Linear LED controllers do not require inductors for signage and smart-lighting

Diodes offers the AL5814, AL5817, AL5815 and AL5816 linear LED controllers, claimed to deliver dimmable and adjustable drive current for LED strings with more than 80 per cent efficiency. The AL58xx series provides a low bill of materials cost for a range of applications in the commercial and industrial areas including signage, instrumentation illumination, lighting of appliance interiors, architectural details and general smart-lighting installations.

Input range is 4.5 to 60V. The AL5814, AL5817, AL5815 and AL5816 linear LED controllers do not require inductors and maintain good EMI performance, making system integration simpler. Internal power dissipation is also minimised compared with other designs due to an external power transistor, says Diodes. The AL58xx series is capable of providing up to 15mA to an external MOSFET or bipolar transistor to drive LED strings. The LED drive current is configured by an external resistor with four per cent reference voltage accuracy and excellent temperature stability. In addition, the AL5815 and AL5816 devices support PWM diming, while the AL5814 and AL5817 devices support both analogue and pulse width modulation (PWM) dimming.

Protection features include over-temperature and input under-voltage lock-out. The AL5814 and AL5817 devices also provide ‘LED open’ protection via a Vfault pin, as well as LED thermal fold-back protection.

The linear controllers exhibits good EMI performance and the wide temperature range of -40 to +105 degree C enables the parts to also operate in harsh environments.

The AL58xx series is available in SOT-25 and thermally-enhanced MSOP-8EP packages. 

Diodes manufactures and supplies application specific standard products within the broad discrete, logic, analogue and mixed-signal semiconductor markets. Diodes serves the consumer electronics, computing, communications, industrial, and automotive markets.

The company’s portfolio includes diodes, rectifiers, transistors, MOSFETs, protection devices, function-specific arrays, single gate logic, amplifiers and comparators, Hall-effect and temperature sensors, power management devices, including LED drivers, AC/DC converters and controllers, DC/DC switching and linear voltage regulators, and voltage references along with special function devices, such as USB power switches, load switches, voltage supervisors, and motor controllers. Diodes also has timing, connectivity, switching, and signal integrity solutions for high-speed signals.

Corporate headquarters and Americas’ sales office are located in Plano, Texas and Milpitas, California, USA. Design, marketing, and engineering centres are located in Plano, Milpitas, Taipei, Taoyuan City, and Zhubei City, Taiwan; Manchester, England; and Neuhaus, Germany.

Diodes’ wafer fabrication facility is located in Manchester, with an additional facility located in Shanghai, China. Diodes has assembly and test facilities located in Shanghai, Jinan, Chengdu, and Yangzhou, China, as well as in Hong Kong, Neuhaus and Taipei.

http://www.diodes.com

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Software brings Amazon Alexa to connected objects

The X-Cube-AVS software package from STMicroelectronics enables Amazon’s Alexa Voice Service (AVS) to run on STM32 microcontrollers This means, simple connected objects such as smart appliances, home-automation devices, and office products, can support advanced conversational user interfaces with Cloud-based intelligence like automatic speech recognition and natural-language understanding.

The expansion package for the STM32Cube software platform, X-Cube-AVS contains ready-to-use libraries and open routines that accelerate porting the AVS software development kit (SDK) to the microcontroller. Application samples are also included. The software abstracts developers from the complex software layers needed to host AVS on an embedded device. STMicroelectronics claims that this is the first package to cater specifically for microcontrollers. In contrast, AVS development usually targets more power-hungry and expensive microprocessors. As a result, X-Cube-AVS makes Alexa technology accessible to a wider spectrum of developers and projects, says STMicroelectronics.

The software handles low-layer communication and connection to AVS servers. It provides application-specific services, and encapsulates the AVS protocol to ease application implementation. Connection management includes a persistent-token mechanism for directly restoring connection losses without repeated user authentication. A software test harness is for endurance testing, which can simulate events such as network disconnection to facilitate robustness testing and validation of the user application.

X-Cube-AVS comes with a demonstration example for the STM32F769 Discovery kit which shows how to connect a simple smart-speaker to AVS, leveraging the board-configuration interface included in the software. X-Cube-AVS can be used with other STM32F7 microcontrollers, or any STM32 device with adequate CPU performance and memory to run the AVS SDK.

X-Cube-AVS is available now to download, free of charge, from the STMicroelectronics website.

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http://www.st.com

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