Local Operation
Constant Voltage Mode Operation
If the output is enabled and the configured current set point is much higher than the requirements for the attached load, then the voltage will rise until it reaches the voltage set point. When the output voltage reaches the voltage set point, it stops rising. The unit will continue to operate in CV mode. The load current will still vary to meet any changes in required load current draw resulting from a change in the attached load.
Constant Current Mode Operation
If the output is enabled, the voltage and current start to rise. At this time the unit is operating in CV mode (default operational mode). As the load current drawn reaches the value of the output current setting, the unit will switch to CC mode and not allow any additional current to be drawn above the value of ISET. The unit is now operating in CC mode. The voltage will still vary to meet any changes in required output voltage resulting from a change in the attached load.
Automatic Mode Crossover
Mode crossover occurs when the unit makes the switch between operating modes. Crossover can occur from CV to CC or vice versa, depending on how the attached load resistance changes. Figure
For example, if the unit was initially operating in CV mode with the output voltage at the voltage set point and the load current below the ISET and the attached load resistance began to decrease, the current would rise to meet this change in the load. The load current will increase in proportion to the decrease in the load resistance until the load current drawn reaches the current set point. At this point further decreases in load resistance (increased load current requirements) will cause the unit to cross over into CC mode where the output voltage will vary with changing load resistance and the load current will remain at the ISET value.
The reverse operating mode change can also occur if the load resistance is increased to the point that the required load current drops below the ISET value. At that point the power supply would crossover to CV mode and the load current would be free to vary as the load resistance changed.
