What is the rise time of the DCI when the external resistance changes?
For example, if the external resistance changes from 50 to 45 ohms, how long will it take the DCI to converge to 45 ohms?
The voltage across the reference resistor is sampled ~ 100,000 times a second. If the resistance changes, the voltage changes, and the current will change within a few 10's of us. The DCI will converge on the setpoint in a few 10's of microseconds in very small, linearly increasing or decreasing current steps.
NOTE: For related information, see (Xilinx Answer 11814).