Constant Current vs Constant Voltage LED Drivers
Constant Current (CC)
CC drivers provide a specified fixed current over a range of output voltage. F-Drive CC drivers can be configured to provide between 200–700 mA (default is 200 mA). CC drivers automatically vary the output voltage (within the operable range) to maintain the current output setting. Reducing the drive current reduces the intensity. When you connect multiple CC LED luminaires in series on a single output channel (circuit), the required drive current remains constant while the drive voltage increases proportionally. For example, see the table below.
| Number of 3rd Party 12v CC Luminaires Installed in Series | Drive Current | Total Drive Voltage |
|---|---|---|
| 1 | 700 mA | 12 V |
| 2 | 700 mA | 24 V |
| 3 | 700 mA | 36 V |
Constant Voltage (CV)
CV drivers provide a specified constant voltage over a range of output current. A CV fixture must receive its labeled voltage within a small tolerance, or it will not work. For example, a 24 V CV fixture receiving only 22 V may not turn on. CV drivers employ PWM dimming. Systems with CV fixtures must factor in voltage drop, the decrease in voltage over the length of the cable run (line loss). Traditionally, voltage drop is minimized by installing short runs of wiring. F-Drive allows thicker gauge wire and compensates for line loss.