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Power Integrations' InnoSwitch cuts optocouplers from switching supply circuit Power Integrations has introduced several generations of off-line switching power supply ICs; the latest, Inno- Switch, returns to deriving feedback information to control output regulation direct from the output, but feeds that data back to the primary switch controller via an air-core magnetic coupler. Calling it FluxLink, PI says that its safety-isolated communication technology combines primary- and secondary-switcher circuitry to reduce component count, eliminate slow and unreliable optocouplers, outperform primary-side controllers and reduce manufacturing costs A single package with all necessary creepage and clearance spacings includes primary switching controller with integrated power FET on one die, secondary synchronous rectifier and associated circuitry on a second die, and the secondary-toprimary feedback path. This is implemented using the copper leadframe of the part. Part of the leadframe and chip bond wires form the 'primary' of a single-turn, air-core transformer (the 'primary' of the transformer is on the secondary or output side of the power supply layout, as it is passing output voltage level information back to the input switching controller). This loop couples to a further loop in the leadframe, connected to the controller IC; the physical layout is configured to cancel stray magnetic field effects. Clearances between the transformer loops are sufficient to give safety and regulatory isolation levels. On the PCB, the single package spans the gap between input and output sections. The InnoSwitch family of highly integrated switcher ICs, PI says, combines primary, secondary and feedback circuits into a single, worldwide safety-rated, surface-mount package that exceeds all global regulatory standards for efficiency and no-load consumption, while minimising component count and providing highly accurate constant voltage and constant current, up to 25W. The InnoSwitch family is suitable for smart mobile device chargers and adapters for a wide range of applications such as set-top boxes, networking equipment and computer peripherals. Unlike primary-side regulated switchers, InnoSwitch-based secondary-side regulated (SSR) designs are inherently less sensitive to the tolerance of external components such as transformers, diodes, resistors and capacitors. This increases manufacturing yield and reduces total power supply cost. Now, mobile device chargers up to 5A can have a total component count as low as PSR designs, with accurate CV and CC control (±3% and ±5% respectively) and Complete article, here low voltage ripple. pulse Raspberry Pi Model A+; latest design for embedding – in distribution With a smaller, lower-power board and HAT-compatible 40-pin GPIO as featured on Model B+, this board is more expandable, more embeddable and more mobile; RS Components now has the Raspberry Pi Model A+, which combines enhanced value and ease of use with smaller size and lower power consumption for applications such as industrial controls, remote monitors, and multimedia devices. The Raspberry Pi Model A+ has the 40-pin GPIO connector introduced on the Model B+, with the same pin-out and mounting holes for standard Hardware Attached on Top (HAT) accessories allowing users to add extra functions. The Model A+ utilises the Model B+ power architecture to achieve lower power consumption than the earlier Model A. With smaller board dimensions of 65 x 56mm, compared to 86 x 56 mm for the Model B+, the new Model A+ is more easily embeddable and better suited to mobile or battery-powered applications. Click here for the full version of this item. Prototyping accessories Also new on the Raspberry Pi scene, distributor element14 has launched the Microstack range, a series of accessories for the Raspberry Pi that will make it quicker and simpler for all levels of user to create and prototype physical devices; the first Microstack products are GPS positioning, accelerometer and prototyping modules. Microstack modules are positioned as the “building blocks for The Internet of Things for All”. Microstack was created by the designers of the original PiFace Digital and PiFace Control & Display accessories for the Raspberry Pi and the recent PiFace revisions for the Raspberry Pi model B+. Microstack builds on PiFace, offering many more connected-device possibilities. The Microstack GPS module provides easy plug and play solution for designs requiring GPS positioning to create geo-location aware projects. The module features standalone data logging and also brings globally synchronised, highly accurate time keeping to the Raspberry Pi. The Microstack Accelerometer module provides plug and play integration and development for designs requiring accelerometer such as robotics, tilt sensors, gaming, tracking and motion. It is based around a MMA8491Q, a low power, 3-axis low-g accelerometer offering multi-range 14-bit ± 8g resolution. The Microstack Protoboard module is a prototyping module allowing users to create their own circuit designs to be used with the Microstack form factor. Complete article, here www.edn-europe.com EDN Europe | DECEMBER 2014 7


EDNE DEC 2014
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