Page 39

EETE APR 2014

Alternatively, electro-active polymers could be used to implement micro-actuators. But once the concept proven, what sort of resolution would you get and would that be enough for basic obstacle avoidance? “We aim to get a physical resolution of 100 pixels at the contact lens level. This after proper encoding in the camera will be equivalent to 1000 pixels resolution at the object plane” explains Zalevsky. “Therefore in order to improve the spatial resolution we intend to use time multiplexing, aiming to improve the resolution by Fig. 3: I C Touch’s haptic lens prototypes with thin electronics sandwiched between soft lenses. Mid-power LEDs claims unmatched lumen density Seoul Semiconductor has released a generation of LEDs that the company claims deliver industry leading performance and lumen density in the mid-power class. The mid-power product family of the Acrich MJT 2525 series offers a compact symmetrical package with dimensions of 2.5x2.5 mm and wide beam angles making these LEDs ideal for applications that require uniform illumination. The Acrich MJT 2525 series is a compact high voltage mid-power package with a typical forward voltage of 22 V. At 3000 K and a CRI of 80 it achieves a brightness of 95 lumens and an efficacy of 105 lm/W at an operating current of 40 mA at 25°C. With a lumen density of 15 lm/mm2 this midpower package is best in class and has a lumen density five times that of any other midpower package making it ideal for space constrained lighting applications. The wide viewing angle on these LEDs also helps implement the omni-directionality in replacement lamp designs. The high voltage Acrich MJT 2525 series incorporates the Acrich- Multi-junction Technology with multiple LED driver reduces dimmable MR16 LED lamp footprint Diodes Incorporated has introduced DC-DC converter with boost, buck and voltage-inverting modes that fits in a compact DFN6040-12 dual exposed-pad package which enables a reduction in form factor of MR16 LED lamp circuits. The AL8812 co-packages a 60 V, 3.6 A-rated power N-channel MOSFET with all primary functions required by a DC-DC controller. With a 6 mm x 4 mm footprint and an off-board profile of 0.6 mm, the AL8812 converter is comprised of a temperature-compensated reference, comparator, controlled duty cycle oscillator with active current limit circuit, driver and high current output switch. The AL8812 has an input voltage range of 3 V to 20 V and an output voltage that is fully adjustable up to 60 V. The wide operating voltage range makes the device suitable for medium-voltage LEDs and 12 VAC lighting applications, as well as dimmable MR16 LED lamps. Shut-down current is low at less than 0.01 μA, typical, and its maximum output switch current is 3.6 A. The converter is able to deliver very accurate voltage and current control by incorporating a precision reference with a 2% tolerance. By combining the AL8812 with its AL8807A constant almost another order of magnitude in each axis to produce a final image resolution of around 10,000 pixels, as close to one million”. I C Touch thinks its findings could benefit visually impaired people but could also lead to new augmented reality applications, converting particular situational information into tactile feedback. In the future, the company aims to license the concept to third party manufacturers. junctions on a single monolithic chip eliminating the usage of multiple wire bonds between several die’s to the high voltage architecture. The construction improves the reliability of the LED package since it reduces the potential number of failure modes associated with wire bonds within the LED package. The high voltage architecture also enables the use of simpler, more cost-efficient drivers, compared to conventional LEDs. The improved efficiency of the driver electronics also results in less heat generated and fewer electronic components used in the driver design allowing more space for thermal management within the luminare. “The new 2525 Series has unparalleled lumen density in the mid-power class of LEDs not only reducing the total system costs for designers but also enabling new possibilities in lighting design,” explained Jay Kim, Seoul Semiconductor Executive Vice President of Lighting sales division. “The MJT 2525 series has higher cost efficiency than most mid-power packages and has already been adopted worldwide in a number of designs by key customers.” Seoul Semiconductor www.SeoulSemicon.com current step-down converter, Diodes Incorporated has produced a two-stage reference design for dimmable MR16 LED lamps that provides good transformer compatibility and low current ripple at a reasonable BOM cost. The AL8812 universal DC-DC converter is available from Diodes Incorporated for $0.3 each in 3k quantities. Diodes Incorporated www.diodes.com www.electronics-eetimes.com Electronic Engineering Times Europe April 2014 39


EETE APR 2014
To see the actual publication please follow the link above