A further disadvantage is that the voltage seen by the load will change by an amount equal to the difference between the voltage setting of the individual models as each one goes into its current limit, passing voltage control to the next lowest unit. Units 1 and 2 merely add current I1 and I2 to the total and operate in their current limit mode. A complementary situation will prevail if current sources are connected in series. Only ONE current stabilizer can control the current in a single loop. All of the others will overload to their voltage mode, merely supplying voltage to the load, but not controlling the current.
Adjustment is tricky however.
All units must be set to the same voltage and re-adjusted carefully to share the current. The current sharing circuit is a form of master-slave operation in which the current supplied by the master is measured and the other units are controlled to match the current, ensuring that they are equally loaded. Only the master actually controls the voltage to the load. In modern fault tolerant power supply systems, a means is provided for forced current sharing . This ensures that all units carry an equal part of the burden.