IC Controlers for Class D Power stage

I am building a Class D amplifier and I am looking for a controler IC.

I am after awesome THD+N lower than 0.1%

The control chip must me able to handel a 500W RMS plus power stage output.

I have seen the MUETA and they look very good but I have not heard a response from the company.

I would also like to find out what other chips are avaliable so that I can review all my options before committing.
frozenpod1 said:
I am looking for a controler which will provide which me with dead time 500KHz 3 level PWM and has been used to produce at least 100W at less than 0.1% THD+N

Most people build their own controller. 0.1% distortion is quite high by nearly everyone's standard (bar the proponents of open loop digitally controlled amps, they will put up with anything as long as they can stick the digital label onto it).
A 3-level controller is simply two 2-level modulators sharing one clock and integrating control loop. Getting good distortion results from 3-level schemes is difficult. For one it won't work well using a differential LC filter because you loose the soft-switching advantage resulting in large amounts of distortion at low signal levels (unless you actually have the MOSFET timing overlap somewhat). You need two separate LC filters instead. Then, crosstalk between the two power stages and comparators is another source of problems, again around zero crossings.

In other words, may I suggest that you have a go at 2-level modulation first?


2004-12-25 12:24 pm
frozenpod1 said:
In power electronic inverters 3 level modulation is almost always used.

The increase in performance at 50Hz is very large when going from 2 to 3 level.

That is why I was going to use 3 but I may have to reconsider

We also use 3 level modulation scheme in our subwoofer amp, in which switching frequency is in phase but audio signal is out of phase, in this configuration the size of output filter could be made small as compared to 2-level. And the damping factor also improves alot . it also minimises the distortion effects and eliminates bus pumping as well.
Are you not concerend with the audio signal being out of phase as in the canceling effect with other speakers which are in phase.

Also there is a difference in the way we hear sounds wether the first peak is positive or negative air pressure, there have been test which prove there is a difference that is why it is very important to insure that the amplifier is in phase or out of phase by 360 deg.