EDNE June 2012 - (Page 9)

eDn.comment By graham prophet, eDitor ,, High-Voltage Buck Control ICs Constant LED Current Regulation he history of electronics has been charted by technologies that have been pushed, repeatedly, far beyond what appeared possible in their early stages. Elsewhere in this issue you will find mention of digital oscilloscopes from the leading providers in that market that now offer analogue bandwidths upwards of 60 GHz. Such is the rate of progress that if I write such a figure in a headline in a certain edition of the magazine, it is astonishing: a few months pass, it becomes accepted, and we wait for the instrumentation companies to extend the limits once again. The landscape of test instrumentation changes constantly; previously, for any given generation, you understood that up to a certain frequency, you might be able to use a real-time instrument. Beyond that figure, you would need to use sampling scopes or shift to the frequency domain to infer what your signal was really doing. Our capacity to be astonished by performance gains is quickly attenuated. This is something we should resist: the idea that we can look in real-time at a signal in the high-microwave region is a spectacular achievement in measurement technology, and we should make an effort to (inwardly, at least) say, “65 GHz. Wow”, for longer than a few months after the headline appears. In May, the annual PCIM conference and exhibition provided examples of a similar theme, but at the component level. Established silicon power switch technology (MOSFETs and IGBTs, for the most part) faces a potential challenge from gallium nitride and silicon carbide devices – as and when the aspiring device makers can deliver. Silicon carbide is well established for high-power, hightemperature diodes; both materials will potentially make efficient power switches with appealing characteristics, but users have become used to waiting for that day to dawn. Over many years, vendors exhibiting at events such as PCIM would say, “A competitive switch in SiC/ GaN will be here soon… by next year… or maybe a little longer.” Then, in 2011, there were signs that a turning point had been reached; multiple vendors were able to show prototypes and say, “Look; a high-mobility-material switch”. You could not buy them, certainly not in quantity, but the fundamental device designs were out there. And so to 2012 and what do we find? The relative maturity of SiC technology has been revealed as you can now source SiC switches from multiple vendors. Or, to www.edn-europe.com T Life in the fast lane LEDrivIR™ IRS2980 Features IRS2980 Benefits be more accurate, favoured lead customers can obtain such parts – their progress towards being commodities is halting. And a few – perhaps, a very few – GaN parts are in the marketplace. But in classic electronics-industry fashion, what has been happening all the while? Makers of conventional silicon devices have been pushing the boundaries, and not necessarily by small increments. The parametric “space” in which you might have concluded you would need a new technology to create a viable design turns out to be accessible to established technologies, after all. I’ll cite just one parameter, from one vendor; Toshiba introduces a 600-V FET with an on-resistance of 0.04Ω. In an attempt to maintain the “wow” factor, I suggest reading that again; 40 milliOhms, in a 600-V part. How good does your interconnection, and product assembly, have to be not to dwarf such figures with losses elsewhere in a design? Of course, there will be many alternate reasons that engineers will look to the new technologies, but it’s a reminder that those proposing disruptive innovations – like GaN and SiC – are never, in this industry, aiming at a fixed target. Part Number Package Voltage Gate Drive Current Startup Current Frequency IRS2980S SO-8 450V +180 / -260mA 250 µA <150 kHz IRS25401S IRS25411S SO-8 200V +500 / -700mA 50 µA <500 kHz SO-8 600V +500 / -700mA 50 µA <500 kHz For more information call +49 (0) 6102 884 311 or visit us at www.irf.com JUNE 2012 | EDN EuropE 9 THE POWER MANAGEMENT LEADER http://www.irf.com http://www.edn-europe.com

Table of Contents for the Digital Edition of EDNE June 2012

Agilent Technologies
International Rectifier
RS Components
International Rectifier
Analog Devices
Test & Measurement
Silicon Labs
Test-driven development for embedded C: why debug?
Baker’s best
Cover story
Rohde & Schwarz
Rohde & Schwarz
Rohde & Schwarz
Rohde & Schwarz
Rohde & Schwarz
Pico-projector design uses color LEDs
Digital isolation in smart energy metering applications
Mechatronics in design
Design Idea
Product Roundup
Tales from the cube

EDNE June 2012