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Products Optoelectronics DC/DC LED Kit Make the right choice with online LED selection tool

A new DC/DC LED control demonstration kit, based on the RL78/I1A microcon- troller (MCU) has been released by Rene- sas Electronics. The MCU series consists of five standard products (ASSP) and is designed for lighting applications. A new version of the company's soft-

ware GUI tool is available with the kit. This enables very easy graphical con- figuration of an LED lighting system while also generating pre-compiled C code for the MCUs. It enables programming of the target device using only a USB cable. Using the software tool assists with generating communication protocol stacks for DALI and DMX512 in seconds. The evaluation board included in the kit implements efficient circuits to demonstrate programmable 3-channel LED constant 350 milliampere (mA) cur- rent control in buck converter topology. Using the 16-bit PWM timers running at 64 megahertz (MHz) and set to the dithering function, further improves the average resolution under a nanosecond. The board also provides a number of dedicated analogue peripherals inte- grated on the chip, such as a program- mable gain amplifier and comparators. Renesas Electronics Europe Enter 202

An online selection tool for quick location of the best power supply reference design for LED lighting applications has been launched by Power Integrations.

Starting with basic decisions such as application and power level, it enables users to see the

filtered results quickly and clearly. For example, the new tool simpli- fies the process of screening mul- tiple designs while evaluating the effect of isolated vs. non-isolated topology or power range. The guide allows engineers to enter selection criteria and drill down to the best choice from the company’s library of reference designs for LED lighting. It lists designs according to three major areas of application: residential, commercial, and industrial. For each list, users can sort data and filter results using different parameters.

Andrew Smith, Product Marketing Manager at Power Integrations said: “The LED Design Selector is ideal for light- ing designers working to opti- mise their LED driver based on multiple electrical and physical design requirements.

“The tool enables quick identifi- cation of the best design approach and option trade-offs.”

The tool is available for trial at: tions/led-driver-ics/led-design- selector. Power Integrations Enter 203

Single-string white LED driver IC for LCD screens

A new single-output white LED driver IC has been developed by Allegro Micro Systems Europe. The device is designed for backlighting applications in LCD displays for automotive and consumer applications. The chip integrates a current- mode boost converter with an

Industrial grade TFT LCD display

A new industrial TFT LCD display introduced by Sharp, is designed for an expanded ambient tempera- ture range from -15° C to 75° C. It can withstand higher mechan- ical loads caused by impacts and vibrations with a backlight operation life of 50,000 hours. The display has a brightness of 800cd/m

2 enabled by a strong

LED backlight so the display can be easily read even at very bright ambient light.

The brightness can be adapted to changing light conditions.


This is important for high bright- ness displays, because the maxi- mum brightness is normally only required for a short time. In poor lighting conditions displays can encounter glare or interfering reflections; the ability to dim displays according to light conditions is extremely benefi- cial for many applications to address these issues. This is nor- mally achieved through pulse width modulation, which is con- trolled by ambient light sensors. The brilliant image reproduc- tion of the LQ121S1DC71 is based on the SVGA resolution with 800 by 600 pixels and 260,000 colours, high static contrast of 800:1 and the large viewing angle of 160° h/v. Sharp Microelectronics Europe Enter 205

internal power switch and one current sink for applications such as automotive infotain- ment, cluster and centre-stack lighting, industrial LCD displays, portable DVD players, flatbed scanners, and LED lighting. The A8513 can operate from a single power supply from 4.5 to 40V to accommodate start/stop, cold-crank and load- dump requirements.

The 2MHz switching fre- quency of the boost converter allows the device to operate above the AM radio band. The new device features robust FMEA (failure modes &

effects analysis) performance, and constantly monitors the state of the system to determine if any fault conditions occur with a fault flag pin, alerting the controller to fault conditions. If required, the fault flag can be used as part of a circuit to drive an external p-type FET to disconnect the input supply from the system in the event of a fault.

Built-in protection is provided against a variety of potential problems such as output short- circuit and overvoltage. Allegro MicroSystems Europe Enter 204

Light up with LED power supplies

Two new families of LED lighting power supplies have been developed by Excelsys Technologies. The LDB75 and LDB100 constant voltage/current LED power sup- plies deliver up to 75W and 96W output power respectively, in compact packages. The Xled products are low profile LED drivers delivering constant voltage single outputs of 24V, 36V or 48V. Both operate as constant-current drivers delivering the maximum output current range over the defined voltage range. Standard features of the LDB75 and

LDB100 include: universal input voltage 90-305VAC, constant voltage/current mode operation, high efficiency up to 91 percent, power factor typical of 0.95, wa- terproof to IP67, operating temperature range of -30 to 50°C, Class 2 device (UL1310) with LDB75 also Class II rated. The range offers comprehensive protec- tion to over-current, over-voltage, short- circuit and over temperature operation. Typical applications for the new devices include in-store food display and mood lighting applications, outdoor signs, flat and wide screen street advertising displays, in-store media channels in retail shops, including hypermarts, supermar- kets and convenience stores, high bay lighting for conference centres, hospitality industry and general industrial and retail building architectural lighting solutions. Excelsys Technologies Enter 206

MARCH 2012 Electronics

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