Hello.
The attached circuit works fine with CC/CR loads,
but does not work with set loads.
If I change the integer value of part number C9 from 0.22UF to 1UF,
it works fine.
Can I change it?
Hello,
I see no issue with changing the soft start capacitor here.
A few questions just for understanding:
- With C9 being 0.22uF, what kind of loads were you seeing?
- Were you seeing excessive inrush for example?
- Finally, how in your observations does having C9 as 1uF change this exactly for the load?
Let me know,
Best,
Krishan
Hello, expert.
I don’t see any excessive input current at 0.22uF and 1UF.
The FET waveform at C9 0.22UF is a waveform that operates in hiccup mode and cannot start up. The waveform is normal at C9 1UF.
Could you please review the attached schematic?
Additional question.
If I set the resistance of R54 to 5.1 ohm or more, the DRV waveform
will oscillate as below.
Can I set it to 5.1 ohm or 0 ohm?
Hello, I see no apparent issues with the schematic that you have shared for the MP8017 or for the MP6951 (except for your additional question, which I will next address).
To answer your additional question regarding the DRV, the typical application shows that there should be no resistor connected between the DRV to the gate of your FET as shown:
Therefore, I would recommend 0 ohms. What was the motivation for adding a resistor here if I may ask?
Best,
Krishan