An LED is simply a diode that emits light when a current flows through it. LED light intensity is directly related to the current. Because an LED has virtually no resistance, some means of current control is necessary or it will burn out. The simplest method is a current-limiting resistor. This is common for low-power LED lights intended for use with batteries.
However, this is impractical for high-power LED circuits designed for mains operation. Because LED light output is proportional to the current, it’s possible to dim LED lights, provided that the dimming system used is compatible with the LED driver, excellent LED dimming performance is achievable.
LED Dimming Methods
The type of dimming method used is determined by the LED driver characteristics. Some drivers are designed to be compatible with the conventional phase control systems used with incandescent lamps. Due to the inherent characteristics of the LED driver, reverse phase control systems are the most common method as this prevents damaging current surges as the power is applied.
For various reasons, this form of dimming does not always provide smooth, predictable dimming. For increased dimming performance, many LED driver suppliers specify a separate low-voltage dimmer control that sends a signal to the driver to regulate dimming.
Primary Benefits of LED Dimming
Apart from the ability to reduce the level of light, LED dimming systems have three key benefits:
- Enhance ambiance: A LED dimmer allows you to control the amount of light you need. A bright light is best when working or performing tasks when you’re active, while a less intense light helps you to relax.
- Energy efficiency: Because light intensity is directly related to LED current, dimming the lights saves energy.
- Extend lamp life: LED lamps run cooler when dimmed. This also significantly extends the life of both the LED lamp and LED driver.
Matching a Dimming Driver
When selecting an LED driver for dimming, you mustÊbe careful to ensure the dimmer, driver and LED are compatible:
- Dimming method: Verify that you install a dimmer that is compatible with the driver you are using.
- LED suitability: Ensure the LED can be dimmed. This is particularly important for LEDs supplied with an LED driver.
- Driver quality: Avoid cheap, no-name brands of LED drivers, since you cannot verify their performance.
- Compatibility: Ensure that the dimming driver you select is compatible with the type of LED luminaire you have selected.
Key Aspects of LED Dimming Performance
It’s crucial to evaluate the level of performance required for each LED driver dimming application. Points to watch out for include:
- Flicker: Unwanted flickering is distracting and should not be tolerated.
- Turn-off ratio: Make certain the dimming range of your LED driver is suitable as some drivers don’t completely turn off.
- Smooth dimming characteristic: The dimming process should be smooth and linear. There should be no reason for lamps to suddenly turn on or off.
- Memory: If it’s important the LED dimmer remembers the last setting, ensure the driver has this capability.
When selecting LED drivers, be aware that the industry is poorly regulated and there is significant variation in LED dimming performance. Not every LED and LED driver is the same or even compatible.
For critical applications, it’s best to deal only with well-known reputable suppliers. One way to establish if a supplier is reputable is to ask for data sheets and compatibility charts. If these aren’t available or you are told that the driver is compatible with any LED, walk away because this is simply not true.
To ensure you select the right dimmable driver, contact us at ERP power. Our comprehensive range of dimmable drivers is compatible with LEDs from all major manufacturers.