New Module by Lars Clausen

[IVX]

Originally posted by Lars Clausen
IVX: Thank You for bringing this nice little chip into scope. But according to Philips's own datasheet:

http://www.semiconductors.philips.co...7/75013749.pdf

The THD is not 3 times lower than 0.001% (0.0003%) but rather 0.05%. This is 50 times MORE distortion.... ??

THD here shown in a reference design from Cirrus Logic:

Hint: according to ST own datasheet, L6387 THD isn't specified at all.

[Lars Clausen]

IVX: very true, neither is it for L6385D, which is the one i am using

BTW how do you make these quote fields? I always make them manually, but i think you are using a little bit smarter way???

[phase_accurate]

Hi Ivan

I am not interested in the 1 W performance of a 20 Watt amp but the 1 Watt performance of amps of > 100 Watt of output power.

Regards

Charles

[Lars Clausen]

IVX: With regards to your question about Bruno Putzeys' patents in relation to the NewClassD RC network, i have read his patent claims closely for this particular part.

Here are the claims that come into scope:

From the Patent...

Claims:

1. Power amplifier for amplifying an electric signal in an operational frequency range comprising switching means for generating a block wave signal by alternately switching the block wave signal to a first supply voltage or a second supply voltage, filter means for generating a power output signal by low pass filtering the block wave signal, input means for receiving the electric signal and driving the switching means, and a control circuit coupled to the output power signal and the input means for controlling the power amplifier, characterized in that the control circuit is connected between the power output signal and a linear input of the input means for controlling both the gain in the operational frequency range and also said alternately switching of the switching means, said linear input being substantially free of hysteresis.

2. Power amplifier as claimed in claim 1, wherein the control circuit only has a voltage feedback from the power output signal.

3. Power amplifier as claimed in claim 2, wherein the control circuit comprises a first element, in particular a resistor, for controlling said gain and a second element, in particular a capacitance in series with a resistor, for controlling said alternately switching.

Now as you can see, i have a capacitance in parallel with a resistor, coupled in series with another resistor. This is not the same as Bruno's patents claim. However i do admit that the resulting circuit function is somewhat comparable.

So just to be sure, i have sent a mail to Jan-Peter asking if they see it as a violation, in which case it would of course have to be resolved properly.

[fredos]

Thanks for your reply Lars Clausen!

I agree that low volume production should be sold at hight price...The difference with me is that prototypes is design to be stable in mass production. Performance was excelent, but not tuned each one as your. That why I can sold module as at such low price. I already sold these module for fews commercial company (some pro too, but cannot give any name here...) that use it in Surround sound system or in multichannel pro audio amp. I only sold module, they do all the rest.

Nice work, seem interesting way the micro-controler!

Fredos

www.d-amp.com

[phase_accurate]

A cap in parallel with a resistor isn't that new at all. It is a circuit detail used since decades in PID controllers.
I don't think that this detail violates the UcD patent.

Regards

Charles

[Snickers-is]

I think both this kind of circuit, and something very similar to the circuit of Putzeys' patent was implemented in the circuits developed by a Norwegian engineer in 1970. It was a class D with 1,5MHz switching frequency, running at 30W and a stunning 99% efficiency (with bipolar transistors!). I do not remember for sure what company he worked for.

Clausen, is it so that the delay time causes the rise in distorsion when runnng at higher switching frequencies?

(If you want to post a quote you have to check the checkbox at the lower right corner of the post before you hit the answer-button.)

[igy137]

Lars,

Do you have an estimate when the first modules will be available?

igy137

[Lars Clausen]

Charles: Thanks for the support! I did find a reference design with exacly the same feedback topology as used in UcD, dating before Hypex' patent date. It can be seen here:

http://focus.ti.com/lit/an/slua286/slua286.pdf

It's a PWM regulator, but essentially very similar to the circuit described in the UcD patent.

But of course i have no intent of offending my friends in Hypex, so it will be my pleasure to redesign the global loop, as to be sure it does not collide with the UcD patent.

Which btw can be seen here

[IVX]

Lars, Quote script it's a really really strong voodoo, turn on your intuition and you'll see Quote:_check_box in the right bottom corner. ;-)
Charles, i mean 20W performance of the 80W amp versus 1W performance of the 400W amp. I agree about UcD patent, but it make possibility for anyone to use this stuff if additional res added, even 1Ohm or less. BTW, boringly without Bruno here. :-(