Keysight Technologies RP7900 Series, Operating And Service Manual

Page: 164 / 318

Priority Mode Tutorial
Voltage Priority
Current Priority
Voltage Priority
In voltage priority mode, the output is controlled by a constant-voltage feedback loop, which
maintains the output voltage at its programmed setting as long as the load current remains within the
positive or negative current limit settings. Voltage priority mode is best suited for use with resistive or
high impedance loads, and loads that are sensitive to voltage overshoots. Do not use voltage priority
mode with low-impedance sources such as batteries, power supplies, or large charged capacitors.
In voltage priority mode, the output voltage should be programmed to the desired value. A positive
and negative current limit value should also be set. The current limit should always be set to a value
that is greater than the actual output current requirement of the external load. The following figure
shows the voltage priority operating locus of the output. 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).
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 voltage is being regulated and
the output current is within its limit settings.
Note that when the output current reaches either the positive or negative current limit, the unit no
longer operates in constant voltage mode and the output voltage is no longer held constant. Instead,
the power supply will now regulate the output current at its current limit setting. Either a LIM+
4 Using the Regenerative Power System
164 Keysight RP7900 Series Operating and Service Guide