Suppose we have the same Lumileds LED mentioned above. Characteristic curves reveal the LED should carry about mA to produce its rated light output and it should operate with a forward voltage of 6. For the sake of simplicity, assume the circuit contains only one Lumileds LED. Further suppose we use a V supply.
Thus the power dissipated in the resistor is 3. But the power dissipated in the LED is 6. So the combination dissipates 6. And it gets worse. Another drawback of a series resistance is an inability to closely control the current.
LED forward voltage can vary from one unit to the next, so the voltage drop across any resistor put in series with the LED will vary as well. Thus as current can vary from one LED to another, so too will the light output. The drawbacks become more apparent when multiple LEDs are involved.
In the example of the V supply, the LEDs would necessarily be powered in parallel with power dissipated in multiple resistors and light output varying from one LED to another. All these difficulties make it more feasible to drive LEDs with a constant-current power supply rather than a current-limiting resistor with a constant-voltage source. Again for reasons of energy efficiency, switch-mode power supplies are the topology of choice rather than linear supplies.
The problem with linear supplies is that they all contain a variable-resistance pass element i. Depending on the type of LED driver you select, their dimming skill can cover the full range. The driver dims the LEDs by either shortening the amount of leading current going through it, or by a method called pulse width modulation PWM.
Most drivers that offer dimming use PWM. This allows dimming without flickering and with usually very little color change in the LEDs. It is good to note that dimming does not affect an LED's competence. It also will not have a negative impact on how long it lasts. In fact, dimming can potentially help LEDs last longer as it will reduce the heat it creates when lit.
Rather, it uses different colors that when shown together produce white light. So with a driver with this capability, you would be able to control the different colors of LEDs in the product to create a full rainbow of colors depending on which are on and which are off. The store will not work correctly in the case when cookies are disabled. Request Call For Price. Request quote.
LED Driver: What is it and how does it work? Knowledge Base Search. Twitter: ShineRetrofits. Tweets by shineretrofits. Thank You! Recent Posts. Cancel Continue Shopping. Add To Cart Please wait Go To Checkout. Max Wattage. For example, if your external driver can operate a maximum of watts, it should only operate LED light bulbs that use 96 watts. All three types of external drivers offer dimming capabilities.
Be sure that both the LED lightbulb and the driver indicate that they have dimmable functions on the product data sheet. Most dimmable external drivers will require an external lighting control system.
These devices will specify what external dimmer is needed to control certain LED bulbs. Learn how to Install dimmers and sensors with our Lighting Control Guide. Class I vs. Class II. This means that the power output is safe for contact and no major safety protection is required for handling.
There is NO risk of fire or electric shock. These drivers can operate with:. Due to their high voltage output, Class I drivers require safety protection when handling them. Unlike their counterpart, Class I drivers are far more efficient because they can accommodate more LED light bulbs. We strive to provide quality products at competitive prices.
Whether you are looking to replace or retrofit your lighting system, we can help you along the way. Shop for LED Lighting. Stay Connected. Like this Blog?
0コメント