Motor drive applications can also require power supplies with controlled output current.
Combining the two difference stages' output currents yields four-quadrant operation.
In saturation, the stage produces a nearly constant output current.
In these circuits, the output current is not monitored and controlled by means of negative feedback.
As a result, the output current is almost constant even if the load resistance and/or voltage vary.
Since power () must be conserved, the output current is lower than the source current.
Note that with the circuit as shown, if V changes, the output current will change.
The value of 2.2 kilohms allows an output current of about 7mA.
The output current of a smart charger depends upon the battery's state.
This is not possible in the Wilson configuration while maintaining an accurate match of the input current to the output currents.
