adjustable current source or sink

[HMaier]

I need a design hint for a adjustable current sink or current source.
I want to control the current through a solenoid (hydraulic control). The current must be adjustable by a voltage (DAC). It should be a closed loop control. The current is in the range from 50mA to 1500mA. The supply voltage is 28V. It should be a switched mode Design.

Hope I get some good ideas

Rgz HMaier

 

[7rots51]

I suggest you see analog device application notes and datasheets of this ICs this give you good ideas.

AD420,AD421,AD693,AD694

www.analog.com

ok :wink:

 

[coppervaporlaser]

RE: .... adjustable current sink or current source

Hi !

Use a shunt resistor (eg 1ohm for 1.5V drop @ max current) -> the current valve should be a high power mosfet (use IRF types or good old BUZ).
than take a opamp (which is able to overdrive the fet for the necessary current) and connect one feedback to the resistor.

 

[DavidP]

A simple circuit can be built around the LM350 used as a current source. Check Motorola data and apps.