DIY Good Class D amplifier

[ravslanka]

Have you tried shorting input to ground first?

In my prototype I don't have any noise (It's very small)
Try to change output filter,and try PetruV suggestion.

hi acca and petruv,


please checkout

first video with shorted input to ground

DSCN0110 - YouTube

this one without shorting

DSCN0113 - YouTube

changing output filter no difference


regards

ravs

 

[Acca]

Hello,good work.
Do you mean 50hz noise?

 

[Acca]

What power supply you use?

 

[Acca]

Measure current from power supply of fets with gnd short and post here
Maybe level shifter make problem,and both transistors conduct at same time,shorting psu and making ripple.

 

[Acca]

Oh,i get it,i will try smps

Do you tried?

 

[ravslanka]

Hello,good work.
Do you mean 50hz noise?

What power supply you use?

Measure current from power supply of fets with gnd short and post here
Maybe level shifter make problem,and both transistors conduct at same time,shorting psu and making ripple.

hi acca,

no not 50hz nosw.using 50hz transnsformer 24-0-24 ac as a source ets are irf540n.one side fet get little warn and other remain cool.

ill measure the voltages and post later .

thanks

ravs

 

[Acca]

Sory but I don't understand
What noise you mean 50hz or switching?
Try to filter your psu.
Both fets must have same temp.

 

[ravslanka]

Sory but I don't understand
What noise you mean 50hz or switching?
Try to filter your psu.
Both fets must have same temp.

acca please check those video links in my early post

 

[Acca]

I checked,and I hear 50Hz noise and some crackling

 

[ravslanka]

yes thats the noise .dont know what they are 50hz or switchinng noise.
using mains transformer not smps 4700uf per rail.sometimes only one side mosfet get warm

 

[Acca]

Try to source IR2184,I don't know now do ir2110 have internal dead time.In few days I'll try with optocopuler drive,and post here if have success.

 

[ravslanka]

Try to source IR2184,I don't know now do ir2110 have internal dead time.In few days I'll try with optocopuler drive,and post here if have success.

2184 very expensive uver here.

regards

ravs

 

[Acca]

Ok.Try to decrease freq. first.
If not help,try to merge inverting input and output of SG internal opamp with input to gnd.
Crackling and 50hz isn't switching noise.

 

[PetruV]

could be emi,i knew a lot of people with this problem or defective or fake chips,but i think it is a bad solder joint by the crackling,very common problem

 

[Acca]

Fake chips...
My friend have one IR2153 for smps,and set freq to 50khz with R and C according to datasheet,and when measure freq. he have 180kHz
Yes,maybe have bad solder joint.Try to press PCB and see do it any change.

 

[PetruV]

When will the optocoupler version will be released?

 

[Acca]

In few days,tomorrow I'll try with it.

 

[Acca]

I tried it,and result is bad.DIY opto can't be used for this
Maybe high speed comercial can be used,but I go to finish class D SMPS. (direct class D from modified atx).

 

[PetruV]

what happened?

 

[Acca]

Very slow rising and falling edges.