Other Parts Discussed in Thread: DAC7571, DRV8876
Tool/software:
Hello TI,
I need to control proportional pneumatic valve with closed-loop current regulator.
Looking thru TI portfolio, together with Matthew Calvo, we found possible solution, but I would like you to confirm that it will work as expected.
The idea is to use DRV8235 and set it to Fixed Off-Time Current Chopping. To be able to control the target current, we will pick IPROPI resistor to cover whole expected current range (up to 600mA) and drive VREF with DAC instead of fixed voltage. So the DAC (for example DAC7571) will be used to set target current.
Can this approach be used, or it will not work? If yes, do you have any idea about the speed of the regulation loop? If the VREF for example will be changed by 10%, how long it takes to have the load current changed?
Are there any limitations, that we should take into account (load parameters? inductance? )
BTW ... we initially taught we could use DRV8876, but DRV8235 is cheaper and all the discrete inputs (EN, etc.) can be controlled via I2C, which is a benefit for us.
Thank you,
Zbynek
