Regarding the parameter calculation of Snubber circuit, I have the following questions, please help to point out:
The first question: I have seen different descriptions of Rsnb values in different application manuals of TI. Would you like to confirm which is more reasonable? What is the value logic?
① In the application manual of TI -ZHCAA52, Chapter 3 Snubber buffer circuit mentioned Rsnb=√Lp/Cp (Lp is parasitic inductance, Cp is parasitic capacitance);
② It is mentioned in the Snubber parameter calculation in Section 1.3 of the TI application manual -ZHCA658 that R≥0.5x√Lp/Cp;
In addition, in Rohm's application manual "Snubber Circuit for Buck Converter IC", it is found that the Snubber parameter calculation is R=0.65x√Lp/Cp;
The second question: Regarding the value of Csnb, I have the following questions:
① Equation 11 in the TI application manual -ZHCA658 mentions that 1/2πf1Csnb=R/4, do not understand how this formula is obtained?
② It is mentioned in the application manual of TI -ZHCAA52 that Csnb=Cadd=3xCp, and I also saw in the application manual of Rohm that the value of Cp is 1-4 times. What is the logic here?
The above problems, have consulted a number of technical documents, most of them only write the result, did not mention the process logic, please also help to point under, thank you!
Related documents:
https://www.ti.com/cn/lit/an/zhca658/zhca658.pdf?ts=1710544725645
