[Technology Report] FPGAs Add A Flexible Dimension To Digital Design
Logic design at the gate or module level for discrete implementations has effectively gone away, with the exception of buffers and analog designs. The move to micros has turned much of today’s system design into large chips and software. Custom logic is still needed, but it often resides in ASICs, complex programmable logic devices (CPLDs), and FPGAs. ASICs aren’t a bad choice if you have gobs of money and time, along with an engineering team. ...
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William Wong
[Technology Report] Tools Make Motion-Control Design A Snap
One of the most challenging and widespanning areas of design work involves motors and motion control. Choosing the right motor and related control circuitry is one thing. Getting it all to fit into the end product and work accurately is another. And, as with any mechanical component, the opportunities for error are many. Fortunately, motor makers offer users many powerful tools to take the vinegar out of their design chores. More often than not, these...
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Mat Dirjish
[Design View / Design Solution] Filter Trims Ultra-Precision Voltage Reference
VOLTAGE REFERENCES GENERATE WIDEBAND noise spectrums. For most semiconductor devices, this spectrum usually has a wideband “white noise” component with relatively constant power density versus frequency, and a “pink noise” or “1/f noise” component that grows with the inverse of frequency.1,2 The pink noise component rises up from the relatively flat white noise level at a point somewhere between a few hundred hertz and a kilohertz, and it increases 3 dB ...
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Alfredo Saab
, et al.
[Ideas For Design] A Look Back At 40 Years Of Ideas For Design
After Electronic Design asked me to contribute something to this special issue, all kinds of possibilities ran through my mind. After all, it had been 40 years since my first ED article, which was itself an Idea for Design (IFD), “Gated Amplifier Uses FET in Feedback Loop,” in the Jan. 4, 1968 issue. So, what’s an IFD? The snappy answer is that it’s one of Electronic Design’s most popular editorial features. But more germane...
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Walt Jung
[Ideas For Design] The IFD Culture—An Interview With Hall Of Famer Bob Dobkin
Linear Technology’s Chief Technology Officer Robert Dobkin has been contributing Ideas for Design (IFDs) since his youth. He’s still enthusiastic about them. “I remember one I wrote when I was a kid. It was a current source that you could pulse on or off. I don’t know how many letters I got from that,” he said. “It had just two or three transistors in it, but it was really effective in terms of people coming back to me after reading it, which...
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Don Tuite
[Ideas For Design] Use IFDs To Develop And Showcase Your Design Concepts
Electronic Design published my first Idea for Design, “AC-DC Converter Runs Off One Power Supply” (April 16, 1992, p. 93), more than 16 years ago (Fig. 1). It set a theme that I have continued to employ ever since—using the nifty venue of IFDs to present and develop new circuit design ideas and themes to the engineering community. Over the years, examples of some of those basic concepts and ...
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W. Stephen Woodward
[Ideas For Design] Then, Now, And Beyond—System Design In The 21st Century
I remember the day it arrived. All of our design engineers gathered around the lab bench waiting for our technician to unpack the box. As it was slowly lifted from the protective cardboard packing and set on the bench, we all looked on in amazement— 5 Mbytes in a single hard drive that could fit in your hand! It was a Control Data Corporation ST-506-compatible hard-disk drive that weighed 4.5 lb and consumed around 40 W. Just about everyone made some...
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Richard F. Zarr
[Ideas For Design] A Look Back At 40 Years Of Ideas For Design
After Electronic Design asked me to contribute something to this special issue, all kinds of possibilities ran through my mind. After all, it had been 40 years since my first ED article, which was itself an Idea for Design (IFD), “Gated Amplifier Uses FET in Feedback Loop,” in the Jan. 4, 1968 issue. So, what’s an IFD? The snappy answer is that it’s one of Electronic Design’s most popular editorial features. But more germane is...
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Walt Jung
[Ideas For Design] Single Op-Amp Peak Detector Features Signal Accumulation: Backstory
FIGURE 1 DEMONSTRATES A one-way switchedcapacitor gain stage circuit, performing a voltage gain of AO = C1/C2 only during the decreasing trail of the input signal VI (with VJ = 0). During the positive signal variations, the output doesn’t change, thereby implementing an incremental peak-detector and accumulator circuit. This device can be used to measure the...
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Massimo Gottardi
[Ideas For Design] Bidirectional H-Bridge DC-Motor Motion Controller: Backstory
IN APPLICATIONS REQUIRING ABSOLUTE accuracy in the speed control of dc servo motors, there’s no substitute for the traditional tachometerbased feedback loop. But for somewhat less demanding situations, adequate accuracy often can be achieved without the complication and expense of a tach. This can be done by taking advantage of the built-in electromechanical constants of the motor itself. For example,...
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John Peterson
, et al.
[Ideas For Design] Use Excel To Develop A Traceability Matrix: Backstory
A subrequirement that derives from multiple primary requirements can be achieved using the concatenation of the cells in the reference coupled with a line-feed character. For example, if CEI requirements 1.3.3 and 1.3.4 drive requirement 2.1.9 of the lower document, cell D11 would contain the Excel formula =A4 & CHAR(10 )& A5. To achieve the multiple line effect, the cell should be formatted to allow Wrap Text (in the Alignment...
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Aubrey Kagan
[Ideas For Design] Reference Designs Play A Dual Role
At one time, reference designs were simply helpful guides to the finer details of designing a part into a board. Those days are long gone. The complexity of today’s devices, in addition to the fast pace of many markets, has forced some reference designs to evolve beyond educational tools into manufacturing documentation for fully defined end products (Fig. 1). This dual role leaves...
