Constant Current (CC) mode is an operational mode where the power supply maintains a constant output current regardless of changes in the load's resistance. To operate in CC mode, you must set the power supply's current limit to your desired value and its voltage limit to a value higher than the voltage the load will require at that current. This required voltage can be calculated using Ohm's Law (Voltage = Current × Resistance).
For example, to supply 2A to a 5Ω resistive load:
1. The voltage required by the load is 10V (2A × 5Ω).
2. Set the power supply's current limit to 2A and its voltage limit to any value greater than 10V.
3. The power supply will now operate in CC mode, providing a stable 2A current, while the output voltage automatically settles at 10V.
If you then lower the voltage limit below 10V (e.g., to 8V), the power supply will switch to Constant Voltage (CV) mode. It will output 8V, and the current will drop to 1.6A (8V / 5Ω), as it is now limited by the voltage setting.
Warning: If the output is enabled with no load connected (an open circuit), the output voltage will rise to the set voltage limit. Connecting a load under this condition can cause a sudden surge of current or voltage, potentially damaging the load. To prevent this, always connect the load *before* enabling the power supply's output.
Note: When working with any load, it is crucial to set voltage and current limits that are within the load's safe operating area (SOA). Consider the load's power rating, thermal capacity, and other specifications. As a best practice, start with low voltage and current settings and gradually increase them to the desired level while monitoring the system to ensure safe operation.
Main applications of constant current (CC) mode
- Light-emitting diodes (LED)
- Laser diodes (LD)
- Battery charging
- Plating
- Electrochemical processes (e.g., electrolysis, plating)