With recent advances, LED lighting systems now offer many benefits over incandescent, halogen, and fluorescent lights. As LED lighting continues to proliferate, these systems need to adapt to existing infrastructures and respond to new market dynamics. In industrial applications such as office or theatrical lighting, LED lighting is being adopted for its substantial energy savings. This adoption will continue to push down the system cost which will drive LED lighting systems into the residential market.
To first expand in the industrial market, LED lighting solutions need to interface with existing network protocols such as DALI and DMX512. Specialized MCUs are the best way to handle the communication and control of LEDs. Moreover, as new markets develop with different communication protocols such as ZigBee and powerline communication (PLC), specialized MCUs can be re-programmed quickly to support them.
Such market dynamics are driving LED lighting systems to become more intelligent in handling both light quality and communication functions. To address these needs, NEC Electronics has rolled out two microcontroller lines (Fig. 1). The K0/Ix2 and HCD/LED MCUs both have specialized hardware to support LED lighting systems. In the K0/Ix2 line, the comparator, ADC, and op-amp are interlinked and can be used to perform power factor correction (PFC) or to drive a constant current to the LEDs without MCU supervision. In the HCD/LED MCU, a dedicated four-channel constant current driver is integrated with the MCU. With specialized hardware, this MCU has the bandwidth to handle a wide variety of communication functions and standards ranging from DALI and DMX512 to ZigBee and PLC.
In single-channel LED systems powered by direct AC (Fig, 2/Topology 1), designers can use NEC Electronics’ K0/Ix2 MCU series (uPD78F074x/5x). In a system with a dedicated power subsystem, the same MCUs can also be used in systems with up to three LED channels (Fig. 2/Topology 2). In addition, the K0/Ix2 MCU can help realize boost mode in LED lighting systems.
In systems with multiple channels of LEDs, the HCD/LED MCU (uPD78F8024/25) offers high performance and integration with a dedicated four-channel constant current driver (CCD). The high-current CCD can operate at high switching frequency and high voltage, giving it the flexibility to perform in either boost or buck mode (Fig. 2/Topology 3). With dedicated hardware, these MCUs are freed from monitoring and controlling the LEDs and can therefore perform a variety of lighting functions such as dimming, thermal management, color tuning, and communication. The evaluation kit EV-K0-HCD allows you to demonstrate the MCU’s capabilities and easily develop intelligent code for emerging high-power LED lighting applications.
In addition to MCUs, NEC Electronics offers a selection of compact, low-voltage MOSFETs that are well suited for LED lighting (Fig. 3).
Visit www.SemiconductorStore.com for an NEC Electronics lighting-control development kit and more information about NEC Electronics products for lighting applications. For questions about pricing, availability, or product features related to NEC Electronics microcontrollers, power management, or memory products, contact Symmetry Electronics at (866) 506-8829.
Reprints