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Richard Quinnell
[Ideas For Design] For Checking Software Without Hardware, FPGAs Are The Answer
An age-old truism in the system design realm is that the software is always ready to be checked out before first ASIC silicon is in hand. This leaves the members of the design team with an equally ageold conundrum: How are they to verify their first crack at an application stack and associated drivers without hardware to run them on? Waiting until that first silicon comes from the fab is an uncomfortable and often untenable option. The answer,...
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David Maliniak
[Ideas For Design] Triple-Output LED Driver Works With Common-Anode LED Strings
SOME MULTI-STRING LED MODULES come with a common-anode configuration. The commonanode connection reduces the number of wires between the LED module and its driver from 2N to N+1, where N is the number of LED strings in the module. In this idea, we’ll drive a commonanode LED module while simultaneously limiting the LED string voltage when an LED string becomes open. Figure 1 shows the LT3496...
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Hua (Walker) Bai
[Ideas For Design] "Ultimate" Continuity Tester Hides Many Tricks Up Its Sleeve
I WAS REMINDED RECENTLY of a tester I designed years ago. At the time, I wanted to build “The Ultimate Continuity Tester,” and I established a wish list of all the features I required: • A “real continuity” tester. Too many multimeters and sounders react at resistances as high as hundreds or even thousands of ohms, which makes them practically useless in many cases. Within a board or a system, there are always medium-conductivity...
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Louis Vlemincq
[Ideas For Design] Inexpensive High-Speed Amplifiers Can Create Flexible Clock Buffers
IN CONSUMER ELECTRONICS APPLICATIONS, which tend to be lower in frequency and less demanding than typical clock-buffering applications, inexpensive high-speed op amps (~100-MHz bandwidth) can offer an attractive option in place of traditional clock buffers. High-speed amplifiers can be less expensive than traditional clock buffers, yet they’re able to accommodate a wide range of design configurations. For instance, one good alternative for...
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John Ardizzoni
[Ideas For Design] Add Coordinated Overcurrent, Overvoltage Protection To PoE Equipment
POWER OVER ETHERNET (POE) enabled devices and their electronic components are designed for operation within specified current and voltage ratings. If these ratings are exceeded due to short-circuit or voltage transients, components may sustain permanent damage and the equipment may fail. Overcurrent and overvoltage protection devices are used to help protect both power-sourcing equipment (PSE) and powereddevice (PD) equipment. A growing...
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Matt Williams
[Ideas For Design] Perform Coarse And Fine Correction With Less Costly Dual DCPS
DIGITALLY CONTROLLED POTENTIOMETERS (DCPS) find uses in a wide variety of systems for setting bias currents, variable reference voltages, and calibration settings. In industrial control and automation applications, high accuracy is a must. DCPs with 1024 taps are available, but for a few dollars instead of tens of cents. A dual, 32-tap, 50-k DCP is available for 40 cents. Can we use both of the DCPs in the package and reach similar performance to the 1024...
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Reza Bahadur
, et al.
[Ideas For Design] "Take-Back-Half" Convergence Algorithm Stabilizes Microhydro Turbine Controller
THE SOARING COSTS OF fossil fuels, combined with environmental concerns like climate change, are driving the increased interest in renewable (“green”) energy. No energy source is “greener” than hydroelectric power, particularly small (“microhydro”) installations that involve minimal artificial water impoundment and associated environmental impact. Even with an adequate water source, however, efficient and cost-effective implementation of appropriate...
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W. Stephen Woodward
[Ideas For Design] Who Actually Designs Reference Designs?
It’s fair to say there are really two kinds of reference designs. One is developed by chip companies that want a permanent foothold in an original device manufacturer’s high-volume platform in a consumer market. The other is produced by a chip company’s Web-based or downloadable PC tool that lets ordinary bench engineers mix and match ICs, simulate circuits, and obtain bills-of-materials (BOMs) and sometimes actual circuit board reference designs. ...
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Don Tuite
[Ideas For Design] Easily Convert Decimal Numbers To Their Binary And BCD Formats: Backstory
HERE’S A C/C++ PROGRAM that converts decimal numbers ranging from 0 to 99,999 to binary and binary coded decimal (BCD) formats. Using a simple algorithm in conjunction with pointer arithmetic and bitwise shifting increases the conversion speed without introducing excessive memory overhead and programming complexity. When decimal numbers are within the range of 0 to 9, their binary and BCD representations are identical, requiring only four bits...
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Edmond Vinarub
[Ideas For Design] Take Your Next Design From Statecharts To Code
SOME BACKGROUND Also known as state diagrams, statecharts can be found on napkins and coding screens as designers turn ideas into application code. They’re simple to use and understand, as they’re just a bunch of “circles and arrows and a paragraph on the back of each one explainin’ what each one was, to be used as evidence against us,” to quote Arlo Guthrie and his classic song, “Alice’s Restaurant.” Events cause transitions...
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William Wong
[Editorial] After All These Years, Ideas For Design Get The Royal Treatment
One of the most popular sections of Electronic Design in both print and on the Web over the years has been Ideas for Design (IFDs). We’d like to celebrate this department by dedicating this entire issue to IFDs, including insightful commentary from our editors and contributors alike. First, we’ve asked some of the industry’s top engineers, who we like to call design gurus, to reflect and write about the circuits they’ve created over the ...
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Joseph Desposito
[Pease Porridge] What's All This Analog Engineering Stuff, Anyhow?
For many years, aficionados of digital circuits and computers have bragged that their rapid advances will leave all analog circuits lying in the dust. The analog business is shrinking, at least compared to the success of digital computers. Moore’s law has made sure of that for many years. The tiny transistors are smaller and faster than ever, even if they can’t stand off 5 V (Fig. 1). ...
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Bob Pease
