New classD amp: Gemincore of CL3

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Jump to Latest
sx881663

sx881663

Member
Joined 2003
Posted circuit

Kanwar,
Clever but not a source follower at all as the output stage switches at full +/- 40v swing. What I see as the real problem is that you will have the power supplies swinging at the full rail voltages, bound to create a monumental amount of EMI.
This is one of those that will run very well on LTspice but is totally impractical in reality.
Roger
 
kASD

kASD

Member
Joined 2004
Re: Posted circuit

sx881663 said:
Kanwar,
Clever but not a source follower at all as the output stage switches at full +/- 40v swing. What I see as the real problem is that you will have the power supplies swinging at the full rail voltages, bound to create a monumental amount of EMI.
This is one of those that will run very well on LTspice but is totally impractical in reality.
Roger
Click to expand...

Incorrect, only reference node "earth" is shifted from power-supply to sources of switches....indeed its a grounded source follower
BTW I dont use LTspice.....nor its impractical in reality ...because it has been made in reality, that amp;)

The EMI is same whether you use floating supply or conventional design...

K a n w a r
 
Eva

Eva

Member
Joined 2003
The amount of EMI radiated will be proportional to the area of the current loops involved and to the surface of the conductors whose voltage swings quickly with respect to earth. In other words, switching the supplies will always produce more EMI, even when proper common mode filtering is employed.

A far better idea is to make the driver side floating.
 
sx881663

sx881663

Member
Joined 2003
Re: Re: Posted circuit

Workhorse said:


Incorrect, only reference node "earth" is shifted from power-supply to sources of switches....indeed its a grounded source follower
BTW I dont use LTspice.....nor its impractical in reality ...because it has been made in reality, that amp;)

The EMI is same whether you use floating supply or conventional design...

K a n w a r
Click to expand...

I didn't say it wouldn't work, it will. If the ground is being shifted what is the input signal referenced to? If the ground is not really ground what is? There has to be a ground reference to relate the input to as it is shown as single ended. For that matter all the voltages called out must be in reference to something unless they are battery sources. What keeps the +/- 40 volt supplies from shifting with the switching? If the source is grounded and the drain is an active node how can this be a source follower? You have really confused me, I require education.
Roger
 
K

koolkid731

Member
Joined 2005
Workhorse said:
Hi Folks,

I am currently working on this Grounded Source Follower topology for lower power versions upto 200W in Class-D complementary FETs...Easy drivability and low cost.....Whereas my high power versions use N-channel Mosfets only....

Have a look....
regards,
K a n w a r
Click to expand...

How and when did you come up with the idea?

I built a more "advanced" version 3 years ago. I have the date etched on the PCB to prove.

I don't think it's patentable nor patented, at least if USPTO examiners were competent. It's like saying the push-pull configuration is patentable over the single-ended configuration although the former is doubling of the latter.
 
K

koolkid731

Member
Joined 2005
@ Workhorse: Like I said, IMO it's not patented nor patentable, because I know too many prior art source follower circuits, Jacman's is but one example but dated 2/2004. He got TWO source followers in a same schematic. 'nuf said. I already cited the 70's totem poles.

On the subject of patents, many are allowed only due to limitation of knowledge of patent examiners. Most patents are nothing more than a piece of paper on the wall.

I certainly don't worry a bit about any patent. They do however provide inspiration for better inventions.
 
sx881663

sx881663

Member
Joined 2003
More elegant?

Jaka,
Much less physical mass getting switched at HF, yes a more elegant solution. The +/- 12V power could be a very small SMPS and shielded. I like the way the drive is bootstrapped and limited so a shorted load wouldn’t destroy the outputs due to over voltage. An output inductor would limit the amount of switching current, hopefully. I would imagine the inductor would get quite toasty though.
I don't understand the use of the internal inductor and what it does best. It seems as though the driver would be working into essentially an open circuit at switching frequencies. Of course the 12 volt supply common would need to be referenced to the output, this is not shown.
Roger
 
C

classd4sure

Disabled Account
Joined 2004
diyaudio.com
koolkid731 said:
@ Workhorse: Like I said, IMO it's not patented nor patentable, because I know too many prior art source follower circuits, Jacman's is but one example but dated 2/2004. He got TWO source followers in a same schematic. 'nuf said. I already cited the 70's totem poles.

On the subject of patents, many are allowed only due to limitation of knowledge of patent examiners. Most patents are nothing more than a piece of paper on the wall.

I certainly don't worry a bit about any patent. They do however provide inspiration for better inventions.
Click to expand...


Ah HAH! You see? What they've done is find a more elegant solution to the known source follower such as Jaka's obese dual follower arrangement.. :clown:

"I certainly don't worry a bit about any patent."
Bold statement considering..

It'd be interesting to know just how many patents would be violated these days given the most basic class d implementation.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Top Bottom