This presentation discusses controlling LEDs to meet customer expectations. It covers:
- The key components of an LED system, including LED modules, drivers, fixtures/housings, and controls, and how compatibility between components is important.
- Different control types for LEDs like phase control, 3-wire control, and low voltage analog and digital options like 0-10V, DALI, and DMX. Proper control selection depends on the application and desired functionality.
- The critical role of LED drivers in determining dimming performance and compatibility with controls. Driver selection impacts whether customer expectations around dimming performance can be met.
1. Controlling LEDs
to Meet Customer Expectations
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of this presentation.
Controlling LEDs to Meet Customer Expectations
AIA/CES HSW /SD Program Number CLED13 (1.0 Learning Units)
Controlling LEDs
to Meet Customer Expectations
4. • Describe the features and benefits of LEDs as a general
illumination light source, and the applications that are best
suited to LEDs
• Explain the components of an LED system and how each of
these components must be compatible with one another to
ensure efficient, effective, and reliable operation
• Compare existing control types and standards to identify the
differences between power line, 3 wire, and low voltage
control (analog and digital)
• Recognize LED drivers as a critical component in LED
lighting systems and identify their important characteristics
Learning Objectives
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5. • LED Features, Benefits, and Challenges
• LED Applications
• Dimming Expectations
• LED System Components
• LED Drivers
• LED Control Options
Agenda
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6. • High Efficiency (up to 150 lumens/watt and improving)
– 20W LED or less can replace a 100W incandescent
• Reduced maintenance costs
– 50,000+ hour lifetime
• Color temperature
– 2700 K to 4500 K and beyond
• Color Rendering
– 90 CRI or higher is available
• Immediate light output
• No UV/IR radiation
• No mercury, no lead
LED Features and Benefits
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7. • System compatibility
– Driver/LED array and driver/control
compatibility are often confusing
• Thermal management
– Heat must be conducted away from
LEDs effectively
• Color consistency
– Color shift in LED light output can
occur over time
– Products with the same color
temperature can look different
• Exaggerated claims
• Total installed cost and first cost
must be evaluated
LED Challenges
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8. • LED technology is maturing rapidly, and products now
exist for replacing any commercial fixture type:
– Architectural Downlights
– Hi-Bay Downlights
– Cove Lights
– Outdoor Lighting
• When selecting a product you must be sure it is a
comparable replacement both in lumen output and
beam pattern
Commercial LED Applications
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9. • LED technology is maturing rapidly, and products now
exist for replacing any residential fixture type:
– Downlights
– Under Cabinet Lights
– Decorative/Accent Lights
– Sconces
• Again, when selecting a product you must be sure it is
a comparable replacement
Residential LED Applications
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10. • LEDs are a versatile light source with
a multitude of control options
• Compatibility issues between
products hinder LED lighting from
becoming an easy application
• LED lighting manufacturers must
consider their control options in the
design phase of their product
• Lighting designers must consider their
control options in their project design
from the very beginning
LED Applications
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11. Dimming:
• Saves energy
• Extends system life
• Enhances ambiance
• Provides space flexibility
• Increases productivity
• Provides safety and comfort
Dimming Expectations
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12. • The dimming expectations
need to be defined by the
designers and the end users
• Some customers expect
dimming to be similar to
incandescent (well below 1%)
• LED products should clearly
specify their dimming
performance as part of their
specifications
Dimming Expecations
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13. There is a difference
between measured and
perceived light levels:
Measured light: the amount of
light as shown on a light
meter
Perceived light: the amount of
light that your eye interprets
due to dilation
For example,
20% measured light
= 44% perceived light
Dimming Expectations
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15. LED dimming problems
encountered commonly
today:
• Flicker
• Shimmer
• Pop-on
• Drop out
• Flicker
• Poor minimum light level
Dimming Expectations
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These problems have been solved with existing
light sources, why accept them with LEDs?
16. LED components:
• For general illumination, LED modules (or “LED engines”)
are available from many companies including Xicato,
Philips, GE, Osram and many others
• These modules are then used within a lamp or a fixture,
both of which are powered by a driver
LED System Components
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LED driver
LED
modules
17. LED System Architecture:
• LED Fixture
• LED Lamp
LED System Components
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Housing
LED module
External Driver
Luminaire (Fixture)
Control
(Dimming or switching)
Control
(Dimming or switching)
Lamp
Integral driver
LED module
18. Integrated LED (LEDi) Lamps:
• LEDi lamps have screw-in bases in order to replace existing
incandescent or CFL screw-in lamps
• Compatibility with existing dimmers is often unknown
• LEDi lamps always have integral drivers
• LEDi lamps have a wide range of lighting output, color, and
dimming performance, and therefore do not always meet
customer expectations. Actual application mock-ups are always
beneficial!
