Constant Current vs. Constant Voltage LED Drivers: What Is the Difference?

Selecting the correct LED driver is one of the most important steps when designing or repairing an LED lighting system.

Two terms appear repeatedly when comparing LED power supplies:

Constant Current (CC)

and

Constant Voltage (CV)

Although both types of drivers provide DC power, they regulate the output differently and are designed for different types of LED loads.

Using the wrong type can lead to poor performance, flickering, overheating, incorrect brightness, or damage to the lighting system.

Here is how to understand the difference.

What Is a Constant Voltage LED Driver?

A constant-voltage power supply maintains a fixed output voltage while allowing the load to draw the current it requires within the power supply's rated capacity.

Common voltages include:

• 12V DC

• 24V DC

• 36V DC

• 48V DC

For example, a 24V constant-voltage LED power supply is designed to maintain approximately 24V at its output.

Constant-voltage systems are commonly used with:

• LED strips

• LED modules

• Signage

• Architectural lighting modules

• Electronic equipment with internal current regulation

In these systems, current regulation is normally handled by components within the LED module or load.

What Is a Constant Current LED Driver?

A constant-current LED driver regulates the current delivered to the LEDs.

Instead of simply supplying a fixed voltage such as 24V, the driver is designed to maintain a specified current while its output voltage operates within an allowable range.

Common current ratings can include values such as:

• 350mA

• 500mA

• 700mA

• 1050mA

• 1400mA

The correct current depends on the LED or luminaire design.

Constant-current drivers are widely used in professional LED luminaires where the LED array requires precise current control.

Why LEDs Often Need Current Regulation

LEDs are semiconductor devices and their electrical behavior differs from conventional resistive loads.

A relatively small change in voltage can result in a significant change in current.

For this reason, many high-performance LED systems are designed around controlled current.

The LED manufacturer's specifications should identify the appropriate operating current and forward-voltage range.

Example: Constant Voltage System

Suppose an LED strip is designed for:

24V DC

In this case, you would normally select a 24V constant-voltage power supply with enough current capacity for the total LED load.

If the complete LED installation requires 200W:

200W ÷ 24V ≈ 8.33A

The selected power supply must therefore provide enough current and wattage for the complete system while also meeting the manufacturer's application and derating requirements.

Example: Constant Current System

Consider an LED module designed to operate at:

1400mA

with a defined forward-voltage range.

Instead of selecting a power supply based solely on a fixed output voltage, you would search for a constant-current driver capable of delivering approximately 1400mA while supporting the required LED forward voltage and total wattage.

Can You Use a Constant Voltage Driver Instead of Constant Current?

Not automatically.

If an LED system was engineered for a constant-current driver, replacing it with a standard constant-voltage power supply may cause improper operation.

Similarly, a constant-current driver should not automatically be substituted for a system designed around a fixed-voltage LED module.

The electrical design of the load determines which type is appropriate.

What About Dimming?

Dimming adds another requirement to LED driver selection.

Depending on the MEAN WELL product family and model, dimming options may include:

• 0–10V

• PWM

• Resistance

• DALI

• Other control methods

Not every driver provides the same dimming functionality.

Before purchasing a replacement driver, identify both the electrical requirements of the LEDs and the control method used by the lighting system.

Other Specifications to Check

In addition to CC versus CV, consider:

Wattage

Make sure the driver can support the required LED load.

Input Voltage

Confirm compatibility with the available AC supply.

IP Rating

Outdoor and wet-location applications may require additional environmental protection.

Operating Temperature

Temperature can affect the amount of power a driver can safely deliver.

Dimming

Confirm that the driver's dimming interface is compatible with the lighting control system.

Certifications

Check the exact model's current safety and regulatory documentation when the project requires specific approvals.

MEAN WELL LED Driver Families

MEAN WELL manufactures multiple families of LED drivers for different lighting requirements.

Common series include:

• XLG

• HLG

• ELG

• NPF

• PWM

• LPV

• LCM

Each series is designed around different combinations of wattage, output characteristics, environmental protection, dimming, and application requirements.

Need Help Finding the Correct LED Driver?

If you are replacing an existing LED driver, send HTD Electronics:

• Existing model number

• Input voltage

• Output voltage

• Output current

• Wattage

• LED type

• Number of LEDs or luminaires

• Dimming method

• Indoor or outdoor application

Our team can help determine which MEAN WELL product family best matches the application.

Shop MEAN WELL LED drivers at HTD Electronics with U.S. inventory, technical support, fast order processing, and volume pricing.