule effects,tribolectric effects,... is less than ±0.05% ! You will surelly lose some of the accuracy, question is how much. You have to account for all sources of error and address each one of them in order to bring this down to a minimum. Details of your design, like what is receiver of signal, how far signal has to go, what is enviroment you use this in and many others will determine what really can be achieved at acceptable cost. If accuracy is most important parameter of your design, might be more effective if D/A conversion is done on the receiver end.