current driver is saturated problem

[yefj]

Hello ,I have built a PID controller which is connected to differential driver by the manuals below.
The PID is single ended while the driver is differential so I connected the two using converter.
The key component is the integrator.
I want that the driver to create a current on the load so It will be following the integrator output signal.
However as you can see that as integrator output rises the driver current saturated as some point .
Is there a way to fix the driver so it wont sature so quickly?
Ltspice files are attached.

https://www.analog.com/en/resources...ne-driver-receiver-design-guide-part-two.html
https://www.analog.com/en/resources...n-single-ended-to-differential-converter.html

 

[rjenkinsgb]

PIDs are normally used in closed-loop systems; they allow the control to match the part being controlled by giving an approximate command signal (proportional) adjusted to compensate for load (the integrator) and control overshoot (the differentiator).

Your setup is open loop, so the parameters are pretty meaningless - the integrator will ramp out of control.

The input to the PID should be a difference (error) value between the target setpoint and load output.