Hello!
I have an application requiring me to individually control up to 5 miniature proportional valves with the output of a microcontroller (0-5V). Preferably this will be done by up to 5 PWM channels or even by serial communication if there exists an IC capable of managing this many valves at a time while only using one or two serial buses. Resolution and response time are both factors to consider as well though I'm not entirely sure of the exact specs required. In any case, my PWM only has 256 possible duty cycle values and I'm fairly certain the mechanical response of the valve will always be much slower than the control signal's ability to change (i.e. <10ms)
The real challenge I'm seeing is that many of the suggested drivers for solenoid control (at least from what I've seen on these forums sofar) lack current control to be able to properly drive these valves proportionally with feedback. Or it may be that I'm not understanding their capabilities correctly?
I've read discussions on the LM3410 and INA138 as possible solutions; however, these ICs would control only one valve at a time and I was hoping for something more comprehensive. Another driver I was interested in was the DRV8860 which could control up to 8 devices but lacks current control as best as I can tell. Other ICs seem to provide a degree of current control but not with a very decent resolution. Lastly, the DRV777 is another driver mentioned which could fit the bill though the max current output per channel is low and its input to reach this max is only ~2.5V, effectively cutting my resolution in half.
While I did mention a number of devices here, I am open to any other IC that could work. Just figured I'd cover where I've already been.
For the record, the valves I'm interested in using take a supply voltage of approximately 13.5V and require a current of 125mA to achieve full flow.
The specific valve is attached along with a picture detailing the suggested analog circuit. (Please visit the site to view this file)
Thank you for reading,
-Caleb