This article explains the difference between constant voltage (CV) and constant current (CC) LED drivers, and which type applies to the ENTTEC CVC4. The CVC4 is a constant voltage device: it dims CV LED products such as 12V or 24V LED strip, and it is not suitable for constant current fixtures.
What the two terms mean
A constant voltage driver holds its output at a fixed voltage, commonly 5V, 12V, or 24V DC. The connected LED product regulates its own current, usually through current-limiting resistors built into each strip segment.
A constant current driver holds the current fixed, typically at values such as 350mA, 700mA, or 1050mA, and varies its output voltage to suit the LED load. This is used for LEDs that have no built-in current limiting of their own.
Quick comparison
| Feature | Constant voltage | Constant current |
|---|---|---|
| Output | Fixed voltage, current set by the load | Fixed current, voltage adjusts to the load |
| Typical ratings | 5V / 12V / 24V DC | 350mA / 700mA / 1050mA |
| Typical loads | LED strip, LED neon flex, CV LED modules | High-power LEDs, spotlights, downlights, panel and street lighting |
| Wiring | Loads wired in parallel; strip can be cut to length | Load must match the driver's current rating; wiring needs more planning |
A practical rule of thumb: if an LED product is labelled DC5V, DC12V, or DC24V, it expects a constant voltage supply. If it is specified in milliamps and forward voltage, it expects a constant current driver.
Why LED strip uses constant voltage
Almost all LED strip is built for constant voltage operation:
- Each cuttable segment includes its own current-limiting resistors, so no external current regulation is needed.
- Segments run safely at their rated voltage without further adjustment.
- CV operation allows strips to be cut, extended, and run in parallel, which keeps installation simple.
Feeding LED strip from a constant current driver is a mistake: the driver will push its output voltage up trying to maintain its set current, which can cause flicker and, in severe cases, damage the strip.
Equally, bare high-power LEDs without built-in resistors must not be connected straight to a 12V or 24V constant voltage source. With nothing limiting the current, they overheat and fail. Those loads belong on a constant current driver.
Where the CVC4 fits
The CVC4 is a 4-channel constant voltage LED dimmer. It sits between a constant voltage DC power supply and your CV LED strip, and dims each channel by PWM (fixed 1kHz) from DMX or PLink data. Key electrical points:
- Input voltage: 12 to 24V DC. The CVC4 passes the supply voltage through to the strip, so the power supply voltage must match the strip's rated voltage.
- Maximum 5A per channel and 20A total per unit, protected by a user-serviceable 20A ATO blade fuse.
- The CVC4 does not regulate current. Do not connect constant current fixtures or bare high-power LEDs to it.
See Calculating the maximum length of LED strip a CVC4 can control to size your strip runs against the 5A per channel limit, and Running CV tape in parallel from a CVC4 for parallel wiring and fusing guidance.
Common mistakes
- Voltage mismatch. A 24V supply on a 12V strip is an overvoltage and can burn the strip out immediately. A 12V supply on a 24V strip gives dim, uneven output. Always match supply voltage to the strip's rated voltage.
- Undersized power supply. If the supply wattage exactly equals the LED load, it runs at full capacity with no headroom, which shortens its life and can cause flicker. Allow a margin of roughly 20 to 30 percent.
- Wrong driver type. Constant current drivers on LED strip, or constant voltage supplies on bare high-power LEDs, both lead to flicker, overheating, or failure, as described above.
Full CVC4 specifications are on the ENTTEC CVC4 product page.