AUSTIN, Texas – September 18, 2000 – Cirrus Logic Inc. (NASDAQ:CRUS), the world’s market leader in audio chips, today announced a significant advancement in Crystal® audio technology incorporating Pulse Width Modulation (PWM) that reduces power requirements for audio amplifiers, dramatically improves sound quality and reduces cost and complexity of design. Cirrus Logic’s “true digital” PWM technology also solves many of the problems associated with electromagnetic and radio frequency interference (EMI/RFI) usually encountered with existing Class D amplifiers and hybrid analog/digital PWM technologies.
The new digital PWM technology increases the efficiency of amplifiers from the industry norm of approximately 50 percent to near 90 percent. Existing systems that require 1,000 watts input to the amplifier to deliver 500 watts to the speakers, for example, can now deliver 900 watts from that same 1,000 watt input with Cirrus Logic’s digital PWM technology.
The fully digital PWM amplifiers also radiate significantly less EMI/RFI and because they are more power efficient, dissipate less heat (i.e., wasted energy). Taken together, these advances mean that designers can reduce the size of a typical power amplifier by a factor of four, allowing the amplifier to be built into a speaker or other small enclosure. Increased efficiency also facilitates battery-powered amplifiers that can run up to three times as long per charge compared to conventional amps.
“Audio hardware manufacturers are under constant pressure to reduce costs, improve sound quality, and decrease the size of their amplifier solutions,” said Mike Feibus, a principal analyst at Mercury Research, Inc. in Scottsdale, Ariz. “Using PWM-based class-D amplifiers can help these manufacturers achieve all three goals.”
“Cirrus Logic has addressed several key obstacles to delivering cost-effective, high-performance digital amplifier technology,” said Jason Carlson, vice president and general manager of Cirrus Logic’s Consumer Products Division. “We’ve combined superior intellectual property with our unparalleled engineering knowledge base and semiconductor manufacturing expertise to deliver true digital PWM technology. Using Cirrus Logic reference designs OEM products should deliver marked increases in dynamic range -- 120dB versus 90 to 95dB -- with tighter bass response and crisp, clean high-end sound.”
Cirrus Logic is offering OEMs a complete end-to-end solution for designing, building and manufacturing digital PWM amplifiers that can power audio devices ranging from less than one watt to hundreds of watts to high-end professional systems requiring thousands of watts of power. Total solutions embodied in a suite of reference designs offer OEMs quicker time-to-market for advanced audio products in professional, automotive and consumer markets. Cirrus Logic solutions include embedded digital signal processor (DSP) technology, audio firmware, amplifier control software, converters and interface technology. The embedded DSP and a high level of integration eliminate the need to carefully select matched components, removing a significant obstacle to producing a cost-effective, high-performance amplifier.
Cirrus Logic’s digital PWM technology outperforms existing analog and hybrid designs by delivering greater signal-to-noise (S/N) ratio, less total harmonic distortion (THD), wider dynamic range and better frequency response.
“We have assembled a team of dedicated audio IC, DSP and power engineers with a combined experience of more than 100 man-years, working together to develop the next generation in PWM amplifier technology,” says Dr. Skip Taylor, vice president of PWM technologies for Cirrus Logic. “We know where the inadequacies of the conventional approaches are and we have the expertise and the technology to fix them. We have not only broken down the barriers in performance that are inherent in today’s conventional PWM technology, we can surpass the performance of the best linear approaches as well.”
Markets for Digital PWM Technology
“Everywhere you find a speaker is a potential market for our digital PWM technology,” added Carlson. “We anticipate that the first applications for digital PWM will be in high-end, professional audio amplifiers and musical instruments. The technology will also find quick acceptance in consumer markets for automotive audio systems, portable audio devices, home hi-fi systems and personal computer audio.”
Professional audio applications could include integrated power amplifiers, headphone/line drivers, public address systems and powered monitor speakers.
Automotive applications include multi-channel processor/amplifiers and distributed amplifiers that could deliver increased power and sound-enhancement features for vehicle sound systems. Consumer electronics devices that could benefit from digital PWM technology include televisions, Internet Appliances, DVD players, home stereo systems, bookshelf and wireless speakers, intercom and paging systems, game consoles, portable music players and PC multimedia systems.
Digital PWM Amplifier Advantages and Performance
“Unlike analog and hybrid designs, our digital PWM technology will follow the digital semiconductor process technology roadmap of shrinking geometry and denser switches, which translates into greater system integration, higher performance and lower cost of manufacturing,” Carlson explained. “We offer a total solution that will be difficult for the competition to match -- embedded DSP technology, audio firmware and software, interface technology and power amplifiers to couple with analog and digital audio sources.”
At the heart of Cirrus Logic’s digital PWM technology is a DSP that controls the power amplifier circuitry and handles audio processing tasks. The embedded DSP also provides a “sync lock” for a switching power supply to eliminate the frequency fluctuations common to other amplifier designs. At the same time, the customer programmable DSP processes the audio signal, providing functions such as equalization, gain control, dynamic range processing and active crossovers for bi-amplification systems. The technology is adaptable and automated in that the DSP constantly monitors the amplifier environment and automatically adjusts parameters in real time to optimize for performance and efficiency.
The dramatic increase in power efficiency is due primarily to the ability to use switched power output devices rather than the conventional Class AB linear/analog approach. By using a completely digital PWM technology, rather than the hybrid analog/digital PWM technology, Cirrus Logic’s approach breaks the barriers that have limited the performance of these existing PWM systems. The embedded DSP controls the speed of switching and the associated “dead times” and effectively minimizes the generation of high frequency noise that has plagued PWM amplifiers in the past.
The DSP also constantly monitors the amplifier’s output load and senses both signal voltage and current simultaneously. This enables the amplifier to adjust to load changes in real time, providing a stable platform under widely varying load conditions typically encountered in “real world” speaker applications.
Cirrus Logic’s digital PWM amplifier reference designs address four different levels of the market, ranging from low-powered applications to high performance, high power applications. Reference designs cover a range of power and performance levels:
About Cirrus Logic
Cirrus Logic is a premier supplier of high-performance analog and DSP chip solutions for Internet entertainment electronics. Building on its global market share leadership in audio integrated circuits and its rich mixed-signal patent portfolio, the company targets high-volume audio, storage and communications applications. Cirrus Logic sells its products under the Crystal®, Maverick™ and 3Ci™ brands as well as its own name. Founded in 1984 in Silicon Valley, Cirrus Logic operates from headquarters in Austin, Texas and major sites located in Fremont, California and Broomfield, Colorado as well as offices in Europe, Japan and Asia. More information about Cirrus Logic is available at www.cirrus.com.
Safe Harbor Provision
Any forward looking statements and all other statements that may be made in this news release that are not historical facts are subject to a number of risks and uncertainties, and actual results may differ materially. Please refer to Cirrus Logic’s current Form 10-K and other filings with the Securities and Exchange Commission for more information on the risk factors that could cause actual results to differ.
Note to editors: Cirrus Logic, Crystal® and Maverick™ are registered trademarks of Cirrus Logic Inc. All other product names noted herein may be trademarks of their respective holders.
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