LED System Components
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19. LED Fixtures:
• Many LED fixtures exist, ranging from traditional to unique
LED-specific designs:
• LED fixtures have an LED module mounted within the fixture
housing
• They may have an integral driver or a separate remote-
mounted driver (similar to a ballast or transformer)
• Again, optical and dimming performance can vary widely
LED Technology
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20. • The appropriate driver is
determined by the electrical
specification of the LED
module and the design of
the luminaire
• Two types of LED drivers
exist:
– Constant Current
– Constant Voltage
• Different types of LED
drivers are NOT
interchangeable
LED Drivers
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21. Constant Voltage Output:
• Provides a constant voltage (e.g. 12V or 24V) to the LED
module(s)
• Used when the number of luminaires or length of cove is
variable and all controlled by one driver (usually external)
• As LED loads are added, power increases (the specification
of the driver determines the power limit)
LED Drivers
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Constant Voltage Output
22. Constant Current Output:
• Driver provides a constant current to the LED module
• Applies when there is a single LED module paired with a
single driver (usually within the luminaire)
• The current output of the driver remains the same
regardless of the power of the LED module
LED Drivers
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Constant Current Output
23. Pulse Width Modulation (PWM) Output Dimming Method
• Available for both Constant Current and Constant Voltage
drivers
• PWM dimming cycles the LED on and off (120-1000+ Hz),
reducing the average light output
• Claimed Benefits:
– Provides more precise control for shared parallel loads
– Prevents color shift
LED Drivers
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24. Constant Current Reduction (CCR) Output Dimming Method
• Applicable only for Constant Current drivers
• CCR dimming reduces the current supplied to the LEDs, reducing the light
output
• Claimed Benefits:
– No stroboscopic effects
– Superior performance with long wire runs
– Minimal EMI (electromagnetic interference) produced
– Class 2 UL CCR requirements allow more output voltage than PWM
LED Drivers
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25. If you only remember two things, remember this:
1. The quality and design of the LED Driver
determines the best possible dimming
performance of the fixture or LEDi
2. Compatibility between the dimmer and the driver
determines how well they will deliver the expected
performance and lifetime together
LED Drivers
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26. LED System Architecture:
Housing
LED module
LED Driver
Luminaire (Fixture)
Control
(Dimming or switching)
LED Dimming Control Options
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Control
Options
Lamp
Integral driver
LED module
Control
Options
27. Types of control:
• Phase control
• 3-wire control
• Low voltage control
– Analog
– Digital
LED Dimming Control Options
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28. Two types of phase control (120V, 220V, or 277V):
• Leading Edge/Forward Phase:
– Incandescent
– Magnetic low voltage transformers
• Trailing Edge/Reverse Phase:
– Electronic low voltage transformers
• Confirm that the LED meets the minimum load requirements
of the dimmer and does not exceed the maximum load
because of inrush current and repetitive peak current
• Contact the control and lamp manufacturer to confirm
compatibility
LED Dimming Control Options
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29. Phase Control:
• Typically used to control an LEDi lamp
• Most installed incandescent (forward phase control)
dimmers are not UL listed for LED loads, but forward phase
control dimmers listed for LED loads are now available
• Reverse phase control dimmers can have better
performance, but they require a neutral wire connection
• Dimmers can be wall-mounted or panel based, but
compatibility between dimmer and LED load MUST be
confirmed
LED Dimming Control Options
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Hot
Neutral
Phase Control
Dimmer
LED Lamp with
integral driver
30. 3-Wire Controls:
• 3-wire controls are available for both small and large
systems (dimmers can be wall-mounted or panel based)
• Uses established wiring methods for fluorescent controls
• Separate control and power feed allows for more precise
control and high power quality
LED Dimming Control Options
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Hot
Neutral
Dimmed Hot
Switched Hot
31. Low Voltage Controls:
• Analog
– 0 -10V
• Digital
– DALI or equivalent
Digital Low Voltage
Data System
– DMX-512
LED Dimming Control Options
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32. 0-10 Volt Control (analog):
• Most 0-10V controls follow standard IEC 60929
– States that fixture (driver) sources current, and control sinks it
– Alternate ANSI 0-10V standard is not compatible, and uncommon
• Typically, line-voltage switching is also included with the
control to switch the fixture off
• 0-10V control signals can be made by wallbox dimmers,
panel dimmers, or interfaces
LED Dimming Control Options
0-10V Control
Neutral
Hot
LED Fixture
To next fixture in
control zone
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33. DALI (Digital Addressable lighting Interface) or equivalent
Digital Low Voltage Data System:
LED Dimming Control Options
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• DALI was developed in Europe as
a fluorescent ballast standard
(IEC 60929)
• Allows for individual addressing of
fixtures on two low voltage wires
• Uses digital signals to send
control information to the fixture
• Allows for increased flexibility in
wiring of power and control
34. DMX 512 (digital):
• ANSI Standard (USITT DMX 512-A)
• Protocol used primarily for mixing colors and quickly-varying
color intensity
• Hundreds of channels supported
• Applications: theatrical and color changing effects
• Problematic when used in general illumination due to
complicated wiring and lack of simple integration with
standard building controls
LED Dimming Control Options
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35. • LEDs are an increasingly important light source because of their
long life, efficiency and flexibility and they are being used in every
form of lighting.
• An LED system includes a control, a driver, an LED module and a
fixture or housing. The compatibility between these components
is critical for proper operation in new applications or when
retrofitting with existing controls.
• There are important differences between phase control, 3-wire
and low voltage control types. Application and desired
functionality dictate the proper control type to be used.
• Selection of the proper LED driver is critical to meet the
customer’s expectations of the control system. Dimmable drivers
provide energy savings and the appropriate light levels for the
space décor and function.
Summary
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