Improved class BD

[lumanauw]

Class BD is known for 3 state, high-low-0. the well known patent is #6,097,249 from Rockford
I found this : http://www.google.com/patents?id=7nWHAAAAEBAJ&dq=robert+zeff+class+BD
It seems an improvement over Rockford's patent. Is it Robert Zeff of Zapco?
How can Fredos make classBD only with 2 output mosfets? http://www.diyaudio.com/forums/showthread.php?postid=904729#post904729

 

[lumanauw]

Old class BD patent#3585517

 

[fredos]

Good patent...It's easy to do with some logic gate...Cue: 2 out of phase triangle wave, on phase audio, 1 output coil with basic half bridge....

Fredos

 

[lumanauw]

Hi, Fredos,

Logic, is it like Robert Zeff application above (NOR gate), or like patent #6316964 or #6288605 or #5210449?

 

[fredos]

Bit different...Triangle are in phase and audio out of phase in these patents...I use in phase audio with out of phase triangle, with some cmos logic to achieve bd modulation...

 

[lumanauw]

If the definition of classBD is 3 state, this patent is interesting #7,218,173
I don't understand it. What is the function of Cramp and Rramp?

 

[kASD]

Bit different...Triangle are in phase and audio out of phase in these patents...I use in phase audio with out of phase triangle, with some cmos logic to achieve bd modulation...

In this way the audio output signal might suffer cross-over like distortion

 

[JZatopa]

Could someone tell me if this is valid enough to be considered a real new amplifier class or if it is just an extension of class D technology.

 

[kASD]

Its just another mode of operation in Class-D amplifiers.