Dialog Semiconductor's iW3640 LED driver IC eliminates the cost of an external MCU and a dedicated power supply.

Component makers direct efforts toward integration to enhance product features while realizing BOM savings.

Smart lighting is the next frontier for LED driver ICs, which are going to play a vital role in helping bulb manufacturers improve product performance and life span while lowering costs. For this, component suppliers such as Dialog Semiconductor plc are actively pursuing Ledotron-based solutions. Ledotron (IEC 62756-1) is the latest digital dimming standard.

Intelligent illumination encompasses solid state lighting or SSL control, which also includes various modes of wired digital dimming via the AC supply line. Toggle-switch brightness adjustment is an example. The technology extends to wireless control using Bluetooth, ZigBee, Z-Wave and Wi-Fi. In addition to bulb brightness, smart lighting systems can also support advanced features such as LED color mixing for warm dimming and mood lighting.

As with any emerging market, intelligent lighting technology kicked off with a limited number of high-priced niche solutions. The Philips HUE Personal Wireless Lighting is probably the most well-known and publicized one. The initial offerings were largely based on off-the-shelf components, according to Scott Brown, marketing divisional director of Dialog Semiconductor’s power conversion business group. “However, as the LED smart lighting market takes off, we are beginning to see LED driver ICs, which are now tailored to the specific requirements of this segment,” said Brown. “These new ICs continue to integrate more functions in chips, helping SSL manufacturers drive down costs and bring smart lighting to mass consumer price levels quickly.”

Dialog Semiconductor has joined hands with LED lighting solutions provider Sengled to fast-track the availability of flexible and intelligent driver ICs for intelligent lighting applications. The strategic collaboration will entail the exchange of R&D data, joint development of new product concepts and prototype bulbs, common system level tests and qualification processes for new solutions. “Smart lighting is one of the most important growth segments in LED lighting, with digital dimming and wireless control as the next major steps in creating innovative products,” said Johnson Shen, founder and president of Sengled.

Dialog Semiconductor is proactive in the Ledotron standard as well. The technology overcomes the limitations and system performance degradation associated with traditional phase cut dimmers. It combines manual dimmer control with easy connection to the Internet of Things, and to any building and home automation system. The dimmer and lamps are linked via baseband data modulation around the zero crossings of the AC mains voltage. Dialog Semiconductor has announced the iW6401 chip. Mark Tyndall, the company’s corporate development and strategy vice president and power conversion business group general manager, said the release will be the world’s first LED driver to support the new Ledotron dimming standard.

BOM savings

The integration drive in LED power supplies catering to smart lighting also serves another critical industry agenda: BOM savings. Adding intelligence to lighting systems necessitated the use of MCU and other discrete ICs, Brown said. The market, however, is quickly evolving and LED driver ICs are becoming better suited to interface with wireless transceivers through the incorporation of serial buses and even nonvolatile memory. “As more specialized features are embedded in the LED driver, it becomes possible to eliminate much of the external circuitry, including the MCU, which significantly reduces BOM costs.”

A number of SSL LED drivers with a reduced number of discrete inputs are now coming to the market. Dialog Semiconductor’s iW3640 model, for instance, automatically implements warm dimming in a single IC. Previously, external color mixing control components were required. The device integrates the driver for a second string of LEDs and uses a digital engine to control the transitions. “This eliminates the cost of the external MCU and dedicated power supply required by conventional warm dimming approaches, and reduces the BOM cost for 75 to 150W-equivalent A19 and PAR bulbs, as well as commercial dimmable external lighting ballasts,” Brown said.

Another example is the iW6401 LED driver, which is specifically designed for a number of smart lighting applications such as dimming control via the supply line to support the Ledotron digital dimming standard. “This driver also incorporates an I²C bus to enable seamless integration in almost all forms of digital and wireless networks, including low-energy Bluetooth, ZigBee and Z-Wave, and allow control from smartphones and other mobile devices,” Brown said. “It also incorporates nonvolatile memory for configuration.”

Volume production for the iW6401 LED driver is expected in 1H14. Later this year, Dialog Semiconductor plans to introduce more solutions with higher levels of integration to further reduce the number of discrete components used and BOM costs.