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), also known as pulse-duration modulation (PDM) or pulse-length modulation (PLM), is any method of representing a signal as a rectangular wave with a varying duty cycle (and for some methods also a varying peri ...

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 and published by the Institute of Electrical and Electronics Engineers. The first issue of ''IEEE Spectrum'' was published in January 1964 as a successor to ''Electrical Engineering''. In 2010, ''IEEE Spe ...

'' 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 are a ...

or fully analog techniques. Currently available implementations use a loop similar to a higher order

Delta-Sigma Delta-sigma (ΔΣ; or sigma-delta, ΣΔ) modulation is an oversampling method for encoding signals into low bit depth digital signals at a very high sample-frequency as part of the process of delta-sigma analog-to-digital converters (ADCs) ...

(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, w ...

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 company, fabless semiconductor supplier that specializes in analog, mixed-signal, and audio Digital signal processor, DSP integrated circuits (ICs). Since 1998, the company's headquarters have ...

Products and applications

Tripath used to sell the amplifiers as

chip Chip may refer to: Food * Chip (snack), thinly sliced and deep-fried gastro item ** Potato chips (US) or crisp (UK) * Chips (fried potato strips) (UK) or french fries (US) (common as a takeout side) * Game chips, thin chip/French fries * Choco ...

s, or as

chipset In a computer system, a chipset is a set of electronic components on one or more integrated circuits that manages the data flow between the processor, memory and peripherals. The chipset is usually found on the motherboard of computers. Chips ...

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

Sony is a Japanese multinational conglomerate (company), conglomerate headquartered at Sony City in Minato, Tokyo, Japan. The Sony Group encompasses various businesses, including Sony Corporation (electronics), Sony Semiconductor Solutions (i ...

Panasonic is a Japanese multinational electronics manufacturer, headquartered in Kadoma, Osaka, Kadoma, Japan. It was founded in 1918 as in Fukushima-ku, Osaka, Fukushima by Kōnosuke Matsushita. The company was incorporated in 1935 and renamed and c ...

and

Blaupunkt Blaupunkt GmbH () was a German manufacturer, producing mostly car-audio gear and other electronic equipment. Owned by Robert Bosch GmbH from 1933 until 1 March 2009, it was sold to Aurelius AG of Germany. It filed for bankruptcy in late 2015 ...

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 occupants. Such systems are popularly known as car stereos. Until the 1950s, it consisted of a simple AM radio. Additions sin ...

s and integrated

home cinema A home cinema, also called home theater, is a home entertainment audio-visual system that seeks to reproduce a movie theater experience and mood using consumer grade electronic video and audio equipment and is set up in a private home. In ...

systems *

Apple Computer Apple Inc. is an American multinational corporation and technology company headquartered in Cupertino, California, in Silicon Valley. It is best known for its consumer electronics, software, and services. Founded in 1976 as Apple Computer Co ...

used them in their

Power Mac G4 Cube The Power Mac G4 Cube is a Mac personal computer sold by Apple Computer, Inc. between July 2000 and 2001. The Cube was conceived as a miniaturized but powerful computer by Apple chief executive officer ( CEO) Steve Jobs and designed by Jony ...

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 by ...

(Digital audio),

eMac The eMac (short for education Mac) is a discontinued all-in-one Mac 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 chea ...

and iMac (Flat Panel) computers *

Audio Research Audio Research Corporation ("ARC") is one of the oldest manufacturers of high-end audio equipment still in operation. The company was known to be a pioneer at advancing state-of-the-art audio reproduction in the 1970s, and for re-introducing the ...

, an audio electronics company, formerly an exclusive tube circuit specialist, produced a Tripath-based audiophile amplifier. *

Virtue Audio Virtue Audio was a manufacturer of integrated amplifiers based on the Tripath microprocessor chip, also known as a, class-T, class D or switching amplifier. The company produces unusually small, brightly colored, value-priced amplifiers that produ ...

used them in their ONE, TWO, and Sensation range of amplifiers from around 2008–2014.

References

External links

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