Participants from the IC industry were easy to find both in the exhibition hall and on the conference stage at Strategies in Light. The vendors see a significant market opportunity and are targeting the general illumination market including replacement bulbs, the TV backlight market that's already booming, and other applications such as street lights.
Targeting the backlight market, mSilica demonstrated its MSL3162 display driver IC. The IC can power 16 strings of 10 LEDs for direct-backlight LCD TV designs. Indeed the company exhibited a recently-launched LG TV with the back cover removed and the LED driver circuit boards in full view.
According to the mSilica, typical LCD TVs use six to eight driver boards with each controlling 16 LED strings for direct backlighting. The driver IC must provide the constant current required while also tracking characteristics of the operating LEDs. TV makers can use the monitoring function to prevent overdriving the LEDs thereby maximizing reliability and performance.
NEC Electronics demonstrated microcontroller-enabled drivers for luminaire, entertainment, and street lighting applications. In the case of street lights, the company's HCD/LED MCU can drive four LED channels. Moreover, the microcontroller can handle communication protocols such as Zigbee for wireless applications, and a proprietary power-line communications scheme. The communication capability would allow a municipality to remotely control the lights – for instance dimming the lights to conserve energy.
For lighting applications, NEC demonstrated the 78K0/Ix2 microcontroller that includes TRIAC dimmer capability. The integrated microcontroller also implements power factor correction (PFC) in the AC/DC power converter.
Marvell also sees microcontrollers as a key value add feature in their LED-targeted products. The company demonstrated a T8 fluorescent bulb based on a slim rectangular circuit board with a footprint akin to a pencil. The company's 88EM8080 series of drivers even includes DSP functions that enable PFC in the power converter. The company pledges to enhance the design with integrated wireless communications going forward.
|National Semiconductor LM3424|
Supertex introduced the HV9963 driver IC for DC/DC applications such as backlighting and general lighting. The IC supports PWM dimming and has built-in protection for short- and open-circuit conditions in the LED string.
On workshop day prior to the start of the conference, National Semiconductor presented a half-day educational program focused on driving LEDs. Topics included TRIAC dimming, control techniques, and AC/DC converter design. You can find much of that information on the LED Lighting section of the National Semiconductor web site.