The form factors of the most common fixture types in architectural and commercial lighting saw slight change. Overall, there was still an ease of standard form replacement and upgrading of fixtures that sustained a competitive market and ensured that customers are not dependent on a single source of supply.
Now, the dam is breaking and the lighting equipment market is entering a new era of miniaturization that's fueled by a combination of aesthetic, technological and financial forces.
Miniaturization has a powerful impact on the LED driver since it’s one of the bulkiest components in almost every type of architectural or commercial fixture. A sophisticated, multi-function, high-performance driver supplied by eldoLED contains more components than a TV. This array of components underpins features which lighting designers, specifiers and users highly value.
Now, the ultimate question—how far can LED driver companies take miniaturization without sacrificing core values such as Quality of Light, reliability and efficiency?
The Forces Driving LED Miniaturization
Sleeker, thinner, lighter is a sustained design trend in home and consumer devices. You can see it in mobile phones, in TVs and in laptop computers. The underlying philosophy is to bring the useful function to the fore and to minimize the mechanical structure that embeds the functional elements Today’s TV and phone designs clearly demonstrate that consumers want more screen and less bezel.
Fig. 1: A contemporary commercial lighting design that uses ultra-thin and light luminaires to illuminate without drawing attention to the light source
Aesthetics And Space Allotment
This same philosophy underpins design choices in indoor lighting. Today’s schemes aim to illuminate without drawing attention to the source of the illumination unless the fixture is a decorative object (see Figure 1). This aesthetic principle drives demand for ultra-thin troffers and linear fixtures for small-diameter downlights (see Figure 2).
This new generation of thinner, lighter fixtures is now specified into architects’ plans. The less vertical space required by lighting systems, the more floors that can be squeezed into a multi-story building—yielding a larger lettable floor space.
Fig. 2: The AX2 from Aculux, a 2-inch round LED downlight for commercial applications
Since the LED driver is one of the largest components in most fixtures, reducing the size of the fixture depends on reducing the size of the driver. Advances in semiconductor manufacturing and phosphor technologies yielded significant improvements in LED efficacies—which require less power to generate the same amount of light. Thus, enabling smaller LED drivers. Light sources typically used into today’s indoor fixtures are expected to produce as much as 160lm/W. This increased efficacy means that less power is required to produce a given amount of illumination. In the past decade, the typical power rating of the LED driver in a commercial downlight fell from the typical 30W to 15W.
Semiconductor technology also promises to enable LED driver manufacturers to further shrink their products. Driver companies exhausted the scope for miniaturization using silicon components to convert high-voltage AC mains power to the low-voltage DC required by LEDs. The greatest potential for dramatic reductions in driver size is now in different semiconductor materials: silicon carbide (SiC) and gallium nitride (GaN). As driver manufacturers master the techniques for implementing SiC and GaN semiconductor components, we can expect to see the pace of miniaturization accelerate.
Manufacturers are intensifying their efforts to reduce costs in the more price-sensitive sectors of the lighting equipment market . Miniaturization is one of the keys to unlocking cost savings. The smaller a fixture, the less material required to produce each unit—resulting in lower material costs. A smaller fixture also requires less packaging. The more packed on a crate lowers the shipping costs. Driver manufacturers are under increasing pressure to support this cost-driven miniaturization by reducing the size of their products.
How To Not Miniaturize An LED Driver
In combination, these forces can produce dramatic changes in market demand. The most striking is in the commercial downlight market. The new sleeker design of ‘pinhole’ downlight has a smaller aperture into the ceiling void. The driver must be removable, replaceable and small enough to fit through the aperture. The traditional form factors of 30W or 50W LED drivers are too large.
The most obvious way to shrink the driver is to eliminate components. However, the components in a high-performance LED driver—such as our SOLOdrive or ECOdrive products—are there for a reason. They provide features such as a 0-10V, DALI or LEDcode control interface which designers, specifiers and users highly value.
