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  1. #21
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    Re: Half-Bridge 0-30V, 0-20A Feedback loop problem

    I've done more tests. I soldered 200nF between the comp and gnd plus plus the choke common mode choke and 4 capacitors 1000uF. The feedback loop was calculated as if the output capacity was 7000uF and the ESR was 3.57mohm.
    Now the whole thing works much better. The transformer at small loads is slightly playing but not terribly loud. Certainly much lower than before.

    He also adds graphs of output voltage, evaluate how it looks.

    Click image for larger version. 

Name:	DS1Z_QucikPrint1-2.5A.png 
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Size:	42.6 KB 
ID:	153787
    LOAD = 2.5A
    Click image for larger version. 

Name:	DS1Z_QucikPrint2-5A.png 
Views:	4 
Size:	48.0 KB 
ID:	153788
    LOAD = 5A
    Click image for larger version. 

Name:	DS1Z_QucikPrint3-7.5A.png 
Views:	2 
Size:	54.1 KB 
ID:	153789
    LOAD = 7.5A
    Click image for larger version. 

Name:	DS1Z_QucikPrint4-10A.png 
Views:	2 
Size:	54.3 KB 
ID:	153792
    LOAD = 10A
    Click image for larger version. 

Name:	DS1Z_QucikPrint5-15A.png 
Views:	2 
Size:	51.6 KB 
ID:	153790
    LOAD = 15A
    Click image for larger version. 

Name:	DS1Z_QucikPrint7-20A.png 
Views:	4 
Size:	41.0 KB 
ID:	153791
    LOAD = 20A



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  2. #22
    Advanced Member level 5
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    Re: Half-Bridge 0-30V, 0-20A Feedback loop problem

    you've got more damping at the higher loads - looking at the pictures



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  3. #23
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    Re: Half-Bridge 0-30V, 0-20A Feedback loop problem

    I do not know if I observed it well, but the higher the load, the feedback loop works at a lower frequency?

    Maybe if I moved a single pole (fp0) to a higher frequency it would be better?



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  4. #24
    Advanced Member level 5
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    Re: Half-Bridge 0-30V, 0-20A Feedback loop problem

    you have a loop issue at 2kHz, you need more phase lead at 1kHz ...



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