Talk:Switching amplifier

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Show the original waveform and then a PWM waveform and then a filtered output waveform. — Omegatron 04:17, 7 February 2007 (UTC)

Contents 1 PWM amplifier is subclass of Class D Amplifier 2 Misc 3 Merge Class T 4 Disadvantages of Class D amplifiers 5 Some absolute crap in the abstract (introduction) 6 Make "Switching Amplifier" an overview and reference separate articles about classes

[edit] PWM amplifier is subclass of Class D Amplifier

i suggest renaming the article class D amplifier. the PWM method is only ONE of the possible methods to modulate the active device on/off. today there are more advanced methods which cannot be categorized as PWM, such as the sigma-delta modulator of the class-D amplifier chip mentioned in the article (Analog Devices AD1990 Class-D audio power amplifier).

i would also suggest defining new articles for class E/F (today it's the same class, in the past it was 2 classes until it was realized they are basically two variants of one common methodology).

I would suggest that instead of renaming it to "Class-D amplifier", it would be better to call it "Switching amplifier". P.S.: Please sign with ~~~~ Rohitbd 08:53, 10 May 2006 (UTC)

But there are other types of switching amplifiers that are not PWM, no? — Omegatron 05:09, 12 May 2006 (UTC)

I can't think about any high frequency switching method that is not PWM: delta and sigma delta are different way to find out the value of the duty cycle, but we still end up with varying the duty cycle of a square wave to obtain a given average value. I think this is the definition of the PWM (and I edited the PWM article in that sense). So I think all switching amplifiers are PWM, though the PWM is computed using different methods. -- CyrilB 08:18, 12 May 2006 (UTC)

Yeah, I guess you're right. Even if there are other types, they probably don't deserve their own article. A single switching amplifier article should be good. I support the name change.

Make sure to be clear that the article is about amplifiers that switch the output stage to produce a waveform, and not analog amplifiers with switching power supplies. — Omegatron 13:25, 12 May 2006 (UTC)

Switching amplifier redirects to PWM amplifier...? So what's the final verdict? Rename to Switching amplifier or Class-D amplifier? Rohitbd 15:23, 13 May 2006 (UTC)

I like switching amplifier — Omegatron 04:40, 14 May 2006 (UTC)

Moved PWM amplifier to Switching amplifier. Rohitbd 07:58, 14 May 2006 (UTC)

I wrote the original comment at the top. agreed, switching amplifier is a good term. so, who wants to start a class E/F article (using the text located at electronic amplifier - class E/F as seed?

The ΣΔ produces a special kind of pulse trains, named Pulse Density Modulation (PDM). The variablity of pulse width in this scheme is limited to two discrete values {0, T}. That is, the switch remains open or closed along the whole cycle length. But who assures the PDM frequency invariability, which is prerequisite for PWM? Anyway, there are bunch of modulation schemes not belonging to the PWM class and even some closed-loop scemes, which, like linears, do not exploit any modulation at all. The control circuit must be distinguished from the whole amplifier, which is an aggregate device. The PWM is only one of the control circuit architectures possible and is related to the switching amplifiers as the notion of Monarchy to the notion of State or the Orange relates to Juice. The fact that you cannot think of apple juice is a bad argument. This also means that the PWM, which is a control method, is not a subclass of any amplifier, which is a device class. The amplifier topic might have a control scheme topic reffering to popular modulation and closed-loop designs. --Javalenok 18:45, 8 July 2006 (UTC)

[edit] Misc

Suggest that this article be merged with Electronic amplifier#Class_D. Wasn't aware that this has been covered elsewhere at the time of creation. Rohitbd 12:56, 5 August 2005 (UTC)

See Talk:Electronic_amplifier - Rohitbd 09:10, August 8, 2005 (UTC)

Another application worth mentioning for the Class D amplifier, especially in context to handling digital signals, are home-theatre receivers or home theatre in box systems that are based on this technology. Typically, they would use analogue-digital circuitry (for analogue inputs including the AM/FM tuner), accept digital inputs directly and do the processing or decoding in the digital domain before putting the signal out to Class-D power-amplifier circuits (typically 5 or 6 in the units that are affordable for most people). This is usually to permit the design of compact affordable equipment. SimonMackay (talk) 14:14, 11 February 2008 (UTC)

[edit] Merge Class T

Class T amplifier should be merged here, and this is the appropriate article for other vendor-specific "classes", such as Class I, and whatever else people come up with. — Omegatron 18:53, 8 August 2006 (UTC)

Agreed. Class T are also switching amps. Rohitbd 15:07, 12 August 2006 (UTC)

