Operation
Power Supply Regulation Modes
Release 3.0 59
Power Supply Regulation Modes
The power supply has 3 regulation modes while in the Normal Operation State:
•Constant Voltage (CV)
•Constant Current (CC)
•Constant Power (CP)
The CV, CC, and CP annunciators indicate the regulation mode.
Constant
Voltage (CV)
In this mode, the supply’s output voltage is constant while the current and power
vary with the load. The power supply will operate in constant voltage mode
whenever the load current IL is less than the current limit setting ISET, or: IL<ISET.
(IL=VSET/RL). In constant voltage mode, the power supply maintains the output
voltage at the selected value (VSET) while the load current IL varies with the load
requirements.
Constant
Current (CC)
In this mode, the supply’s output current is constant while the voltage and power
vary with the load. The power supply will operate in constant current mode
whenever the load resistance is low enough that the load current IL is equal to the
current limit setting ISET. (VL=ISETRL). In constant current mode, the power supply
maintains the output current at the selected value (ISET) while the load voltage VL
varies with the load requirements.
Constant
Power (CP)
In this mode, the supply’s output power is constant while the voltage and current
vary with the load resistance. The power supply will operate in Constant Power
mode when the power drawn by the load is equal to the power setpoint and the
product of the voltage and current setpoint (VSET and ISET) is greater than the power
limit point (PSET). In Constant Power mode, the power supply maintains the output
power at the selected value (PSET) while the load voltage VL and load current IL
varies with the load requirements. The power limit is normally set to the maximum
supply rating, so the Constant Voltage or Constant Current modes will always be in
effect without entering into the Constant Power mode of operation.
Automatic
Mode
Crossover
This feature allows the power supply to automatically switch operating modes in
response to changing load requirements. If, for example, the power supply was
operating in Constant Voltage (CV) Mode (IL < ISET), and the load changed so the
load current (IL) became EQUAL TO the current limit setting (ISET), the power
supply would automatically switch into Constant Current (CC) Mode and the output
voltage would vary in response to changes in load current. If the additional load was
subsequently removed so the load current was again LESS THAN the current limit
setting, the supply would automatically return to Constant Voltage (CV) Mode.