Complex Circuitry Affects Miniaturization (And Driver Lifetime)
Other aspects of a high-performance driver also call for complex circuitry. The multi-stage power conversion topologies we employ result in higher efficiency and higher power factor compared to other drivers. Higher efficiency in turn affects reliability and lifetime—the more efficient a driver, the less wasted heat it generates and the cooler the driver runs. Since lifetime roughly doubles for every 10°C drop in operating temperature, efficiency directly affects the lifetime of the luminaire.
Complex circuitry also optimizes the way power is delivered to LEDs—helping fixture manufacturers to guarantee the highest Quality of Light. This is reflected in the features we and the lighting design community prioritize: flicker-safe, smooth dimming and Dim to Dark capabilities.
Additional Influencers: Total Harmonic Distortion And Current Ripple
Driver characteristics such as total harmonic distortion (THD) and current ripple also have a perceptible effect on the user’s perception of a fixture’s light output. If miniaturization is taken too far, it can produce visible flicker, restrict the driver operating temperature range, generate excessive electrical noise and cause premature failure.
Eliminating blocks of circuitry would undermine the value which customers derive from high-quality LED drivers.
Figure 3: exploded view of eldoLED DC2DC LED driver in a Stucchi Multisystem
Balancing Miniaturization And Performance
Our response to the industry’s demand for miniaturization is to capitalize on technological advances while making no compromises on performance, reliability or functionality. This means that new driver models in smaller form factors will maintain the same quality as larger, existing models.
An early instance of this approach was the development of the new, low-profile ‘U’ form factor for linear drivers. These 30mm-wide drivers are supplied in a standard ‘L’ form factor which is 26mm high. The ‘U’ models have a lower 21mm profile suitable for the thinner linear lighting fixtures favored particularly in the European market.
New eldoLED LED Drivers On The Horizon
There’s even more scope to produce drivers in new form factors because of the reduced power requirements of today’s more efficient LEDs. In 2022, we'll release ECOdrive and SOLOdrive models with new, lower power ratings of 22W, 12W and 7W. The reduced power capability enables us to dramatically reduce the driver’s size down the so called ‘butterstick’ format (90mm x 33mm x 25.4mm). This is compatible with the ceiling aperture used by the latest generation of 2” downlights.
These drivers will be available in versions with a 0-10V, DALI or LEDcode control interface with the capability to dim to 1% or 0.1%. Efficiency, power factor, THD and other specifications are similar to those of the larger ECOdrive and SOLOdrive models.
Miniaturized Drivers For Space-Saving Configurations
There’s another way to achieve extreme space savings—but it entails a different approach to system design and installation.
The installer’s preferred lighting system configuration is with an AC-DC driver integrated with each fixture (see Figure 4). This requires a single power supply cable running to the fixture. In today’s sleek light fixture designs, this cable provides the mechanical support to suspended lighting units—making installation quicker and easier.
Fig. 4: remote driver architectures can enable radical luminaire miniaturization
DC2DC vs. AC-DC LED Drivers
DC2DC drivers operating from a fixed 48V power distribution bus are smaller, lighter and thinner than an AC-DC driver operating from a universal mains voltage input. This prompted some lighting equipment manufacturers to develop ultra-thin fixtures such as ceiling panels based on a remote power supply configuration and slim DC2DC drivers integrated into each fixture.
This configuration calls for a discrete AC-DC power supply unit (PSU) to be mounted remotely—on a wall or in a ceiling void—and a cable carrying 48V DC from the PSU to the DC2DC driver at each fixture. This remote power supply configuration is still relatively rare for two reasons:
There’s limited availability of commercial DC2DC drivers
The remote power supply configuration is less favored by installers since it’s more time-consuming and difficult to install. Additionally, they need to take care of discrete PSU isolation and safety requirements
Fig 5: eldoLED 48V 32W DC2DC LED driver compatible with Stucchi Multisystem and Multisystem EVO
Balance Quality With Space Savings
Through the provision of drivers in a new butterstick form factor and of a range of standard and custom DC2DC drivers, we’re supporting lighting equipment manufacturers’ response to customer demand for miniaturization in lighting. We're committed to preserving the same light quality, control functions, reliability and long lifetime in smaller form factors with the same signature quality of the eldoLED brand.