Class T was a registered trademark for a switching (class-D) audio amplifier, used for Tripath's amplifier technologies (patent filed on Jun 20, 1996). Similar designs have now been widely adopted by different manufacturers.

Amplifier

The covered products use a class-D amplifier combined with proprietary techniques to control the

pulse-width modulation Pulse-width modulation (PWM), or pulse-duration modulation (PDM), is a method of reducing the average power delivered by an electrical signal, by effectively chopping it up into discrete parts. The average value of voltage (and current) fed ...

to produce what is claimed to be better performance than other class-D amplifier designs. Among the publicly disclosed differences is real time control of the switching frequency depending on the input signal and amplified output. One of the amplifiers, the TA2020, was named one of the twenty-five chips that 'shook the world" by the ''

IEEE Spectrum ''IEEE Spectrum'' is a magazine edited by the Institute of Electrical and Electronics Engineers The Institute of Electrical and Electronics Engineers (IEEE) is a 501(c)(3) professional association for electronic engineering and electrical e ...

'' magazine. The control signals in Class T amplifiers may be computed using

digital signal processing Digital signal processing (DSP) is the use of digital processing, such as by computers or more specialized digital signal processors, to perform a wide variety of signal processing operations. The digital signals processed in this manner ar ...

or fully analog techniques. Currently available implementations use a loop similar to a higher order Delta-Sigma (ΔΣ) (or sigma-delta) modulator, with an internal digital clock to control the sample comparator. The two key aspects of this topology are that (1), feedback is taken directly from the switching node rather than the filtered output, and (2), the higher order loop provides much higher loop gain at high audio frequencies than would be possible in a conventional single pole amplifier. Blaupunkt PA2150 T-Amp top

Financial difficulties caused Tripath to file for

Chapter 11 Chapter 11 of the United States Bankruptcy Code ( Title 11 of the United States Code) permits reorganization under the bankruptcy laws of the United States. Such reorganization, known as Chapter 11 bankruptcy, is available to every business, whet ...

bankruptcy protection on 8 February 2007. Tripath's stock and intellectual property were purchased later that year by

Cirrus Logic Cirrus Logic Inc. is an American fabless semiconductor supplier that specializes in analog, mixed-signal, and audio DSP integrated circuits (ICs). Since 1998, the company's headquarters have been in Austin, Texas. The company's audio proces ...

Products and applications

Tripath used to sell the amplifiers as

chip Chromatin immunoprecipitation (ChIP) is a type of immunoprecipitation experimental technique used to investigate the interaction between proteins and DNA in the cell. It aims to determine whether specific proteins are associated with specific genom ...

s, or as

chipset In a computer system, a chipset is a set of electronic components in one or more integrated circuits known as a "Data Flow Management System" that manages the data flow between the processor, memory and peripherals. It is usually found on t ...

s, to be integrated into products by other companies in several countries. For example: *

Sony , commonly stylized as SONY, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan. As a major technology company, it operates as one of the world's largest manufacturers of consumer and professional ...

Panasonic formerly between 1935 and 2008 and the first incarnation of between 2008 and 2022, is a major Japanese multinational conglomerate corporation, headquartered in Kadoma, Osaka. It was founded by Kōnosuke Matsushita in 1918 as a lightbulb ...

and

Blaupunkt Blaupunkt GmbH () was a German manufacturer of mostly car audio equipment. It was owned by Robert Bosch GmbH from 1933 until 1 March 2009, when it was sold to Aurelius AG of Germany. It filed for bankruptcy in late 2015 with liquidation procee ...

use them in several

car stereo Vehicle audio is equipment installed in a car or other vehicle to provide in-car entertainment and information for the vehicle occupants. Until the 1950s it consisted of a simple AM radio. Additions since then have included FM radio (1952), ...

s and integrated

home cinema Home cinema, also called home theaters or theater rooms, are home entertainment audio-visual systems that seek to reproduce a movie theater experience and mood using consumer electronics-grade video and audio equipment that is set up in a roo ...

systems *

Apple Computer Apple Inc. is an American multinational technology company headquartered in Cupertino, California, United States. Apple is the largest technology company by revenue (totaling in 2021) and, as of June 2022, is the world's biggest company ...

used them in their

Power Mac G4 Cube The Power Mac G4 Cube is a Macintosh personal computer sold by Apple Computer, Inc. between July 2000 and 2001. Designed by Jonathan Ive, the Cube was conceived by Apple chief executive officer (CEO) Steve Jobs, who held an interest in a powerf ...

Power Mac G4 The Power Mac G4 is a series of personal computers designed, manufactured, and sold by Apple Computer from 1999 to 2004 as part of the Power Macintosh line. Built around the PowerPC G4 series of microprocessors, the Power Mac G4 was marketed b ...

(Digital audio),

eMac The eMac (short for education Mac) is a discontinued all-in-one Macintosh desktop computer that was produced and designed by Apple Computer Released in 2002, it was originally aimed at the education market, but was later made available as a ...

and iMac (Flat Panel) computers *

Audio Research Audio Research Corporation is one of the oldest manufacturers of high-end audio equipment still in operation. They were pioneers at advancing the state-of-the-art for audio reproduction in the 1970s, re-introducing the vacuum tube as the primar ...

, an audio electronics company, formerly an exclusive tube circuit specialist, produced a Tripath-based audiophile amplifier. * Sonneteer, a British hifi company, analogue amplifier and technology specialists, manufactured the Bronte amplifier (1999), based around a Tripath class-T module. *

Bel Canto Design BEL can be an abbreviation for: * The ISO 3166-1 alpha-3 country code for Belgium * ''BEL'' or bell character in the C0 control code set * Belarusian language, in the ISO 639-2 and SIL country code lists * Bharat Electronics Limited, an Indian ...

used them in their eVo range of amplifiers. * Virtue Audio used them in their ONE, TWO, and Sensation range of amplifiers from around 2008–2014. * Sonneteer, a British hifi company, analogue amplifier and technology specialists, manufactured under Sub Brand Bard Audio, the BardThree amplifier (2005), based around a Tripath class-T chip and is/was known as the Plug Top or Rug Rat amp.

References

External links

US Patent for Class T amplifier
{{DEFAULTSORT:Class T Amplifier T Switching amplifiers Electronic amplifiers