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EDITS:

Input voltage range: 24V to 48V. Changing the load current from 0.38A to 1.018A increases the mean output voltage from 12.779V to 13.26V. The supply should be producing 12.5V.

I'm using this IC - Link

enter image description here

The schematic has a saw tooth output voltage. The MIC2103 datasheet does not describe the internal compensation used - it is only shown as a box [Compensation].

I want to understand what is this compensation box and if possible can someone explain the Type II compensation or Type III compensation in just simple terms? I read it on the internet, but not getting enough clarity.

enter image description here

The mean output voltage rises with increased load. Why is this? Please explain

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    \$\begingroup\$ At 10 us time scale, that looks like burst mode with too little filtering. \$\endgroup\$
    – winny
    Commented Sep 1, 2022 at 6:45
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    \$\begingroup\$ You don't appear to have much output capacitance (data sheet implies over 500 uF). How much does the mean output voltage rise with load? What's the input voltage? What supplies the input voltage? What is the ripple on the input voltage? Establish that it's working correctly first. \$\endgroup\$
    – Andy aka
    Commented Sep 1, 2022 at 6:52
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    \$\begingroup\$ Look at the schematics \$\endgroup\$
    – Andy aka
    Commented Sep 1, 2022 at 7:30
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    \$\begingroup\$ At what load was the oscillogram taken? How did you end up with 4.7 uH and 44 uF on your output? \$\endgroup\$
    – winny
    Commented Sep 1, 2022 at 7:55
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    \$\begingroup\$ You’re not answering my questions. \$\endgroup\$
    – winny
    Commented Sep 3, 2022 at 18:35

1 Answer 1

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Talking about Type II and Type III compensation , Type II is proportional-Integral compensation and Type III is proportional-integral-derivative (PID) … that’s mean you add a compensation with a certain kind of transfert function and which will help you to adapt your circuit to have a good phase margin and Gain margin … type II transfert function can be seen as Kp + Ki/s , (Kp (proportional coefficient ) and Ki (integral coefficient ) real and s=jw) and Type III as (Kp + Ki/s)(1 + s/wz2) … with both Type the purpose is to create a phase boost by adding a RC network to enhance phase and gain Margin as said before … the idea is to create a pole at the origin follow by a zero to flatten the gain above wide frequency ( will boost phase )and follow by pole … in type II there is one zero and type III two zero (wz2 represent that second zero added) … I tried to explain it by a simple way but it’s no so straightforward

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