Justification for the need for high voltage/power Class D amplifiers
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Posted by Matthew on November 16, 2004, 1:00 am
Please log in for more thread options I am doing a study in Class D power driver. Currently, reviewing the market feasibility. However, I have some questions. 1) What is the purpose of designing high voltage Class D power driver if it is not for portable devices? Isn't a Class AB enough to meet such requirements? 2) In what ways and why will Class D replace Class AB in the future? I understand that Class D has the following advantages: a)Compactness of overall design; b)Lower heat dissipation/high efficiency; c)Cost saving d)Energy saving Are there any other compelling reasons that Class D will replace Class AB? Appreciate any help. Thanks. | |||||||||||||
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Posted by Kevin Aylward on November 16, 2004, 9:54 am
Please log in for more thread options One application is high power pro audio gear. Once you get into the 1kW+ range it starts making better sense. >
> 2) In what ways and why will Class D replace Class AB in the future? It won't. >
> I understand that Class D has the following advantages: > > a)Compactness of overall design; There is little correlation between physical size and method. In fact, Class D usually requires more complicated circuitry to obtain decent performance. > b)Lower heat dissipation/high efficiency;
> c)Cost saving > d)Energy saving > > Are there any other compelling reasons that Class D will replace Class > AB? There aren't any compelling reasons for class D. Its just another method that had advantages in some situations, and disadvantages in others. Class D wont replace the other methods it is used in addition to the other methods. If your doing a study your supposed to identify the disadvantages as well as the advantages. You seem to be assuming the Class D is god's gift to amplifiers from the outset. It isn't. Kevin Aylward salesEXTRACT@anasoft.co.uk http://www.anasoft.co.uk SuperSpice, a very affordable Mixed-Mode Windows Simulator with Schematic Capture, Waveform Display, FFT's and Filter Design. | |||||||||||||
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Posted by john jardine on November 17, 2004, 4:28 am
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> Matthew wrote:
> > Hi,
>
Off hand it smacks of homework.
> If your doing a study your supposed to identify the disadvantages as > well as the advantages. You seem to be assuming the Class D is god's > gift to amplifiers from the outset. It isn't. > > Kevin Aylward > salesEXTRACT@anasoft.co.uk > http://www.anasoft.co.uk > SuperSpice, a very affordable Mixed-Mode > Windows Simulator with Schematic Capture, > Waveform Display, FFT's and Filter Design. > They're probably also indoctrinating 'em that digital will always replace analogue and that nothing worthy is designed below 10GHz and that microsoft is the best thing since sliced bread. regards john | |||||||||||||
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Posted by rayjking on November 17, 2004, 3:24 am
Please log in for more thread options Matthew,
The efficiency is better but a close second is crossover distortion. True Class D has no cross over distortion also the design is more simple over the temperature range because one fet is switched full on or off. Ray > Hi,
> > I am doing a study in Class D power driver. Currently, reviewing the > market feasibility. However, I have some questions. > > 1) What is the purpose of designing high voltage Class D power driver > if it is not for portable devices? Isn't a Class AB enough to meet > such requirements? > > 2) In what ways and why will Class D replace Class AB in the future? > > I understand that Class D has the following advantages: > > a)Compactness of overall design; > b)Lower heat dissipation/high efficiency; > c)Cost saving > d)Energy saving > > Are there any other compelling reasons that Class D will replace Class > AB? > > Appreciate any help. > > Thanks. | |||||||||||||
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Posted by rayjking on November 17, 2004, 12:52 pm
Please log in for more thread options Matthew,
Correction to my post. The other advantage to a switcher vs AB is the voltage rating of the switch and size of the out put transformer along with the power loss due to the bias current in the output transformer. a very good pwm can be made with two 555s and one IR2111. driving two totempole N fets. Ray > Matthew,
> > The efficiency is better but a close second is crossover distortion. True > Class D has no cross over distortion also the design is more simple over > the temperature range because one fet is switched full on or off. > > Ray > > > > > > Hi,
> > > > I am doing a study in Class D power driver. Currently, reviewing the > > market feasibility. However, I have some questions. > > > > 1) What is the purpose of designing high voltage Class D power driver > > if it is not for portable devices? Isn't a Class AB enough to meet > > such requirements? > > > > 2) In what ways and why will Class D replace Class AB in the future? > > > > I understand that Class D has the following advantages: > > > > a)Compactness of overall design; > > b)Lower heat dissipation/high efficiency; > > c)Cost saving > > d)Energy saving > > > > Are there any other compelling reasons that Class D will replace Class > > AB? > > > > Appreciate any help. > > > > Thanks. >
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> I am doing a study in Class D power driver. Currently, reviewing the
> market feasibility. However, I have some questions.
>
> 1) What is the purpose of designing high voltage Class D power driver
> if it is not for portable devices? Isn't a Class AB enough to meet
> such requirements?