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Real World Interface

Wolfson Microelectronics has been one of Scotland's highest achievers in the electronics industry for more than 20 years. Thanks to its expertise in mixed-signal technologies, it “accidentally” got into the consumer space eight years ago, providing solutions for top-selling products like the iPod and Xbox, but its spectacular success since then has not been any accident...…

Real World Interface

Wolfson Microelectronics has been one of Scotland's highest achievers in the electronics industry for more than 20 years.

Thanks to its expertise in mixed-signal technologies, it "accidentally" got into the consumer space eight years ago, providing solutions for top-selling products like the iPod and Xbox, but its spectacular success since then has not been any accident...

According to Peter Frith, Wolfson Microelectronics has been

"punching above its weight" since it was founded, but today it is fighting in the same ring as some of the industry’s giants.

Frith, who is now the Chief Technical Officer, joined Wolfson back in 1985, when it employed just 16 people. But today the Edinburgh-based company employs about 375 people worldwide and has offices in 12 countries, including the US, Japan, China, Taiwan, Korea, Singapore and India, generating revenues of about £117 million last year – 10 times more than 2001. A major factor in this recent growth is Wolfson’s major breakthroughs in consumer electronics, working with large corporations like Microsoft, Apple and Sony to deliver high-performance audio and imaging solutions, with an emphasis on ultra-low power consumption. Its mixed-signal semiconductors can now be found in a wide range of devices such as mobile phones, digital cameras, flat panel TVs, portable navigation systems, Hi-Fis, all-in-one printers and scanners, as well as portable media players and gaming consoles.

Wolfson’s surge in business would have been very hard to predict just a few years ago. At the turn of the millennium, the high-tech industry was going through difficult times, but the portable communications market bucked all the trends, and when Apple started designing the iPod and Microsoft was busy with the Xbox, Wolfson was well placed to take full advantage...

How it happened

Right from the start, Wolfson had specialised in mixed signal technologies, avoiding the hot competition in the digital sector – like several other canny companies in Scotland at the time. This meant Wolfson focused on the interface between the real (analogue) world and the digital world, and spent its first 10 years designing custom mixed-signal solutions, in the process building up its expertise in audio, and mixed-signal circuits with low power consumption. Over time the company started building audio solutions for digital communication devices, including PDAs, and these became increasingly sophisticated (and much more compact) and evolved into solutions

Frith suggests that portable devices typically comprise five separate functional blocks – one each for display, processor, memory, RF (radio frequency) and ‘real-world’ interfaces (audio, power supplies, battery charging and sensors). It is this last category of ‘real-world’ interfaces that Wolfson targets with its technologies. The company is 100 per cent fabless, subcontracting manufacture of its semiconductors, so it can concentrate on its "tightly defined core competencies of product definition and design, and its in-house test and measurement facilities."

According to Frith, the challenge today is much the same as years ago – aiming for the smallest geometry and lowest power consumption per function, while building in the smartest, best-performance components - in other words, reducing cost and size at the same time as improving performance, packing in more features and extending the battery life.

Driving trends

In a global market changing every day, Wolfson also tries to keep one step ahead of the industry, driving trends and "defining better solutions" rather than simply following instructions.

For example, says Frith, when a customer has a new product designed to do one task, the Wolfson engineers may see the potential to incorporate other functions – like power management or fitting in an additional speaker driver.

"We always aim to establish a tight engineering relationship with all our customers," says Frith, "and try to find a better way of doing things, not just produce what they initially ask for."

One of Wolfson’s biggest initiatives in recent years has been a product strategy called AudioPlus(tm), broadening the scope of its audio products to focus on what the company describes as "Pure Sound, Smart Power, Enhanced Soundware and True Mics," including high-performance – or "mics on a chip." One of the latest additions to the AudioPlus(tm) product strategy is the WM8350 sound and power management solution

With pure sound, the aim is to reproduce audio signals as close to the real thing as possible, eliminating noise and distortion. "Power is a never-ending battle," says Frith. "As soon as the battery life is extended from two hours to eight hours, the product designers immediately add extra features which reduce it back down to two hours." Ultra-low-power-consumption CODECs, integrated power management functions and low-power amplifiers are among the ways that Wolfson addresses the problem.

Wolfson's Enhanced Soundware is built on technology it acquired with the purchase of a company called Sonaptic who developed audio software algorithms. Now Wolfson is combining these algorithms with its mixed-signal technologies to bring exciting new technology such as ambient noise cancellation to mobile handsets.

"First, we established credibility in the audio market," says Frith, "then we defined the devices. Now we have moved on to optimise the feature set, aiming for more inputs and outputs, lower power consumption and smaller size."

For Wolfson, it will always be important to predict where the industry’s going, says Frith. This means anticipating and helping to steer new developments in real world interface technologies like sensors, drivers and power supplies, including technologies such as MEMS (microelectromechanical systems or very small micromachines) for microphones, and future applications like accelerometers or ultrasonic sensors.

Some of these ideas seem out of this world to begin with, but now that the company is mixing it with some of the industry’s giants and shipping over 300 million silicon chips a year, it is more confident of betting on its future – in the real world.

Sound idea

The WM8350 is an integrated sound and power management solution developed by Wolfson, designed for use in portable media players, navigation devices and VoIP handsets – plus other portable devices powered by single-cell lithium batteries. The new device offers a high-performance audio CODEC for high-quality stereo playback and recording, and is compatible with leading multimedia application processors. It also incorporates low-power audio technology to extend the battery life, plus programmable on-chip amplifiers to enable direct connection of headphones and microphones.

According to Wolfson, the reduced external component count saves about 25 per cent on bill of materials (BOM) costs, while the compact size (7mmx7mm) saves up to 50 per cent on the physical PCB board area. Another benefit is built in "pops and clicks" suppression, which enhances the sound quality and reduces the need for external circuitry.

The WM8350 incorporates six DC-DC converters and four low-dropout regulators to generate programmable supply voltages for different components such as a digital core, I/O and backlight display, in addition to the integrated audio CODEC. This eliminates the need for separate power management ICs and reduces the overall component count.

An on-chip battery charger supports programmable charging modes for single-cell lithium batteries. The charge current, termination voltage and charger time-out are programmable to suit different Li-Ion or Li-Pol batteries. Automatic power supply selection between battery, USB or a wall adaptor enables ‘instant on’ operation even if the battery is fully discharged. Autonomous battery charging is possible whenever the USB or wall-adaptor supply is connected.

Internal power management functions control the start-up and shut-down sequencing of clocks and supply voltages. This provides protection in the event of undervoltage or extreme temperature conditions. It can also detect deeply discharged or defective batteries and adjust the charger parameters accordingly with a minimum of software involvement.


"Real World Interface". Science Scotland (Issue Seven)
Printed from on 05/07/20 11:19:54 PM

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