how they do that?

[Kuzmenko]

So, 3 years passed... Mr. Nelson and others, what you are thinking about that now?

 

[cascoder]

Class-D with soft-switching - anyone know of any?

Hello All,

I've been looking at the site for a wee-while, learning heaps, many thanks to Mr Nelson Pass for setting up this great resource. This is my 1st post... sorry if I break any protocols, if I have, then I offer my sincerest apologies, please just advise me what I may have done wrong, many thanks.

Just wondering about audio-amps based on transistors used as switches (Class-D); yes I agree that power electonics (inverters, motor drives, switch-mode power supplies, etc) are what seems to be the driver of this technology. Recent (say, 10years) developments in this market include circuit topologies where the switch (transistor) experiences far less switching power loss and so can switch at much higher frequencies (MHz for kW's of output power is possible, albeit for dc-output power supplies rather than audio frequency, as far as I know). This has varous names in the industry, some of which are "soft-switching", "zero-voltage switching", "zero-current switching", "Class-E", "loss-less switching", etc..

Is there any-body who has noticed any of these technologies being implemented in audio amplifiers (other than in the DC power supply, though). Any info would be greatly appreciated.

Cheers,

 

[SpittinLLama]

Class E and F are only used in communications. They cannot really be used in audio amplifiers as well as Class C. As far as I know there are only Class A, Class AB, Class D, Class G, Class H and a very unknown Class S which was originally what we call Class D today that can be used for audio amps. Any other calls like Class I, Class T etc is really one of these classes. The BASH amplifiers made by ST and Indigo are just a Class G/H hybrid. IIRC, Class I is just Class D (called Class BD) and Clas T (Tripath's chips) is just a Class D. They only call it Class T because of their name which is devrived from the founder's last name.

-SL

 

[Nelson Pass]

Re: Class-D with soft-switching - anyone know of any?

I've been looking at the site for a wee-while, learning heaps, many thanks to Mr Nelson Pass for setting up this great resource.

I can't take any of the credit. It was sitting here running nicely
long before I showed up.

 

[Viennatom_new]

Does anybody know when patent # US005657219A will expire? The Date of patent = Aug. 12, 1997. Is the Opposed current converter patented in all countries and is the expiration date everywhere the same? I am inclined to build and sell amps of this topology as soon as it is legal.