Voltage reference sets current limit
The current-limit circuit in Figure 1 allows you to establish the setpoint by applying a voltage to one of the amplifier’s pins. With this design, it is possible to set the current-limit point with the output of a DAC, possibly under the control of an embedded µC. The OPA547 is a true op amp; thus, it does not need a connection to power ground.
Source:http://www.edn.com/archives/1998/111998/24di.htm
