User`s guide

Appendix E Source Operating Modes
122 Series N6700 User’s Guide
Agilent N678xA Multi-Quadrant Operation
Agilent Models N678xA SMU can be operated in either voltage or
current priority mode. They can source as well as sink output power.
Note that Agilent Models N6781A and N6782A operate only in the
+ Voltage quadrants.
Voltage Priority Mode
In voltage priority mode, the output voltage should be programmed to
the desired positive or negative value. A positive current limit value
should also be set. The current limit should always be set higher than
the actual output current requirement of the external load. With
tracking enabled, the negative current limit tracks the positive
current limit setting. With tracking disabled, you can set different
values for the positive and negative current limits.
The following figure shows the voltage priority operating locus of the
power modules. The area in the white quadrants shows the output as
a source (sourcing power). The area in the shaded quadrants shows
the output as a load (sinking power).
Key
Sourcing power
Sinking power
Programmable
V setting
-I limit +I limit
+20 V /
+6 V
-20 V /
-6 V
+1 A /
+3 A
-1 A /
-3 A
+OV
−OV
− Voltage
operation
applies to
N6784A
only
+ Voltage
+ Current
The heavy solid line illustrates the locus of possible operating points
as a function of the output load. As shown by the horizontal portion
of the line, the output voltage remains regulated at its programmed
setting as long as the load current remains within the positive or
negative current limit setting. A CV (constant voltage) status flag
indicates that the output current is within the limit settings.