Oppose. It has its own page because it's a notable product in its own right. (I created the original article, if that matters) --Dtcdthingy 02:22, 16 August 2006 (UTC)

'Class T' is a proprietary implementation of a class D amplifier it is not a class it its own right. Perhaps there should be a section separate of the real classes of other or proprietary amplifiers which includes all other classes such as Class I (BCA) Class TD and Class T

Oppose the merge w/ Class T amplifier. This term is a commercial one (nd would on that ground not justify a separare WP atricle) for some amplifiers which are distinct in some ways from other switchers. Among other things, they have found acceptance across the entire range of audio amplifier use, from Audio Research to very small and inexpensive battery powered amps from Sonic Impact. This is unique in the amplifier world, hence a separate article is justified after all. .

On another point, the title of this article should not be Transistor amplifier, as there are many types other than switching amplifiers. And there several flavors of those. The curretn title has to go... ww 06:24, 20 March 2007 (UTC)

Is it a switching amplifier? — Omegatron 05:15, 26 July 2007 (UTC)

I oppose the merge with "Class T Amplifier" too. There are other commercial variants of the Class D too, and if we add them all as sections it would really clutter a Class D article. Esobocinski (talk) 19:57, 27 March 2008 (UTC)

I'd also oppose a complete merger. There's a level of detail that you would go to in the Class T article that doesn't belong in this type of overview article. It seems that the issue has been on the table for discussion for a long time, and that merger isn't appropriate, so it seems time to set that idea aside. Class D should be a subcategory of electronic amplifiers, and this article should be an overview that doesn't delve into the details of the may implementations (which will only grow over time). 141.154.19.152 (talk) 01:27, 5 June 2008 (UTC)

[edit] Disadvantages of Class D amplifiers

The article discusses their advantages but not their disadvantages. How come Class D amps aren't everywhere? — ciphergoth 08:43, 24 October 2007 (UTC)

[edit] Some absolute crap in the abstract (introduction)

(16:06, 22 October 2007):"Standard Class AB high-wattage power amplifiers are very heavy due to their bulky transformers and heat sinks. Class D amplifiers are lighter in weight and smaller than standard Class AB amplifiers, because they are more efficient. Class-D amplifiers use MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) rather than BJT transistors and they generate a triangular pulse waveform which is filtered at the output stage with a low pass filter to remove the high frequencies."

In these two sentences I have tree things to disagree with:

• The major distinguishing property of the switching is some lossless amplification. The elimination of weight of heat sink is a secondary, side, collateral, attribute of any non-dissipating device. (This is mainly an assent issue, but it is important to understand the principle rather than effects and applications, I believe)
• I'm sure, nobody uses the transformers to amplify the power.
• The transistors generate RECTANGULAR waveform rather triangular. The D-amplifier article authors even do not understand that the switches can generate nothing but the rectangular! The energy saving principle misunderstanding explains their misroute focusing on the wight. --Javalenok (talk) 17:01, 5 January 2008

I have corrected the edit today. --Javalenok (talk) 11:31, 6 March 2008 (UTC)

There's plenty of crap in the rest of it too. I tried to clean up a small part of it, but this article really needs a complete rewrite. Esobocinski 20:01, 27 March 2008 (UTC)

[edit] Make "Switching Amplifier" an overview and reference separate articles about classes

I really think that this article should be split such that "Switching Amplifier" would be an overview article with an explanation of switching and only brief descriptions of the different classes. Details belong in separate articles that get referenced hierarchically. Much of this article would end up as "Class D Amplifier" or somesuch, and "Class T Amplifier" would either become a section of that or would get hierarchically referenced below "Class D Amplifier". My preference is the latter. Esobocinski (talk) 19:59, 27 March 2008 (UTC)

Yes, that's the way to go - an overview article that makes it clear what they have in common that makes them a class or category, and some discussion of key differences (how they use feedback?); with separate articles (and categories) for specific topics and implementations. There are going to be more and more implementations of switching amplifiers, both because (1) the technology has now reached a level where full frequency range (and not just subwoofer) applications are used in the mass market and for audiophiles; and because (2) the low energy consumption / "green" aspect is becoming more valued. 141.154.19.152 (talk) 01:31, 5 June 2008 (UTC)

I'd conjecture that 99% of the content is the same between articles, differing only in minor details, and we should cover it all here. I think a list of other technologies would be helpful for deciding this, though. I'll start it. — Omegatron (talk) 03:09, 5 June 2008 (UTC)

Types of switching amplifiers that have articles:

• Class T amplifier