Installing LED lighting, choose constant current or constant voltage LED driver?

This article discusses two ways to drive LED lighting: constant current driver and constant voltage driver. Which driver to choose depends on the application requirements. Constant current drivers are suitable for large-scale applications, while constant voltage drivers are suitable for cost-sensitive scenarios that require flexible adjustment of the number of LEDs.

Constant current or constant voltage LED driver: Which is better for you?

If you have decided to install LED lighting, you may have noticed that there are multiple ways to power it. One of the biggest decisions is whether to use a constant current driver or a constant voltage driver. In some cases, both can work, but each has advantages and disadvantages.

Constant voltage driver Constant voltage drivers work by providing a fixed voltage to the LEDs. It maintains the overall power level by adjusting the current output. If your LEDs or LED strips are clearly marked for a specific voltage, then a constant voltage driver may be your best choice. Constant voltage drivers are usually available in 12V or 24V specifications. Constant voltage drivers are relatively cheaper than constant current drivers because they require fewer components. In addition, constant voltage drivers are also easier when replacing LEDs. You can add or remove LEDs as needed, and as long as the voltage requirements remain the same, the driver should be able to increase or decrease the current to accommodate the new setup (assuming the current requirements of all LEDs are within the range of the driver). When using them, your LEDs need to have built-in over-current protection (OCP).

With constant-voltage drivers, if the voltage requirements change slightly (such as when the temperature changes), the current can change significantly to maintain the same power level. This can easily exceed the current limit of the LED, causing light output fluctuations, shortened life, or even outright damage to the LED. Therefore, it is very important to have OCP on the LED. If your LEDs are designed with this in mind, it is safe to use constant-voltage drivers.

Constant-current drivers

Constant-current drivers work by providing a fixed current to the LEDs. It maintains the overall power level by adjusting the voltage output. Although it is easier to precisely control the current output than the voltage output, it requires more components and is therefore usually more expensive. However, when using constant-current drivers, the LEDs will generally have more stable light output, higher reliability, and better efficiency. The downside is that constant-current drivers are more cumbersome when making lighting changes. Changing the number of LEDs will naturally change the current requirements of the system, which may cause the driver to increase the voltage to a level that is unsafe for the LEDs, so the driver will need to be adjusted or replaced according to the new current requirements.

Constant current drivers are a good choice in most large-scale applications, especially in terms of power usage and maintenance costs. If your LEDs do not have built-in overcurrent protection, you will need to use a constant current driver.

All LEDs that require constant current should list the current requirements as well as the voltage range they can accept to avoid damage. Make sure the driver you choose meets the current requirements and that the voltage output is within the specified range of the LED to prevent overdriving the LED.

In short:

Constant current drivers are more efficient and less likely to damage your LED investment, but are more tedious to adjust in the system. Constant voltage drivers are less expensive and easier to adjust for the number of LEDs, but are more likely to cause damage to the LEDs, use more energy, and require the LEDs to have built-in overcurrent protection. Which one to choose depends on the needs of your application.