Solid-State Two-Wire LED Dimmer for Intelligent Control
Article By : Maurizio Di Paolo Emilio
Amber Solutions has introduced a solid-state two-wire dimmer solution that works without a neutral wire...
Amber Solutions has introduced a solid-state two-wire dimmer solution that works without a neutral wire. It is compatible with most lighting and LED technology and it provides an intelligent control and homogeneous dimming with a slim form factor which is 3/4 inch deep.
In an EE Times interview, Thar Casey, CEO at Amber, highlighted how this new two-wire solution allows electrical infrastructures to offer a controlled dimming without additional wiring, thus eliminating the old TRIAC.
In some circumstances, the electrical infrastructure is outdated in older buildings, posing a problem for implementing intelligent systems and limiting the transition towards a full smart home. A topic for an efficient smart home is the smooth zero-percent to max-power dimming capability.
Amber’s 2-Wire Dimmer Switch
Amber’s solid-state redesign incorporates an intelligence that can be adapted to any load situation, offering a flicker-free dimming experience in a slim form factor that fits seamlessly into everyday electrical installations. The flicker phenomenon is defined as the perception of visual instability induced by a light stimulus whose luminance, or spectral distribution, fluctuates over time. Owners and installers of these dimmers can benefit from native overvoltage and short-circuit protection, energy savings through reduced power dissipation, and the option for integrated wireless device control that also enables over-the-air updates for each type of new product via their smartphones.
Problem and Technology
Since the early 1900s, the two-wires configuration has been widely used in everyday electrical infrastructure. In the 2000s, the introduction of energy-efficient solutions and new LED solutions and dimming modes through TRIACs, created quite a few problems due to the neutral wire need.
Most homes do not have a neutral wire system in their light switch electrical boxes, forcing manufacturers to adapt by selecting ad-hoc solutions, often with TRIACs. Unfortunately, the TRIACs struggle to operate without a neutral due to the power required, thus creating affecting the quality of today’s two-wire dimmer switches.
A TRIAC acts as an AC switch, controlled by a small current at the gate terminal. A microcontroller pin can very well generate this current. The problem is that the gate is directly related to the mains and that the ground of the logic part of the circuit must be connected to a mains pole. The result is twofold: the logical area of the circuit is brought to mains voltage, exposing the user to dangers. A direct bridge is formed with everything that passes through the network, i.e. overvoltages and disturbances. This leads to an increased possibility for the microcontroller to malfunction, due to the impulses of the network.
“TRIAC was invented in the late 1950s. It’s a great technology and it is still being used. But the TRIAC technology is bulky, and is older electromechanical architecture. Ours is solid state so it is not electromechanical, which solves a lot of industry issues, such as improving the quality of the dimming experience, reduced size for an easier more flexible installation, and more. So that’s why many companies are eliminating the TRIAC with solid-state solutions like ours,” said Casey.
Current TRIAC technologies are holding back the industry, especially while foreseeing the high minimum power requirements with limited switching capacity and space requirements due to heat dissipation problems. One of the consequences is incompatibility with LEDs that cause brightness problems including ghosting and flicker.
“We are talking with many companies who having a problem right now with their products, which don’t dim well and flicker or they have a drop off at for example 25% or 75%. Or they stay ghosting. Ghosting means the light stays on – even when you are at zero dimming, the light stays on, and you can see the light is still on a little bit. It’s not 100% off. Now, that’s because they’re using a two-wire solution based on the old electro-mechanical architecture. With the two-wire solution, there is no neutral. One wire goes in, one wire goes out. That’s it. There’s no neutral. Many buildings around the world are considered old. And electricity in these buildings does not have a common wire- that white wire, called neutral. Therefore, it’s very difficult to get enough power to products without a neutral, making it a challenge to have good dimming. It’s also very difficult to have Wi-Fi or Bluetooth integrated, because there’s not enough power to power up smart connectivity. We’ve found a solution to power up a light switch dimmer without the neutral. In addition to this, we can program our technology not to flicker and enable a max range for dimming and more. And we even can integrate energy monitoring and metering,” said Casey.
