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Class D amplifiers present us with a revolutionary solution, which would help
us eliminate loss and distortions caused due to conversion of digital signals
to analog while amplifying signals before transmitting it to speakers. This inchoate
piece of knowledge could prove to detrimental in improving and redefining essence
of sound and take it to a different realm.
This type of amplifiers do
not require the use of D-A conversion and hence reduce the costs incurred for
developing state of art output technology. The digital output from sources such
as CD's, DVD's and computers now can directly be sent for amplification without
the need for any conversion. Another important
feature of these unique and novel kind of amplifiers are that they give us a typical
efficiency of 90% compared to that of the normal ones which give us a efficiency
of 65-70%. This obviously means less amount of dissipation that indirectly means
lower rated heat sinks and low waste of energy. This makes the use of D type amplifiers
in miniature and portable devices all the more apt. All
these years D type amplifiers have been used for purposes where efficiency was
the key whereas now developments in this technology have made its entry possible
into other domain that are less hi-fi. Thus showing up in MP3 players, portable
CD players, laptop computers, cell phones, even personal digital assistants. Digital
Audio's Final Frontier-Class D Amplifier Introduction
Digital technology continues its march from media like CDs and DVDs toward your
audio speakers. Today, amplifiers based on digital principles are already having
a profound effect on equipment efficiency and size. They are also beginning to
set the standard for sound quality.
An
old idea, the Class D amplifier has taken on new life as equipment manufacturers
and consumers redefine the musical experience to be as likely to occur in a car,
on a personal stereo, or on an airplane as in a living room. For most consumers
today, portability and style outweigh other factors in the choice of new audio
gear. Class D amplifiers are ideally suited to capitalize on the trend. They are
already starting to displace conventional high-fidelity amplifiers, particularly
in mobile and portable applications, where their high efficiency and small size
put them in a class by themselves. For example, they are fast becoming the dominant
technology for entertainment systems in cars, where passengers are now apt to
watch a DVD-and expect from the vehicle's compact, ill-ventilated electronics
the same rousing surround-sound experience they get at home.
The
new amplifiers can provide it. They are typically around 90 percent efficient
at rated power, versus 65-70 percent for conventional audio amps. Such high efficiency
means, for one thing, that the amplifiers can get by with much smaller heat sinks
to carry away the energy they waste. Also, portable devices like MP3 players can
go much longer on a battery charge or can be powered by tinier, lighter batteries.
Class D amplifiers have been used for decades
in industrial and medical applications when high efficiency is key. They have
been applied with great success in devices as small as hearing aids and as large
as controllers for hefty motors and electromagnets. They blossomed as a significant
force in high-fidelity audio a few years ago, when Class D power amplifier chips
were released by companies like Tripath Technology, Texas Instruments, and Cirrus
Logic in the United States; Philips and STMicroelectronics(partnering with ApogeeDDX)
in Europe; and Sanyo (partnering with Bang & Olufsen) in Japan.
More
recently, Class D amps have expanded beyond the hi-fi niche, showing up in MP3
players, portable CD players, laptop computers, cellphones, even personal digital
assistants (PDAs). At the same time, they have been making forays into the world
of home audio in the form of products based on those new chips. Notable entries
include amplifiers from Bel Canto Design Ltd. (Minneapolis, Minn.) and PS Audio
(Boulder, Colo.).
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