With the advent of LED technology, new possibilities of light control have also led to further considerations on the quality of the light emitted. The inclusion of new lighting technology in systems or products designed around traditional technologies has a common flicker problem. Therefore, this phenomenon occurs when, under static conditions, we perceive that the light does not remain constant over time and tends to shake or flicker. A candle flame represents a typical light source where this phenomenon is clearly visible. Every small air movement tends to move the flame and change the intensity and directionality of the light, generating flickering or unstable light.
The phenomenon is limited to the sensitivity of the human eye, which, according to studies and experiments, depends on light modulation frequency. We can clearly perceive the flicker phenomenon at 10 Hz (maximum sensitivity), while as the frequency increases, it becomes less and less perceptible up to a frequency value around 80 Hz. Beyond these frequencies, the phenomenon is no longer perceived, and this also explains why the flicker in incandescent or discharge lamps is not normally visible.
The dimming performance of LEDs in TRIAC dimmers is one of the greatest challenges in electrical engineering. The problem is that with TRIAC, dimmers are designed to be used with incandescent lamps, which have resistive loads. When you started using LEDs with dimmers, the low current requirements, together with the non-resistive nature of the devices, caused the TRIACs to turn on and off intermittently as the electronics do not provide sufficient current when the Triac turns on, thus causing flicker.
Amber’s intelligent solutions make it possible to manage electricity through MOSFET solutions, thus reducing dissipation and energy consumption problems compared with TRIAC. This solution opens up new opportunities for additional sensor and wireless integration in the smart home field thanks to its small form factor.
He added, “Amber’s technological innovations in digital electricity control through solid-state architecture offers the opportunity to turn enhance the value of 2-wire dimmer switches on the market today. Amber AC/DC Enabler and Amber AC Switch are our two products to offer advantages in terms of electrical efficiency that are not feasible with today’s standard, old-style infrastructure,” said Casey.
Amber Solutions
Amber’s 2-Wire implementation utilizes Amber’s core technologies, transforming 2-wire dimmer products into a new architecture. Casey highlighted how, for example, Amber’s AC Switch™ with Amber’s AC-DC Enabler™ provides high reliability compared
with TRIAC due to its solid-state architecture, eliminating all mechanical parts used in existing solutions and minimizing heat dissipation and energy waste.
Amber’s solid-state construction allows for a flicker-free dimming experience and a minimum power range to eliminate most ghosting, also ensuring greater efficiency in LED applications.
“Looking to the future, our two-wire dimmer architecture will enable 3-way dimming using only one traveling wire, offer intelligent automatic detection of load types, and create a wireless architecture by eliminating the need for wires or batteries in devices such as smart thermostats and smart doorbell cameras,” Said Casey.
Onboard Artificial Intelligence support allows you to recognize the load, offering flexibility to dynamically support trailing edge dimming. Thanks to the small footprint, there’s also plenty of room for third-party manufacturers to add sensors and other smart features inside the electrical boxes.
The great revolution is focused on replacing the TRIACs, which are traditionally useful for bidirectional current control. Amber’s goal is to replace TRIACs with solid-state MOSFET technology with integrated intelligence.
The two-wire dimmer can handle up to 1000 watts of current and is independent of the input voltage, which makes it compatible with any power grid on earth. The almost universal compatibility with LED lighting solutions ensures operability with all electrical infrastructures of the past, present and future.
Casey concluded the interview with an interesting view that can be summarized here: we are always looking for energy, we are dependent on electricity, and electronic design is fundamental to maximize the efficiency, utility, longevity, and intelligence of the tools we use to provide energy to our cities, businesses, homes, and devices. The watchwords for tomorrow’s home are: green and smart, or environment and technology.